title: NFPA 704

text: The four divisions are typically color-coded with red on top indicating flammability, blue on the left indicating level of health hazard, yellow on the right for chemical reactivity, and white containing codes for special hazards. Each of health, flammability and reactivity is rated on a scale from 0 (no hazard) to 4 (severe hazard). The latest version of NFPA 704 sections 5, 6, 7 and 8 for the specifications of each classification are listed below. The numeric values in the first column are designated in the standard by "Degree of Hazard" using Arabic numerals (0, 1, 2, 3, 4), not to be confused with other classification systems, such as that in the NFPA 30 Flammable and Combustible Liquids Code, where flammable and combustible liquid categories are designated by "Class", using Roman numerals (I, II, III).


title: NFPA 704

text: The development of NFPA 704 is credited to the Charlotte Fire Department after a fire at the Charlotte Chemical Company in 1959 led to severe injuries to many of the firefighters. Upon arrival, the fire crew found a fire burning inside a vat that firefighters assumed to be burning kerosene. The crew tried to suppress the fire, which resulted in the vat exploding due to metallic sodium being stored in the kerosene. Thirteen firefighters were injured, including several of whom had critical injuries and one who lost both ears and most of his face from the incident.


title: NFPA 704

text: At the time, such vats were not labelled with the materials they contained, so firefighters didn't have the necessary information to recognize that hazardous materials were present, which required a specific response. In this case, sodium was able to react with water to release hydrogen gas and large amounts of heat, which has the potential to explode.


title: NFPA 704

text: The Charlotte Fire Department developed training to respond to fires involving hazardous materials, ensured that protective clothing was available to those responding, and expanded the fire prevention inspection program. Fire Marshal J. F. Morris developed the diamond shaped placard as a marking system to indicate when a building contained hazardous materials, with their levels of flammability, reactivity and health effects.


title: Kernel (operating system)

text: The kernel is a computer program at the core of a computer's operating system and generally has complete control over everything in the system. It is the portion of the operating system code that is always resident in memory and facilitates interactions between hardware and software components. A full kernel controls all hardware resources (e.g. I/O, memory, cryptography) via device drivers, arbitrates conflicts between processes concerning such resources, and optimizes the utilization of common resources e.g. CPU & cache usage, file systems, and network sockets. On most systems, the kernel is one of the first programs loaded on startup (after the bootloader). It handles the rest of startup as well as memory, peripherals, and input/output (I/O) requests from software, translating them into data-processing instructions for the central processing unit.


title: Kernel (operating system)

text: The critical code of the kernel is usually loaded into a separate area of memory, which is protected from access by application software or other less critical parts of the operating system. The kernel performs its tasks, such as running processes, managing hardware devices such as the hard disk, and handling interrupts, in this protected kernel space. In contrast, application programs such as browsers, word processors, or audio or video players use a separate area of memory, user space. This separation prevents user data and kernel data from interfering with each other and causing instability and slowness, as well as preventing malfunctioning applications from affecting other applications or crashing the entire operating system. Even in systems where the kernel is included in application address spaces, memory protection is used to prevent unauthorized applications from modifying the kernel.


title: Kernel (operating system)

text: The kernel's interface is a low-level abstraction layer. When a process requests a service from the kernel, it must invoke a system call, usually through a wrapper function.


title: Kernel (operating system)

text: There are different kernel architecture designs. Monolithic kernels run entirely in a single address space with the CPU executing in supervisor mode, mainly for speed. Microkernels run most but not all of their services in user space, like user processes do, mainly for resilience and modularity. MINIX 3 is a notable example of microkernel design. Instead, the Linux kernel is monolithic, although it is also modular, for it can insert and remove loadable kernel modules at runtime.


title: Kernel (operating system)

text: This central component of a computer system is responsible for executing programs. The kernel takes responsibility for deciding at any time which of the many running programs should be allocated to the processor or processors.


title: Kernel (operating system)

text: Random-access memory (RAM) is used to store both program instructions and data. Typically, both need to be present in memory in order for a program to execute. Often multiple programs will want access to memory, frequently demanding more memory than the computer has available. The kernel is responsible for deciding which memory each process can use, and determining what to do when not enough memory is available.


title: Kernel (operating system)

text: I/O devices include such peripherals as keyboards, mice, disk drives, printers, USB devices, network adapters, and display devices. The kernel allocates requests from applications to perform I/O to an appropriate device and provides convenient methods for using the device (typically abstracted to the point where the application does not need to know implementation details of the device).


title: Kernel (operating system)

text: Key aspects necessary in resource management are defining the execution domain (address space) and the protection mechanism used to mediate access to the resources within a domain. Kernels also provide methods for synchronization and inter-process communication (IPC). These implementations may be located within the kernel itself or the kernel can also rely on other processes it is running. Although the kernel must provide IPC in order to provide access to the facilities provided by each other, kernels must also provide running programs with a method to make requests to access these facilities. The kernel is also responsible for context switching between processes or threads.


title: Kernel (operating system)

text: The kernel has full access to the system's memory and must allow processes to safely access this memory as they require it. Often the first step in doing this is virtual addressing, usually achieved by paging and/or segmentation. Virtual addressing allows the kernel to make a given physical address appear to be another address, the virtual address. Virtual address spaces may be different for different processes; the memory that one process accesses at a particular (virtual) address may be different memory from what another process accesses at the same address. This allows every program to behave as if it is the only one (apart from the kernel) running and thus prevents applications from crashing each other.


title: Kernel (operating system)

text: On many systems, a program's virtual address may refer to data which is not currently in memory. The layer of indirection provided by virtual addressing allows the operating system to use other data stores, like a hard drive, to store what would otherwise have to remain in main memory (RAM). As a result, operating systems can allow programs to use more memory than the system has physically available. When a program needs data which is not currently in RAM, the CPU signals to the kernel that this has happened, and the kernel responds by writing the contents of an inactive memory block to disk (if necessary) and replacing it with the data requested by the program. The program can then be resumed from the point where it was stopped. This scheme is generally known as demand paging.


title: Kernel (operating system)

text: Virtual addressing also allows creation of virtual partitions of memory in two disjointed areas, one being reserved for the kernel (kernel space) and the other for the applications (user space). The applications are not permitted by the processor to address kernel memory, thus preventing an application from damaging the running kernel. This fundamental partition of memory space has contributed much to the current designs of actual general-purpose kernels and is almost universal in such systems, although some research kernels (e.g., Singularity) take other approaches.


title: Kernel (operating system)

text: To perform useful functions, processes need access to the peripherals connected to the computer, which are controlled by the kernel through device drivers. A device driver is a computer program encapsulating, monitoring and controlling a hardware device (via its Hardware/Software Interface (HSI)) on behalf of the OS. It provides the operating system with an API, procedures and information about how to control and communicate with a certain piece of hardware. Device drivers are an important and vital dependency for all OS and their applications. The design goal of a driver is abstraction; the function of the driver is to translate the OS-mandated abstract function calls (programming calls) into device-specific calls. In theory, a device should work correctly with a suitable driver. Device drivers are used for e.g. video cards, sound cards, printers, scanners, modems, and Network cards.


title: Kernel (operating system)

text: For example, to show the user something on the screen, an application would make a request to the kernel, which would forward the request to its display driver, which is then responsible for actually plotting the character/pixel.


title: Kernel (operating system)

text: A kernel must maintain a list of available devices. This list may be known in advance (e.g., on an embedded system where the kernel will be rewritten if the available hardware changes), configured by the user (typical on older PCs and on systems that are not designed for personal use) or detected by the operating system at run time (normally called plug and play). In plug-and-play systems, a device manager first performs a scan on different peripheral buses, such as Peripheral Component Interconnect (PCI) or Universal Serial Bus (USB), to detect installed devices, then searches for the appropriate drivers.


title: Kernel (operating system)

text: As device management is a very OS-specific topic, these drivers are handled differently by each kind of kernel design, but in every case, the kernel has to provide the I/O to allow drivers to physically access their devices through some port or memory location. Important decisions have to be made when designing the device management system, as in some designs accesses may involve context switches, making the operation very CPU-intensive and easily causing a significant performance overhead.


title: Kernel (operating system)

text: In computing, a system call is how a process requests a service from an operating system's kernel that it does not normally have permission to run. System calls provide the interface between a process and the operating system. Most operations interacting with the system require permissions not available to a user-level process, e.g., I/O performed with a device present on the system, or any form of communication with other processes requires the use of system calls.


title: Kernel (operating system)

text: A system call is a mechanism that is used by the application program to request a service from the operating system. They use a machine-code instruction that causes the processor to change mode. An example would be from supervisor mode to protected mode. This is where the operating system performs actions like accessing hardware devices or the memory management unit. Generally the operating system provides a library that sits between the operating system and normal user programs. Usually it is a C library such as Glibc or Windows API. The library handles the low-level details of passing information to the kernel and switching to supervisor mode. System calls include close, open, read, wait and write.


title: Kernel (operating system)

text: To actually perform useful work, a process must be able to access the services provided by the kernel. This is implemented differently by each kernel, but most provide a C library or an API, which in turn invokes the related kernel functions.


title: Kernel (operating system)

text: The method of invoking the kernel function varies from kernel to kernel. If memory isolation is in use, it is impossible for a user process to call the kernel directly, because that would be a violation of the processor's access control rules. A few possibilities are:


title: Kernel (operating system)

text: An important consideration in the design of a kernel is the support it provides for protection from faults (fault tolerance) and from malicious behaviours (security). These two aspects are usually not clearly distinguished, and the adoption of this distinction in the kernel design leads to the rejection of a hierarchical structure for protection.


title: Kernel (operating system)

text: The mechanisms or policies provided by the kernel can be classified according to several criteria, including: static (enforced at compile time) or dynamic (enforced at run time); pre-emptive or post-detection; according to the protection principles they satisfy (e.g., Denning); whether they are hardware supported or language based; whether they are more an open mechanism or a binding policy; and many more.


title: Kernel (operating system)

text: Many kernels provide implementation of "capabilities", i.e., objects that are provided to user code which allow limited access to an underlying object managed by the kernel. A common example is file handling: a file is a representation of information stored on a permanent storage device. The kernel may be able to perform many different operations, including read, write, delete or execute, but a user-level application may only be permitted to perform some of these operations (e.g., it may only be allowed to read the file). A common implementation of this is for the kernel to provide an object to the application (typically so called a "file handle") which the application may then invoke operations on, the validity of which the kernel checks at the time the operation is requested. Such a system may be extended to cover all objects that the kernel manages, and indeed to objects provided by other user applications.


title: Kernel (operating system)

text: An efficient and simple way to provide hardware support of capabilities is to delegate to the memory management unit (MMU) the responsibility of checking access-rights for every memory access, a mechanism called capability-based addressing. Most commercial computer architectures lack such MMU support for capabilities.


title: Kernel (operating system)

text: An alternative approach is to simulate capabilities using commonly supported hierarchical domains. In this approach, each protected object must reside in an address space that the application does not have access to; the kernel also maintains a list of capabilities in such memory. When an application needs to access an object protected by a capability, it performs a system call and the kernel then checks whether the application's capability grants it permission to perform the requested action, and if it is permitted performs the access for it (either directly, or by delegating the request to another user-level process). The performance cost of address space switching limits the practicality of this approach in systems with complex interactions between objects, but it is used in current operating systems for objects that are not accessed frequently or which are not expected to perform quickly.


title: Kernel (operating system)

text: If the firmware does not support protection mechanisms, it is possible to simulate protection at a higher level, for example by simulating capabilities by manipulating page tables, but there are performance implications. Lack of hardware support may not be an issue, however, for systems that choose to use language-based protection.


title: Kernel (operating system)

text: An important kernel design decision is the choice of the abstraction levels where the security mechanisms and policies should be implemented. Kernel security mechanisms play a critical role in supporting security at higher levels.


title: Kernel (operating system)

text: One approach is to use firmware and kernel support for fault tolerance (see above), and build the security policy for malicious behavior on top of that (adding features such as cryptography mechanisms where necessary), delegating some responsibility to the compiler. Approaches that delegate enforcement of security policy to the compiler and/or the application level are often called "language-based security".


title: Kernel (operating system)

text: The lack of many critical security mechanisms in current mainstream operating systems impedes the implementation of adequate security policies at the application abstraction level. In fact, a common misconception in computer security is that any security policy can be implemented in an application regardless of kernel support.


title: Kernel (operating system)

text: According to Mars Research Group developers, a lack of isolation is one of the main factors undermining kernel security. They propose their driver isolation framework for protection, primarily in the Linux kernel.


title: Kernel (operating system)

text: Typical computer systems today use hardware-enforced rules about what programs are allowed to access what data. The processor monitors the execution and stops a program that violates a rule, such as a user process that tries to write to kernel memory. In systems that lack support for capabilities, processes are isolated from each other by using separate address spaces. Calls from user processes into the kernel are regulated by requiring them to use one of the above-described system call methods.


title: Kernel (operating system)

text: An alternative approach is to use language-based protection. In a language-based protection system, the kernel will only allow code to execute that has been produced by a trusted language compiler. The language may then be designed such that it is impossible for the programmer to instruct it to do something that will violate a security requirement.


title: Kernel (operating system)

text: Edsger Dijkstra proved that from a logical point of view, atomic lock and unlock operations operating on binary semaphores are sufficient primitives to express any functionality of process cooperation. However this approach is generally held to be lacking in terms of safety and efficiency, whereas a message passing approach is more flexible. A number of other approaches (either lower- or higher-level) are available as well, with many modern kernels providing support for systems such as shared memory and remote procedure calls.


title: Kernel (operating system)

text: The idea of a kernel where I/O devices are handled uniformly with other processes, as parallel co-operating processes, was first proposed and implemented by Brinch Hansen (although similar ideas were suggested in 1967). In Hansen's description of this, the "common" processes are called "internal processes", while the I/O devices are called "external processes".


title: Kernel (operating system)

text: Similar to physical memory, allowing applications direct access to controller ports and registers can cause the controller to malfunction, or system to crash. With this, depending on the complexity of the device, some devices can get surprisingly complex to program, and use several different controllers. Because of this, providing a more abstract interface to manage the device is important. This interface is normally done by a device driver or hardware abstraction layer. Frequently, applications will require access to these devices. The kernel must maintain the list of these devices by querying the system for them in some way. This can be done through the BIOS, or through one of the various system buses (such as PCI/PCIE, or USB). Using an example of a video driver, when an application requests an operation on a device, such as displaying a character, the kernel needs to send this request to the current active video driver. The video driver, in turn, needs to carry out this request. This is an example of inter-process communication (IPC).


title: Kernel (operating system)

text: Naturally, the above listed tasks and features can be provided in many ways that differ from each other in design and implementation.


title: Kernel (operating system)

text: The principle of "separation of mechanism and policy" is the substantial difference between the philosophy of micro and monolithic kernels. Here a "mechanism" is the support that allows the implementation of many different policies, while a policy is a particular "mode of operation". Example:


title: Kernel (operating system)

text: Because the mechanism and policy are separated, the policy can be easily changed to e.g. require the use of a security token.


title: Kernel (operating system)

text: In minimal microkernel just some very basic policies are included, and its mechanisms allows what is running on top of the kernel (the remaining part of the operating system and the other applications) to decide which policies to adopt (as memory management, high level process scheduling, file system management, etc.). A monolithic kernel instead tends to include many policies, therefore restricting the rest of the system to rely on them.


title: Kernel (operating system)

text: Per Brinch Hansen presented arguments in favour of separation of mechanism and policy. The failure to properly fulfill this separation is one of the major causes of the lack of substantial innovation in existing operating systems, a problem common in computer architecture. The monolithic design is induced by the "kernel mode"/"user mode" architectural approach to protection (technically called hierarchical protection domains), which is common in conventional commercial systems; in fact, every module needing protection is therefore preferably included into the kernel. This link between monolithic design and "privileged mode" can be reconducted to the key issue of mechanism-policy separation; in fact the "privileged mode" architectural approach melds together the protection mechanism with the security policies, while the major alternative architectural approach, capability-based addressing, clearly distinguishes between the two, leading naturally to a microkernel design (see Separation of protection and security).


title: Kernel (operating system)

text: While monolithic kernels execute all of their code in the same address space (kernel space), microkernels try to run most of their services in user space, aiming to improve maintainability and modularity of the codebase. Most kernels do not fit exactly into one of these categories, but are rather found in between these two designs. These are called hybrid kernels. More exotic designs such as nanokernels and exokernels are available, but are seldom used for production systems. The Xen hypervisor, for example, is an exokernel.


title: Kernel (operating system)

text: In a monolithic kernel, all OS services run along with the main kernel thread, thus also residing in the same memory area. This approach provides rich and powerful hardware access. Some developers, such as UNIX developer Ken Thompson, maintain that it is "easier to implement a monolithic kernel" than microkernels. The main disadvantages of monolithic kernels are the dependencies between system components a bug in a device driver might crash the entire system and the fact that large kernels can become very difficult to maintain.


title: Kernel (operating system)

text: Monolithic kernels, which have traditionally been used by Unix-like operating systems, contain all the operating system core functions and the device drivers. This is the traditional design of UNIX systems. A monolithic kernel is one single program that contains all of the code necessary to perform every kernel-related task. Every part which is to be accessed by most programs which cannot be put in a library is in the kernel space: Device drivers, scheduler, memory handling, file systems, and network stacks. Many system calls are provided to applications, to allow them to access all those services. A monolithic kernel, while initially loaded with subsystems that may not be needed, can be tuned to a point where it is as fast as or faster than the one that was specifically designed for the hardware, although more relevant in a general sense. Modern monolithic kernels, such as those of Linux (one of the kernels of the GNU operating system) and FreeBSD kernel, both of which fall into the category of Unix-like operating systems, feature the ability to load modules at runtime, thereby allowing easy extension of the kernel's capabilities as required, while helping to minimize the amount of code running in kernel space. In the monolithic kernel, some advantages hinge on these points:


title: Kernel (operating system)

text: Most work in the monolithic kernel is done via system calls. These are interfaces, usually kept in a tabular structure, that access some subsystem within the kernel such as disk operations. Essentially calls are made within programs and a checked copy of the request is passed through the system call. Hence, not far to travel at all. The monolithic Linux kernel can be made extremely small not only because of its ability to dynamically load modules but also because of its ease of customization. In fact, there are some versions that are small enough to fit together with a large number of utilities and other programs on a


title: Kernel (operating system)

text: single floppy disk and still provide a fully functional operating system (one of the most popular of which is muLinux). This ability to miniaturize its kernel has also led to a rapid growth in the use of Linux in embedded systems.


title: Kernel (operating system)

text: These types of kernels consist of the core functions of the operating system and the device drivers with the ability to load modules at runtime. They provide rich and powerful abstractions of the underlying hardware. They provide a small set of simple hardware abstractions and use applications called servers to provide more functionality. This particular approach defines a high-level virtual interface over the hardware, with a set of system calls to implement operating system services such as process management, concurrency and memory management in several modules that run in supervisor mode.


title: Kernel (operating system)

text: Microkernel (also abbreviated μK or uK) is the term describing an approach to operating system design by which the functionality of the system is moved out of the traditional "kernel", into a set of "servers" that communicate through a "minimal" kernel, leaving as little as possible in "system space" and as much as possible in "user space". A microkernel that is designed for a specific platform or device is only ever going to have what it needs to operate. The microkernel approach consists of defining a simple abstraction over the hardware, with a set of primitives or system calls to implement minimal OS services such as memory management, multitasking, and inter-process communication. Other services, including those normally provided by the kernel, such as networking, are implemented in user-space programs, referred to as "servers". Microkernels are easier to maintain than monolithic kernels, but the large number of system calls and context switches might slow down the system because they typically generate more overhead than plain function calls.


title: Kernel (operating system)

text: Only parts which really require being in a privileged mode are in kernel space: IPC (Inter-Process Communication), basic scheduler, or scheduling primitives, basic memory handling, basic I/O primitives. Many critical parts are now running in user space: The complete scheduler, memory handling, file systems, and network stacks. Micro kernels were invented as a reaction to traditional "monolithic" kernel design, whereby all system functionality was put in a one static program running in a special "system" mode of the processor. In the microkernel, only the most fundamental of tasks are performed such as being able to access some (not necessarily all) of the hardware, manage memory and coordinate message passing between the processes. Some systems that use micro kernels are QNX and the HURD. In the case of QNX and Hurd user sessions can be entire snapshots of the system itself or views as it is referred to. The very essence of the microkernel architecture illustrates some of its advantages:


title: Kernel (operating system)

text: Most microkernels use a message passing system to handle requests from one server to another. The message passing system generally operates on a port basis with the microkernel. As an example, if a request for more memory is sent, a port is opened with the microkernel and the request sent through. Once within the microkernel, the steps are similar to system calls. The rationale was that it would bring modularity in the system architecture, which would entail a cleaner system, easier to debug or dynamically modify, customizable to users' needs, and more performing. They are part of the operating systems like GNU Hurd, MINIX, MkLinux, QNX and Redox OS. Although microkernels are very small by themselves, in combination with all their required auxiliary code they are, in fact, often larger than monolithic kernels. Advocates of monolithic kernels also point out that the two-tiered structure of microkernel systems, in which most of the operating system does not interact directly with the hardware, creates a not-insignificant cost in terms of system efficiency. These types of kernels normally provide only the minimal services such as defining memory address spaces, inter-process communication (IPC) and the process management. The other functions such as running the hardware processes are not handled directly by microkernels. Proponents of micro kernels point out those monolithic kernels have the disadvantage that an error in the kernel can cause the entire system to crash. However, with a microkernel, if a kernel process crashes, it is still possible to prevent a crash of the system as a whole by merely restarting the service that caused the error.


title: Kernel (operating system)

text: Other services provided by the kernel such as networking are implemented in user-space programs referred to as "servers". Servers allow the operating system to be modified by simply starting and stopping programs. For a machine without networking support, for instance, the networking server is not started. The task of moving in and out of the kernel to move data between the various applications and servers creates overhead which is detrimental to the efficiency of micro kernels in comparison with monolithic kernels.


title: Kernel (operating system)

text: The disadvantages for microkernels are extremely context-based. As an example, they work well for small single-purpose (and critical) systems because if not many processes need to run, then the complications of process management are effectively mitigated.


title: Kernel (operating system)

text: A microkernel allows the implementation of the remaining part of the operating system as a normal application program written in a high-level language, and the use of different operating systems on top of the same unchanged kernel. It is also possible to dynamically switch among operating systems and to have more than one active simultaneously.


title: Kernel (operating system)

text: As the computer kernel grows, so grows the size and vulnerability of its trusted computing base; and, besides reducing security, there is the problem of enlarging the memory footprint. This is mitigated to some degree by perfecting the virtual memory system, but not all computer architectures have virtual memory support. To reduce the kernel's footprint, extensive editing has to be performed to carefully remove unneeded code, which can be very difficult with non-obvious interdependencies between parts of a kernel with millions of lines of code.


title: Kernel (operating system)

text: By the early 1990s, due to the various shortcomings of monolithic kernels versus microkernels, monolithic kernels were considered obsolete by virtually all operating system researchers. As a result, the design of Linux as a monolithic kernel rather than a microkernel was the topic of a famous debate between Linus Torvalds and Andrew Tanenbaum. There is merit on both sides of the argument presented in the Tanenbaum–Torvalds debate.


title: Kernel (operating system)

text: Monolithic kernels are designed to have all of their code in the same address space (kernel space), which some developers argue is necessary to increase the performance of the system. Some developers also maintain that monolithic systems are extremely efficient if well written. The monolithic model tends to be more efficient through the use of shared kernel memory, rather than the slower IPC system of microkernel designs, which is typically based on message passing.


title: Kernel (operating system)

text: The performance of microkernels was poor in both the 1980s and early 1990s. However, studies that empirically measured the performance of these microkernels did not analyze the reasons of such inefficiency. The explanations of this data were left to "folklore", with the assumption that they were due to the increased frequency of switches from "kernel-mode" to "user-mode", to the increased frequency of inter-process communication and to the increased frequency of context switches.


title: Kernel (operating system)

text: In fact, as guessed in 1995, the reasons for the poor performance of microkernels might as well have been: (1) an actual inefficiency of the whole microkernel "approach", (2) the particular "concepts" implemented in those microkernels, and (3) the particular "implementation" of those concepts. Therefore it remained to be studied if the solution to build an efficient microkernel was, unlike previous attempts, to apply the correct construction techniques.


title: Kernel (operating system)

text: On the other end, the hierarchical protection domains architecture that leads to the design of a monolithic kernel has a significant performance drawback each time there's an interaction between different levels of protection (i.e., when a process has to manipulate a data structure both in "user mode" and "supervisor mode"), since this requires message copying by value.


title: Kernel (operating system)

text: Hybrid kernels are used in most commercial operating systems such as Microsoft Windows NT 3.1, NT 3.5, NT 3.51, NT 4.0, 2000, XP, Vista, 7, 8, 8.1 and 10. Apple Inc's own macOS uses a hybrid kernel called XNU which is based upon code from OSF/1's Mach kernel (OSFMK 7.3) and FreeBSD's monolithic kernel. They are similar to micro kernels, except they include some additional code in kernel-space to increase performance. These kernels represent a compromise that was implemented by some developers to accommodate the major advantages of both monolithic and micro kernels. These types of kernels are extensions of micro kernels with some properties of monolithic kernels. Unlike monolithic kernels, these types of kernels are unable to load modules at runtime on their own. Hybrid kernels are micro kernels that have some "non-essential" code in kernel-space in order for the code to run more quickly than it would were it to be in user-space. Hybrid kernels are a compromise between the monolithic and microkernel designs. This implies running some services (such as the network stack or the filesystem) in kernel space to reduce the performance overhead of a traditional microkernel, but still running kernel code (such as device drivers) as servers in user space.


title: Kernel (operating system)

text: Many traditionally monolithic kernels are now at least adding (or else using) the module capability. The most well known of these kernels is the Linux kernel. The modular kernel essentially can have parts of it that are built into the core kernel binary or binaries that load into memory on demand. It is important to note that a code tainted module has the potential to destabilize a running kernel. Many people become confused on this point when discussing micro kernels. It is possible to write a driver for a microkernel in a completely separate memory space and test it before "going" live. When a kernel module is loaded, it accesses the monolithic portion's memory space by adding to it what it needs, therefore, opening the doorway to possible pollution. A few advantages to the modular (or) Hybrid kernel are:


title: Kernel (operating system)

text: Modules, generally, communicate with the kernel using a module interface of some sort. The interface is generalized (although particular to a given operating system) so it is not always possible to use modules. Often the device drivers may need more flexibility than the module interface affords. Essentially, it is two system calls and often the safety checks that only have to be done once in the monolithic kernel now may be done twice. Some of the disadvantages of the modular approach are:


title: Kernel (operating system)

text: A nanokernel delegates virtually all services including even the most basic ones like interrupt controllers or the timer to device drivers to make the kernel memory requirement even smaller than a traditional microkernel.


title: Kernel (operating system)

text: Exokernels are a still-experimental approach to operating system design. They differ from other types of kernels in limiting their functionality to the protection and multiplexing of the raw hardware, providing no hardware abstractions on top of which to develop applications. This separation of hardware protection from hardware management enables application developers to determine how to make the most efficient use of the available hardware for each specific program.


title: Kernel (operating system)

text: Exokernels in themselves are extremely small. However, they are accompanied by library operating systems (see also unikernel), providing application developers with the functionalities of a conventional operating system. This comes down to every user writing their own rest-of-the kernel from near scratch, which is a very-risky, complex and quite a daunting assignment - particularly in a time-constrained production-oriented environment, which is why exokernels have never caught on. A major advantage of exokernel-based systems is that they can incorporate multiple library operating systems, each exporting a different API, for example one for high level UI development and one for real-time control.


title: Kernel (operating system)

text: A multikernel operating system treats a multi-core machine as a network of independent cores, as if it were a distributed system. It does not assume shared memory but rather implements inter-process communications as message-passing. Barrelfish was the first operating system to be described as a multikernel.


title: Kernel (operating system)

text: Strictly speaking, an operating system (and thus, a kernel) is not "required" to run a computer. Programs can be directly loaded and executed on the "bare metal" machine, provided that the authors of those programs are willing to work without any hardware abstraction or operating system support. Most early computers operated this way during the 1950s and early 1960s, which were reset and reloaded between the execution of different programs. Eventually, small ancillary programs such as program loaders and debuggers were left in memory between runs, or loaded from ROM. As these were developed, they formed the basis of what became early operating system kernels. The "bare metal" approach is still used today on some video game consoles and embedded systems, but in general, newer computers use modern operating systems and kernels.


title: Kernel (operating system)

text: In 1969, the RC 4000 Multiprogramming System introduced the system design philosophy of a small nucleus "upon which operating systems for different purposes could be built in an orderly manner", what would be called the microkernel approach.


title: Kernel (operating system)

text: In the decade preceding Unix, computers had grown enormously in power to the point where computer operators were looking for new ways to get people to use their spare time on their machines. One of the major developments during this era was time-sharing, whereby a number of users would get small slices of computer time, at a rate at which it appeared they were each connected to their own, slower, machine.


title: Kernel (operating system)

text: The development of time-sharing systems led to a number of problems. One was that users, particularly at universities where the systems were being developed, seemed to want to hack the system to get more CPU time. For this reason, security and access control became a major focus of the Multics project in 1965. Another ongoing issue was properly handling computing resources: users spent most of their time staring at the terminal and thinking about what to input instead of actually using the resources of the computer, and a time-sharing system should give the CPU time to an active user during these periods. Finally, the systems typically offered a memory hierarchy several layers deep, and partitioning this expensive resource led to major developments in virtual memory systems.


title: Kernel (operating system)

text: The Commodore Amiga was released in 1985, and was among the first and certainly most successful home computers to feature an advanced kernel architecture. The AmigaOS kernel's executive component, "exec.library", uses a microkernel message-passing design, but there are other kernel components, like "graphics.library", that have direct access to the hardware. There is no memory protection, and the kernel is almost always running in user mode. Only special actions are executed in kernel mode, and user-mode applications can ask the operating system to execute their code in kernel mode.


title: Kernel (operating system)

text: During the design phase of Unix, programmers decided to model every high-level device as a file, because they believed the purpose of computation was data transformation.


title: Kernel (operating system)

text: For instance, printers were represented as a "file" at a known location when data was copied to the file, it printed out. Other systems, to provide a similar functionality, tended to virtualize devices at a lower level that is, both devices "and" files would be instances of some lower level concept. Virtualizing the system at the file level allowed users to manipulate the entire system using their existing file management utilities and concepts, dramatically simplifying operation. As an extension of the same paradigm, Unix allows programmers to manipulate files using a series of small programs, using the concept of pipes, which allowed users to complete operations in stages, feeding a file through a chain of single-purpose tools. Although the end result was the same, using smaller programs in this way dramatically increased flexibility as well as ease of development and use, allowing the user to modify their workflow by adding or removing a program from the chain.


title: Kernel (operating system)

text: In the Unix model, the "operating system" consists of two parts: first, the huge collection of utility programs that drive most operations; second, the kernel that runs the programs. Under Unix, from a programming standpoint, the distinction between the two is fairly thin; the kernel is a program, running in supervisor mode, that acts as a program loader and supervisor for the small utility programs making up the rest of the system, and to provide locking and I/O services for these programs; beyond that, the kernel didn't intervene at all in user space.


title: Kernel (operating system)

text: Over the years the computing model changed, and Unix's treatment of everything as a file or byte stream no longer was as universally applicable as it was before. Although a terminal could be treated as a file or a byte stream, which is printed to or read from, the same did not seem to be true for a graphical user interface. Networking posed another problem. Even if network communication can be compared to file access, the low-level packet-oriented architecture dealt with discrete chunks of data and not with whole files. As the capability of computers grew, Unix became increasingly cluttered with code. It is also because the modularity of the Unix kernel is extensively scalable. While kernels might have had 100,000 lines of code in the seventies and eighties, kernels like Linux, of modern Unix successors like GNU, have more than 13 million lines.


title: Kernel (operating system)

text: Modern Unix-derivatives are generally based on module-loading monolithic kernels. Examples of this are the Linux kernel in the many distributions of GNU, IBM AIX, as well as the Berkeley Software Distribution variant kernels such as FreeBSD, DragonflyBSD, OpenBSD, NetBSD, and macOS. Apart from these alternatives, amateur developers maintain an active operating system development community, populated by self-written hobby kernels which mostly end up sharing many features with Linux, FreeBSD, DragonflyBSD, OpenBSD or NetBSD kernels and/or being compatible with them.


title: Kernel (operating system)

text: Apple first launched its classic Mac OS in 1984, bundled with its Macintosh personal computer. Apple moved to a nanokernel design in Mac OS 8.6. Against this, the modern macOS (originally named Mac OS X) is based on Darwin, which uses a hybrid kernel called XNU, which was created by combining the 4.3BSD kernel and the Mach kernel.


title: Kernel (operating system)

text: Microsoft Windows was first released in 1985 as an add-on to MS-DOS. Because of its dependence on another operating system, initial releases of Windows, prior to Windows 95, were considered an operating environment (not to be confused with an operating system). This product line continued to evolve through the 1980s and 1990s, with the Windows 9x series adding 32-bit addressing and pre-emptive multitasking; but ended with the release of Windows Me in 2000.


title: Kernel (operating system)

text: Microsoft also developed Windows NT, an operating system with a very similar interface, but intended for high-end and business users. This line started with the release of Windows NT 3.1 in 1993, and was introduced to general users with the release of Windows XP in October 2001—replacing Windows 9x with a completely different, much more sophisticated operating system. This is the line that continues with Windows 11.


title: Kernel (operating system)

text: The architecture of Windows NT's kernel is considered a hybrid kernel because the kernel itself contains tasks such as the Window Manager and the IPC Managers, with a client/server layered subsystem model. It was designed as a modified microkernel, as the Windows NT kernel was influenced by the Mach microkernel but does not meet all of the criteria of a pure microkernel.


title: Kernel (operating system)

text: Supervisory program or supervisor is a computer program, usually part of an operating system, that controls the execution of other routines and regulates work scheduling, input/output operations, error actions, and similar functions and regulates the flow of work in a data processing system.


title: Kernel (operating system)

text: Historically, this term was essentially associated with IBM's line of mainframe operating systems starting with OS/360. In other operating systems, the supervisor is generally called the kernel.


title: Kernel (operating system)

text: In the 1970s, IBM further abstracted the supervisor state from the hardware, resulting in a hypervisor that enabled full virtualization, i.e. the capacity to run multiple operating systems on the same machine totally independently from each other. Hence the first such system was called "Virtual Machine" or "VM".


title: Kernel (operating system)

text: Although Mach, developed by Richard Rashid at Carnegie Mellon University, is the best-known general-purpose microkernel, other microkernels have been developed with more specific aims. The L4 microkernel family (mainly the L3 and the L4 kernel) was created to demonstrate that microkernels are not necessarily slow. Newer implementations such as Fiasco and Pistachio are able to run Linux next to other L4 processes in separate address spaces.


title: Kernel (operating system)

text: Additionally, QNX is a microkernel which is principally used in embedded systems, and the open-source software MINIX, while originally created for educational purposes, is now focused on being a highly reliable and self-healing microkernel OS.


title: Nancy Drew (2019 TV series)

text: Nancy Drew is an American mystery drama television series based on the series of mystery novels about the titular character. The series was adapted for The CW by Noga Landau, Josh Schwartz and Stephanie Savage, and is produced by CBS Studios, in association with Fake Empire.


title: Nancy Drew (2019 TV series)

text: It is the third "Nancy Drew" television series, following "The Hardy Boys/Nancy Drew Mysteries" (1977–1979) and a 1995 Canadian-American version. Development for a new television series started in 2015 at CBS, then later at NBC. In 2018, the project moved to The CW where the series was ordered for a pilot.


title: Nancy Drew (2019 TV series)

text: The series is narrated and led by the amateur sleuth Nancy Drew, played by Kennedy McMann, and features an ensemble cast with re-imagined versions of the characters from the books: Leah Lewis as George Fan, Maddison Jaizani as Bess Marvin, Tunji Kasim as Ned Nickerson, and Alex Saxon as Ace. It also stars Scott Wolf as Carson Drew, Alvina August and Riley Smith as new characters invented for the series.


title: Nancy Drew (2019 TV series)

text: The series debuted on October 9, 2019, to mixed reviews. In October 2019, The CW picked up the series for a full season and in January 2020, the network renewed the series for a second season which premiered on January 20, 2021. In February 2021, the series was renewed for a third season which premiered on October 8, 2021. In March 2022, the series was renewed for a fourth and final season.


title: Nancy Drew (2019 TV series)

text: After putting off applying to Columbia University to deal with the loss of her mother, eighteen-year-old Nancy Drew gets entangled in the investigation of town socialite Tiffany Hudson's murder. Alongside the employees of the Claw, the restaurant she works at — prickly manager George Fan, worldly and polished waitress Bess Marvin, laidback dishwasher Ace, and mechanic Ned "Nick" Nickerson, whom she is having a no strings attached fling with — they reluctantly ally to clear their names of suspicion. With secrets they're all determined to keep hidden, not only is Nancy determined to unveil them in order to trust them, she unearths a connection to Tiffany's homicide to a decade-long cold case turned urban legend.


title: Nancy Drew (2019 TV series)

text: In September 2018, The CW announced that Josh Schwartz and Stephanie Savage were developing a new "Nancy Drew" series. The CW announced that the project was picked up for series on May 7, 2019. On May 16, 2019, The CW released the first official trailer for the series. The series debuted on October 9, 2019. On October 25, 2019, the series was picked up for a full season of 22 episodes. On January 7, 2020, the series was renewed for a second season which premiered on January 20, 2021. On February 3, 2021, The CW renewed the series for a third season which premiered on October 8, 2021. On March 22, 2022, The CW renewed the series for a fourth season. It announced later in October 2022 that the fourth season would be the final season of the show.


title: Nancy Drew (2019 TV series)

text: In early 2019, the pilot was cast with Kennedy McMann as the title character, Tunji Kasim as Ned "Nick" Nickerson, Alex Saxon as Ace, Leah Lewis as George, Maddison Jaizani as Bess, and Freddie Prinze Jr. as Nancy's father, Carson Drew. Pamela Sue Martin, who played Nancy Drew in the 1970s series "The Hardy Boys/Nancy Drew Mysteries", was cast as Harriet Grosset for the pilot in April 2019. On May 9, 2019, it was announced that Scott Wolf had replaced Prinze in the role of Carson Drew. Riley Smith joined cast as Ryan Hudson on May 16, 2019. On October 28, 2019, Miles Gaston Villanueva was cast in a recurring role.


title: Nancy Drew (2019 TV series)

text: In December 2020, Aadila Dosani was cast in a recurring role for the second season as Amanda Bobbsey. Her twin brother, Gil Bobbsey, is portrayed by Praneet Akilla.


title: Nancy Drew (2019 TV series)

text: Principal photography for the first season began on July 22, 2019, and was expected to end on April 7, 2020, in Vancouver, British Columbia. On March 12, 2020, production was halted until further notice due to the COVID-19 pandemic. However, on April 14, 2020, it was revealed that episode 18 would serve as the season one finale. The second season began filming on September 29, 2020. However, due to COVID-19 testing, filming was stopped shortly after and resumed a week later. Production of the second season ended on April 29, 2021. The third season began production on July 13, 2021, and concluded on December 9, 2021. Filming for the fourth season began on July 19, 2022, and is scheduled to conclude on December 15, 2022.


title: Nancy Drew (2019 TV series)

text: "Nancy Drew" premiered on The CW in the United States on Wednesday, October 9, 2019, with the season four premiere of "Riverdale" as its lead-in. In Canada, "Nancy Drew" was televised on the W Network and in Malaysia, "Nancy Drew" was televised on the PRIMEtime.


title: Nancy Drew (2019 TV series)

text: HBO Max and Paramount+ (formerly CBS All Access) acquired the streaming rights to the series in the United States, with seasons available on their platforms several days after the season finale airs.


title: Nancy Drew (2019 TV series)

text: On review aggregator Rotten Tomatoes, "Nancy Drew" holds an approval rating of 53% based on 30 reviews, with an average rating of 7.31/10. The website's critical consensus reads, "An appealing aesthetic and promising ensemble can't quite manage to liven up "Nancy Drew", an overly broody and unfortunately bland mystery that follows too closely in the footsteps of the shows it aspires to be." On Metacritic, it has a weighted average score of 55 out of 100, based on 12 critics, indicating "mixed or average reviews".


title: Nancy Drew (2019 TV series)

text: On March 31, 2020, the first tie-in novel for the show was published. Entitled "Nancy Drew: The Curse" it was written by Micol Ostow and served as a prequel to the show's events.


title: Nancy Drew (2019 TV series)

text: On October 28, 2020, it was announced that The CW is developing a spin-off titled "Tom Swift". The series is based on the book series of the same name and is created by Melinda Hsu Taylor, Noga Landau, and Cameron Johnson. On January 26, 2021, Tian Richards was cast in the titular role. On February 8, 2021, it was announced that Ruben Garcia would be directing the pilot episode. On May 11, 2021, LeVar Burton joined the main cast to voice an AI named Barclay. On August 30, 2021, "Tom Swift" was ordered straight-to-series and is expected to debut during the 2021–22 television season. In February 2022, Ashleigh Murray joined the cast as Zenzi Fullington. Later that month, Marquise Vilsón, April Parker Jones, and Albert Mwangi joined the regular cast in the roles of Isaac Vega, Lorraine Swift, and Rowan, respectively. In March 2022, Ward Horton was cast in a recurring role. The same month, the series was given a May 31, 2022, premiere date.


title: Sandy Koufax

text: Sanford Koufax (; born Sanford Braun; December 30, 1935) is an American former left-handed pitcher in Major League Baseball (MLB) who played his entire career for the Brooklyn/Los Angeles Dodgers from 1955 to 1966. He has been hailed as one of the greatest pitchers in baseball history. After joining the major leagues at age 19, having never pitched a game in the minor leagues, the first half of his career was unremarkable, posting a record of just 36–40 with a 4.10 earned run average (ERA); he was a member of World Series champions in both Brooklyn and Los Angeles, though he did not appear in any of the team's Series wins. But after making adjustments prior to the 1961 season, and benefitting from the team's move into expansive Dodger Stadium a year later, Koufax quickly rose to become the most dominant pitcher in the major leagues before arthritis in his left elbow ended his playing days prematurely at age 30.


title: Sandy Koufax

text: Koufax was an All-Star in each of his last six seasons, leading the National League (NL) in ERA each of his last five years, in strikeouts four times, in wins and shutouts three times each, and in winning percentage, innings pitched and complete games twice each; he was the first NL pitcher in 20 years to post an ERA below 2.00, doing so three times. After setting a modern NL record in with 269 strikeouts, in he became the first pitcher in 17 years and the first left-hander since 1904 to strike out 300 batters. In he set a major league record with 382 strikeouts; it was broken in 1973 by Nolan Ryan, but remains the top mark for NL pitchers and left-handers. He was the first pitcher to record 300 strikeouts three times, and set a record with 97 games of at least 10 strikeouts, also later broken by Ryan; he twice tied a modern record by striking out 18 batters in a game. Koufax won the Cy Young Award in 1963, 1965 and by unanimous votes, winning the Triple Crown and leading the Dodgers to a pennant each year; he was the first three-time winner of the award, and the only pitcher to do so when a single award was given instead of one for each league. He was also named the NL Most Valuable Player (MVP) in 1963, and was runner-up for the award the other two years.


title: Sandy Koufax

text: Koufax was the first major league pitcher to hurl four no-hitters, and in 1965 became the eighth pitcher and the first left-hander since 1880 to pitch a perfect game. He was named the World Series MVP in both 1963 and 1965, earning two wins in each Series and striking out 52 batters to lead the team to another pair of titles. He is also notable for being one of the outstanding Jewish athletes in U.S. sports; Koufax's decision not to pitch Game 1 of the 1965 World Series because it fell on the Jewish holiday Yom Kippur garnered national attention as a conflict between religious calling and society, and remains a notable event in U.S. Jewish history. Upon his retirement, Koufax's career ERA of 2.76 trailed only Whitey Ford among pitchers with at least 2,000 innings pitched since 1925; his .655 winning percentage ranked third among both left-handers and modern NL pitchers. Despite his comparatively short career, his 2,396 career strikeouts ranked seventh in major league history, trailing only Warren Spahn (2,583) among left-handers; his 40 shutouts were tied for ninth in modern NL history. He was the first pitcher in history to average more than one strikeout per inning, and the first to allow fewer than seven hits per nine innings pitched. Koufax briefly held the Dodgers records for career strikeouts and shutouts until longtime teammate Don Drysdale passed him in 1968. Koufax was inducted into the Baseball Hall of Fame in his first year of eligibility in 1972, becoming at age 36 the youngest player ever elected. He has since worked for the Dodgers organization in a variety of capacities.


title: Sandy Koufax

text: Koufax was born in Brooklyn, New York, to a Jewish family and was raised in Borough Park. His parents, Evelyn (née Lichtenstein) and Jack Braun, divorced when he was three years old. His mother was remarried when he was nine, to Irving Koufax. Shortly after his mother's remarriage, the family moved to the Long Island suburb of Rockville Centre. Before tenth grade, Koufax's family moved back to the Bensonhurst section of Brooklyn.


title: Sandy Koufax

text: Koufax attended Brooklyn's Lafayette High School, where he was better known for basketball than for baseball. He started playing basketball for the Edith and Carl Marks Jewish Community House of Bensonhurst local community center team. Eventually, Lafayette had a basketball team; Koufax became team captain in his senior year, and ranked second in his division in scoring, with 165 points in 10 games. In 1951, at the age of 15, Koufax also joined a local youth baseball league known as the "Ice Cream League". He started out as a left-handed catcher before moving to first base. While playing first base for Lafayette's baseball team with his friend Fred Wilpon, he was spotted by Milt Laurie, a baseball coach who was the father of two Lafayette players. Laurie recognized that Koufax might be able to pitch, and recruited the 17-year-old to pitch for the Coney Island Sports League's Parkviews.


title: Sandy Koufax

text: Koufax attended the University of Cincinnati and was a walk-on on the freshman basketball team, a complete unknown to assistant coach Ed Jucker. He later earned a partial scholarship. In spring 1954, he made the college baseball varsity team, which was coached by Jucker at that time. In his only season, Koufax went 3–1 with a 2.81 ERA, 51 strikeouts and 30 walks in 32 innings. Bill Zinser, a scout for the Brooklyn Dodgers, sent the Dodgers front office a glowing report that apparently was filed and forgotten.


title: Sandy Koufax

text: After trying out with the New York Giants at the Polo Grounds, Koufax did the same for the Pittsburgh Pirates at Forbes Field. During his Pirates tryout, his fastball broke the thumb of Sam Narron, the team's bullpen coach. Branch Rickey, then the general manager of the Pirates, told his scout Clyde Sukeforth that Koufax had the "greatest arm [he had] ever seen". The Pirates, however, failed to offer Koufax a contract until after he was already committed to the Dodgers. Dodgers scout Al Campanis heard about Koufax from Jimmy Murphy, a part-time scout. After seeing Koufax pitch for Lafayette, Campanis invited him to an Ebbets Field tryout. With Dodgers manager Walter Alston and scouting director Fresco Thompson watching, Campanis assumed the hitter's stance while Koufax started throwing. Campanis later said, "There are two times in my life the hair on my arms has stood up: The first time I saw the ceiling of the Sistine Chapel and the second time, I saw Sandy Koufax throw a fastball." The Dodgers signed Koufax for a $6,000 ($ today) salary, with a $14,000 ($ today) signing bonus. Koufax planned to use the money as tuition to finish his university education, if his baseball career failed.


title: Sandy Koufax

text: Because Koufax's signing bonus was greater than $4,000 ($ today), he was known as a bonus baby. This forced the Dodgers to keep him on the major league roster for at least two years before he could be sent to the minors. To make room for him, the Dodgers optioned their future Hall of Fame manager, Tommy Lasorda, to the Montreal Royals of the International League. Lasorda would later joke that it took Koufax to keep him off the Dodger pitching staff.


title: Sandy Koufax

text: Koufax made his major league debut on June 24, , against the Milwaukee Braves, with the Dodgers trailing 7–1 in the fifth inning. Johnny Logan, the first batter Koufax faced, hit a bloop single. Eddie Mathews bunted, and Koufax threw the ball into center field. He then walked Hank Aaron on four pitches to load the bases, but struck out Bobby Thomson on a 3–2 fastball—an outcome Koufax later came to view as "probably the worst thing that could have happened to me," leading, as it did, to five seasons spent "trying to get out of trouble by throwing harder and harder and harder."


title: Sandy Koufax

text: Koufax's first start was on July 6. He lasted only innings, giving up eight walks. He did not start again for almost two months, but on August 27, Koufax threw a two-hit, 7–0 complete game shutout against the Cincinnati Reds for his first major league win. Koufax threw innings in 12 appearances that season, striking out 30 batters and walking 28. He had two wins in 1955, which were both shutouts.


title: Sandy Koufax

text: During the fall, he enrolled in the Columbia University School of General Studies, which offered night classes in architecture. The Dodgers won the 1955 World Series for the first title in franchise history, but Koufax did not appear in the series. After the final out of Game 7, Koufax drove to Columbia to attend class.


title: Sandy Koufax

text: The year 1956 was not very different from 1955 for Koufax. Despite the blazing speed of his fastball, Koufax continued to struggle with his control. He saw little work, pitching only innings with a 4.91 ERA, 29 walks and 30 strikeouts. When Koufax allowed baserunners, he was rarely permitted to finish the inning. Teammate Joe Pignatano said that as soon as Koufax threw a couple of balls in a row, Alston would signal for a replacement to start warming up in the bullpen. Jackie Robinson, in his final season, clashed with Alston on Koufax's usage. Robinson saw that Koufax was talented and had flashes of brilliance, and objected to him being benched for weeks at a time.


title: Sandy Koufax

text: To prepare for the season, the Dodgers sent Koufax to Puerto Rico to play winter ball. On May 15, the restriction on sending Koufax down to the minors was lifted. Alston gave him a chance to justify his place on the major league roster by giving him the next day's start. Facing the Chicago Cubs at Wrigley Field, Koufax struck out 13 while pitching his first complete game in almost two years. For the first time in his career, he was in the starting rotation, but only for two weeks. Despite winning three of his next five with a 2.90 ERA, Koufax did not get another start for 45 days. In that start, he struck out 11 in seven innings, but got no decision. On September 29, he became the last man to pitch for the Brooklyn Dodgers before their move to Los Angeles, throwing an inning of relief in the final game of the season.


title: Sandy Koufax

text: Koufax and fellow Dodgers pitcher Don Drysdale served six months in the United States Army Reserve at Fort Dix in New Jersey after the end of the 1957 season and before spring training in 1958.


title: Sandy Koufax

text: Over the next three seasons, Koufax was in and out of the starting rotation due to injuries. In 1958, he began 7–3, but sprained his ankle in a collision at first base, finishing the season at 11–11 and leading the NL in wild pitches. In June 1959, Koufax set the record for a night game with 16 strikeouts. On August 31 against the Giants, he set the NL single-game record and tied Bob Feller's modern major league record of 18, also scoring on Wally Moon's walk-off home run for a 5-2 win.


title: Sandy Koufax

text: In , the Dodgers won a close pennant race against the Braves and the Giants, then beat the Chicago White Sox in the World Series. Koufax pitched two perfect relief innings in the Series opener, though they came after the Dodgers were already behind 11–0. Alston gave him the start in Game 5, at the Los Angeles Coliseum in front of 92,706 fans. Koufax allowed only one run in seven innings, but lost the 1–0 game when Nellie Fox scored on a double play. Returning to Chicago, the Dodgers won Game 6 and the Series.


title: Sandy Koufax

text: In early , Koufax asked Dodgers general manager Buzzie Bavasi to trade him because he was not getting enough playing time. On May 23, he pitched a 1-0, one-hit shutout in Pittsburgh, allowing only a second-inning single by pitcher Bennie Daniels. By the end of the year, after going 8–13, Koufax was thinking about quitting baseball to devote himself to an electronics business in which he had invested. After the last game of the season, he threw his gloves and spikes into the trash. Nobe Kawano, the clubhouse supervisor, retrieved the equipment in case Koufax returned to play the following year.


title: Sandy Koufax

text: Koufax tried one more year of baseball, showing up for the 1961 season in better condition than he ever had before. Years later he recalled, "That winter was when I really started working out. I started running more. I decided I was really going to find out how good I can be." During spring training, Dodger scout Kenny Myers discovered a hitch in Koufax's windup, where he would rear back so far he would lose sight of the target.


title: Sandy Koufax

text: A day later, Koufax was pitching for the "B team" in Orlando. Teammate Ed Palmquist missed the flight, so Koufax was told he would need to pitch at least seven innings. In the first inning, Koufax walked the bases loaded on 12 straight pitches. Catcher Norm Sherry advised him to throw slightly less hard in order to improve his control. The advice worked, Koufax struck out the side, and then went on to pitch seven no-hit innings.


title: Sandy Koufax

text: In perhaps an early display of sabermetrics, Dodger statistician Allan Roth is credited with helping Koufax tweak his game in the early 1960s, particularly regarding the importance of first-pitch strikes and the benefits of off-speed pitches.


title: Sandy Koufax

text: 1961 was Koufax's breakout season. He posted an 18–13 record and led the league with 269 strikeouts, breaking Christy Mathewson's 58-year-old NL mark of 267. Selected as an All-Star for the first time, he appeared in both All-Star Games that year (two All-Star games were held for the years from 1959 to 1962). In the first game he faced only one batter, giving up a hit to Al Kaline in the ninth inning. In the second game, he pitched two scoreless innings.


title: Sandy Koufax

text: In , the Dodgers moved from the Los Angeles Coliseum, which had a left-field line – an enormous disadvantage to lefthanded pitchers – to pitcher-friendly Dodger Stadium. The new park had a large foul territory and a comparatively poor hitting background. Koufax was an immediate beneficiary of the change, lowering his ERA at home from 4.29 to 1.75. On April 24, he tied his own record with 18 strikeouts in a 10-2 road win over the Cubs. On June 13 in Milwaukee, Koufax hit the first home run of his career off Warren Spahn, providing the winning margin in a 2-1 victory in Milwaukee. On June 30 against the expansion New York Mets, he threw his first no-hitter. In the first inning of that game he struck out all three batters on nine total pitches to become the sixth recorded National League pitcher and the 11th recorded pitcher in major league history to accomplish an immaculate inning. His no-hitter, along with a 4–2 record, 73 strikeouts and a 1.23 ERA, earned him the Player of the Month Award for June. It would be the only time in his career he earned this distinction.


title: Sandy Koufax

text: Koufax had a strong season despite an injured pitching hand. While batting in April, he had been jammed by a pitch from Earl Francis. A numbness developed in the index finger on his left hand, and the finger became cold and white. Koufax was pitching better than ever, however, so he ignored the problem, hoping that the condition would clear up. By July, though, his entire hand was becoming numb and he was unable to complete some games. In a start in Cincinnati his finger split open after one inning. A vascular specialist determined that Koufax had a crushed artery in his palm. Ten days of experimental medicine successfully reopened the artery. Koufax finally was able to pitch again in September, when the team was locked in a tight pennant race with the Giants. But after the long layoff, Koufax was ineffective in three appearances as the Giants caught the Dodgers at the end of the regular season, forcing a three-game playoff.


title: Sandy Koufax

text: The night before the playoffs began, manager Alston asked Koufax if he could start the next day. With an overworked pitching staff there was no one else, as Drysdale and Johnny Podres had pitched the prior two days. Koufax obliged. Koufax later said, "I had nothing at all." He was knocked out in the second inning, after giving up home runs to future Hall of Famer Willie Mays and Jim Davenport. After winning the second game of the series, the Dodgers blew a 4–2 lead in the ninth inning of the deciding third game, losing the pennant.


title: Sandy Koufax

text: In 1963 Major League Baseball expanded the strike zone. Compared to the previous season, walks in the NL fell 13 percent, strikeouts increased 6 percent, the league batting average fell from .261 to .245, and runs scored declined 15 percent. Koufax, who had reduced his walks allowed per nine innings to 3.4 in 1961 and 2.8 in 1962, reduced his walk rate further to 1.7 in 1963, which ranked fifth in the league. The top pitchers of the era – future Hall of Famers Drysdale, Juan Marichal, Jim Bunning, Bob Gibson, Warren Spahn - and above all Koufax – significantly reduced the walks-given-up-to-batters-faced ratio for 1963 and subsequent years.


title: Sandy Koufax

text: On May 11 Koufax no-hit the Giants 8–0, besting Marichal—himself a no-hit pitcher on June 15. Koufax carried a perfect game into the eighth inning against the powerful Giants lineup, including Mays and fellow future Hall of Famers Willie McCovey and Orlando Cepeda. He walked Ed Bailey on a 3-and-2 pitch in the eighth, and pinch-hitter McCovey on four pitches in the ninth, before closing out the game. From July 3 to July 16, he pitched 33 consecutive scoreless innings, pitching three shutouts to lower his ERA to 1.65. On July 20 he hit the second and last home run of his career, coincidentally again in Milwaukee, a three-run shot to propel the team to a 5-4 win; it was his only game with three runs batted in. The Dodgers won the pennant, and Koufax won the first of three pitchers' Triple Crowns, leading the league in wins (25), strikeouts (306) and ERA (1.88). He threw 11 shutouts, eclipsing Carl Hubbell's 30-year post-1900 mark for a left-handed pitcher of 10 and setting a record that stands to this day. Only St. Louis Cardinal Bob Gibson, with 13 in his iconic 1968 season, "the year of the pitcher", has thrown more.


title: Sandy Koufax

text: Koufax won the NL MVP Award and the Hickok Belt, and was the first-ever unanimous selection for the Cy Young Award. It was not only the first of three times he would be a unanimous selection, it was the only Cy Young Award given out for both leagues during his career; separate awards for each league were presented starting in 1967.


title: Sandy Koufax

text: Facing the Yankees in the 1963 World Series, Koufax beat Whitey Ford 5–2 in Game 1 and struck out the first five batters and 15 overall, breaking Carl Erskine's decade-old record of 14 (a record that would fall to Gibson's 17 in the 1968 World Series opener). After seeing Koufax's Game 1 performance, Yankee Yogi Berra said, "I can see how he won 25 games. What I don't understand is how he lost five," to which Dodger shortstop Maury Wills responded, "He didn't. We lost them for him." In Game 4, Koufax completed the Dodgers' series sweep with a 2–1 victory over Ford, clinching the Series MVP Award for his performance.


title: Sandy Koufax

text: Koufax's season started with great expectations. On April 18, he struck out three batters on nine pitches in the third inning of a 3–0 loss to the Cincinnati Reds, becoming the only NL pitcher to have two "immaculate innings". On April 22, however, "he felt something let go in his arm," resulting in three cortisone shots for a sore elbow and three missed starts.


title: Sandy Koufax

text: On June 4, playing at Connie Mack Stadium against the Philadelphia Phillies, Koufax walked Richie Allen on a very close full-count pitch in the fourth inning. Allen, who was thrown out trying to steal second, was the only Phillie to reach base that day. With his third no-hitter in three years Koufax tied Feller as the only modern-era pitchers to hurl three no-hitters.


title: Sandy Koufax

text: Koufax jammed his pitching arm in August while diving back to second base to beat a pick-off throw. He managed to pitch and win two more games. However, the morning after his 19th win, a shutout in which he struck out 13 batters, he could not straighten his arm. He was diagnosed by Dodgers team physician Robert Kerlan with traumatic arthritis. With the Dodgers out of the pennant race he did not pitch again, ending the season with a 19–5 record and leading the NL with a 1.74 ERA.


title: Sandy Koufax

text: The 1965 season brought more obstacles for Koufax. On March 31, the morning after pitching a complete spring training game, Koufax awoke to find that his entire left arm was black and blue from hemorrhaging. Koufax returned to Los Angeles to consult with Kerlan, who advised him that he would be lucky to be able to pitch once a week. Kerlan also told Koufax that he would eventually lose full use of his arm. Koufax agreed not to throw at all between games—a resolution that lasted only one start. To get himself through the games he pitched, Koufax resorted to Empirin with codeine for the pain, which he took every night and sometimes during the fifth inning. He also took Butazolidin for inflammation, applied capsaicin-based Capsolin ointment (also sold by the brand name "Atomic Balm") before each game, and soaked his arm in a tub of ice afterwards.


title: Sandy Koufax

text: On June 20, in the first game of a doubleheader against the Mets, Koufax pitched his second one-hitter, allowing only a fifth-inning home run by Jim Hickman before the Dodgers came back for a 2-1 win. Despite the constant pain in his pitching elbow, he pitched a major league-leading innings and led the Dodgers to another pennant. Koufax won his second pitchers' Triple Crown, leading the league in wins (26), ERA (2.04) and strikeouts (382, the highest modern-day total at the time, topped only by Nolan Ryan's 383 in ), and captured his second unanimous Cy Young Award. He held batters to 5.79 hits per nine innings, and allowed the fewest baserunners per nine innings in any season ever: 7.83, breaking his own record (set two years earlier) of 7.96. Koufax had 11-game winning streaks in both 1964 and 1965.


title: Sandy Koufax

text: On September 9, 1965, Koufax became the sixth pitcher of the modern era, and eighth overall, to throw a perfect game. The game was Koufax's fourth no-hitter, setting a major league record (subsequently broken by Ryan in 1981), and the first by a left-hander since 1880. He struck out 14 batters in the 1–0 win, at the time the most recorded in a perfect game (tied by Matt Cain in 2012). The game also set a record for the fewest hits ever in a major league contest, thanks to a one-hitter thrown by the opposing pitcher, Bob Hendley of the Cubs, who only allowed only two batters to reach base. Both pitchers had no-hitters intact until the seventh inning.


title: Sandy Koufax

text: The winning run was unearned, scored without a hit when the Dodger's Lou Johnson walked, reached second on a sacrifice, stole third, and scored on a throwing error by Chicago catcher Chris Krug.


title: Sandy Koufax

text: Koufax declined to pitch Game 1 of the 1965 World Series in order to observe the Jewish religious holiday of Yom Kippur. His decision garnered national headlines, raising the conflict between professional pressures and personal religious beliefs to front-page news. Drysdale pitched the opener, but was hit hard by the Minnesota Twins.


title: Sandy Koufax

text: In Game 2 Koufax pitched six innings, giving up two runs, and the Twins won 5–1 to take an early 2–0 lead in the series. The Dodgers fought back in Games 3 and 4, with wins by Claude Osteen and Drysdale. With the Series tied at 2–2, Koufax pitched a complete-game shutout in Game 5 for a 3–2 Dodgers lead as the Series returned to Metropolitan Stadium for Game 6, which the Twins won to force a seventh game. Starting Game 7 on just two days of rest, Koufax pitched through fatigue and arthritic pain. Despite giving up on his curveball early in the game after failing to throw strikes with it in the first two innings, and pitching the rest of the game relying almost entirely on fastballs, Koufax threw a three-hit shutout to clinch the Series. The performance earned him his second World Series MVP award, making him the first player to win the award twice. Koufax also won the Hickok Belt a second time, the first time anyone had won the belt more than once. He was awarded "Sports Illustrated" magazine's Sportsman of the Year award.


title: Sandy Koufax

text: Before the 1966 season began, Koufax and Drysdale met separately with general manager Buzzie Bavasi to negotiate their contracts for the upcoming year. After the meeting, the pitchers met for dinner, with Koufax complaining that Bavasi was using his teammate against him in the negotiations, taunting, "How come you want that much when Drysdale only wants this much?" Drysdale responded that Bavasi had done the same thing with him, in reverse. Drysdale's wife Ginger suggested that they negotiate together to get what they wanted. They demanded $1 million (equivalent to $ million in ), divided equally over the next three years, or $167,000 (equivalent to $ million in ) each for each of the next three seasons. Both players were represented by an entertainment lawyer, J. William Hayes, which was unusual in an era when players were not even represented by agents. At the time, Willie Mays was the highest paid player in the major leagues at $125,000 (equivalent to $ million in ) per year, and multi-year contracts were extremely unusual.


title: Sandy Koufax

text: Koufax and Drysdale did not report to spring training in February. Instead, both signed to appear in the movie "Warning Shot", starring David Janssen. Drysdale was to play a TV commentator and Koufax a detective. Meanwhile, the Dodgers waged a public relations battle against them. After four weeks, Koufax gave Drysdale the go-ahead to negotiate new deals for both of them. Koufax ended up getting $125,000 and Drysdale $110,000 (equivalent to $ million in ). They rejoined the team in the last week of spring training.


title: Sandy Koufax

text: In April 1966, Kerlan told Koufax it was time to retire and that his arm could not take another season. Koufax kept Kerlan's advice to himself and went out every fourth day to pitch. He ended up with a third pitcher's Triple Crown, pitching 323 innings, posting a 27–9 record, and recording a 1.73 ERA. Since then, no left-hander has had more wins, nor a lower ERA; only Phillies pitcher Steve Carlton matched the 27-win mark, in 1972. In the final game of the regular season, the Dodgers had to beat the Phillies to win the pennant. In the second game of a doubleheader, Koufax faced Jim Bunning for the second time that season, in a match-up between perfect game winners. On two days rest, Koufax pitched a 6-3 complete-game victory to clinch the pennant. He started 41 games (for the second year in a row); only two left-handers have started more games in any season over the ensuing years through 2021.


title: Sandy Koufax

text: The Dodgers went on to face the Baltimore Orioles in the World Series, and Game 2 marked Koufax's third start in eight days. He pitched well enough—Baltimore first baseman Boog Powell told Koufax's biographer, Jane Leavy, "He might have been hurtin' but he was bringin'"—but three errors by Dodger center fielder Willie Davis in the fifth inning produced three unearned runs. Baltimore's 20-year-old future Hall of Famer Jim Palmer pitched a four-hitter, and the Orioles won 6–0. Alston lifted Koufax at the end of the sixth with the idea of getting him extra rest before a potential fifth game. Instead, the Dodgers were swept in four games, not scoring a single run in the last In his three World Series losses, all starts, spread over three different Series, Koufax gave up a total of three earned runs; the Dodgers scored a total of one run in support in all three.


title: Sandy Koufax

text: Less than six weeks after the series, on Friday, Koufax announced his retirement due to an arthritic elbow.


title: Sandy Koufax

text: In his 12-season major league career, Koufax had a 165–87 record with a 2.76 ERA, 2,396 strikeouts, 137 complete games, and 40 shutouts. He was the first pitcher to average fewer than seven hits allowed per nine innings pitched (6.79) and to strike out more than nine batters (9.28) per nine innings pitched. He also became the second pitcher in baseball history to have two games with 18 or more strikeouts, and the first to have eight games with 15 or more strikeouts. In his last ten seasons, from 1957 to 1966, batters hit .203 against him, with a .271 on-base percentage and a .315 slugging average.


title: Sandy Koufax

text: Due to a lack of run support, Koufax's postseason won-lost record over four World Series is an unimpressive 4–3, but his historic 0.95 ERA and two World Series MVPs testify to how well he actually pitched. He remains, over half a century later, on the very short list of pitchers who retired with more career strikeouts than innings pitched. He was selected as an All-Star for six consecutive seasons and made seven out of eight possible All-Star Game appearances those seasons (he was not on the roster for the second All-Star Game in 1962). He pitched six innings in four All-Star games, including being the starting pitcher for three innings in the 1966 All-Star Game.


title: Sandy Koufax

text: Koufax was the first pitcher to win multiple Cy Young Awards, an especially impressive feat because it was during the era when only one was given out for both major leagues. He is also the first pitcher to win the award by a unanimous vote—a recognition which he accomplished twice more. Koufax and Juan Marichal are the only two pitchers to have more than one 25-win season in the post-World War II era, with each man recording three.


title: Sandy Koufax

text: Koufax threw with a pronounced straight-over-the-top arm action. This aided in his devastating curveball and may have increased his velocity, but reduced the lateral movement on his pitches, especially movement away from left-handed hitters. Most of his velocity came from his strong legs and back, combined with a high leg kick during his wind-up and long forward extension on his release point toward home plate. Throughout his career, Koufax relied heavily on two pitches. His four-seam fastball gave batters the impression of rising as it approached them, due to backspin. It not only appeared to move very late but also might move on multiple planes. His overhand curveball, spun with the middle finger, dropped vertically 12 to 24 inches due to his arm action. Sabermetrician Rob Neyer called it the best curve of all time. He also occasionally threw a changeup and a forkball.


title: Sandy Koufax

text: At the beginning of his career Koufax fought a tendency to "tip" pitches to the opposing team through variations in his wind-up, which included the position in which he held his hands at the top of the wind-up. When throwing a fastball with baserunners, his hand position in the stretch would be higher than when he threw a curveball. Once alerted, he made an effort to better disguise his deliveries. Late in his career, his tendency to tip pitches became even more pronounced. Good hitters could often predict what pitch was coming, but were still unable to hit it. Willie Mays said, "I knew every pitch he was going to throw – fastball, breaking ball or whatever. Actually, he would let you look at it. And you still couldn't hit it."


title: Sandy Koufax

text: In 1967, Koufax signed a 10-year contract with NBC for US$1 million (equivalent to $ million in ) to be a broadcaster on the "Saturday Game of the Week". He quit after six years, just prior to the start of the 1973 season.


title: Sandy Koufax

text: The Dodgers hired Koufax to be a minor league pitching coach in . He resigned in , saying he was not earning his keep, but most observers blamed it on his uneasy relationship with manager Tommy Lasorda. Koufax returned to the Dodger organization in when the Dodgers were sold to Frank McCourt. The Dodgers again hired Koufax in 2013 as a special advisor to team chairman Mark Walter to work with the pitchers during spring training and consult during the season.


title: Sandy Koufax

text: Koufax was elected to the Baseball Hall of Fame in his first year of eligibility, 1972, just weeks after his 36th birthday. He was the youngest player ever elected, five months younger than Lou Gehrig upon his special election in December 1939 (which waived what was then a one-year waiting period before enshrinement). However, due to changes in Hall practices, the 1972 induction ceremony was nearly eight months after the election, leaving Koufax slightly older than Gehrig, who had no formal induction ceremony, at the time of his induction. On June 4 of that year, Koufax's uniform number 32 was retired alongside those of Dodger greats Roy Campanella (39) and Jackie Robinson (42). In 2022, a statue of Koufax was unveiled at Dodger Stadium.


title: Sandy Koufax

text: In , "The Sporting News" placed Koufax at number 26 on its list of "Baseball's 100 Greatest Players". He was also named that year as one of the 30 players on the Major League Baseball All-Century Team. Although he rarely makes public appearances, he went to Turner Field in Atlanta for the introduction ceremony before Game 2 of the 1999 World Series.


title: Sandy Koufax

text: In 1990 Koufax was inducted into the Southern California Jewish Sports Hall of Fame. He was the final player chosen in the inaugural Israel Baseball League draft in April 2007, picked, at 71 years old, by the Modi'in Miracle. "His selection is a tribute to the esteem with which he is held by everyone associated with this league", said former New York Met Art Shamsky, who managed the Miracle. "It's been 41 years between starts for him. If he's rested and ready to take the mound again, we want him on our team." Koufax declined the offer.


title: Sandy Koufax

text: Before the 2015 MLB All-Star Game in Cincinnati, Koufax was introduced as one of the four best living players (as selected by fans), along with Willie Mays, Hank Aaron and Johnny Bench. He threw the ceremonial first pitch to Bench from in front of the base of the mound.


title: Sandy Koufax

text: Koufax was included among a group of prominent Jewish Americans honored at a May 27, 2010, White House reception for Jewish American Heritage Month. During welcome remarks in a reminiscence of Koufax's decision not to play on the Jewish holy day of Yom Kippur, President Barack Obama said that the two had "something in common." Obama continued: "He can't pitch on Yom Kippur. I can't pitch." Obama directly acknowledged the high esteem in which Koufax is held: "This is a ... pretty distinguished group," he said of the invited guests, which included members of the House and Senate, two justices of the Supreme Court, Olympic athletes, entrepreneurs, rabbinical scholars, "and Sandy Koufax." The mention of his name brought the biggest cheer at the event.


title: Sandy Koufax

text: Koufax has been described by "Sports Illustrated" writer John Rosengren as a secular Jew. Regardless, his decision to not pitch on Yom Kippur in 1965 was highly significant for Jewish-Americans. In addition, there were other Jewish holidays where he said he would not pitch, including Seder night of Passover and 3 times on Rosh Hashanah, one of which was Game 4 of the 1959 World Series.


title: Sandy Koufax

text: Author Larry Ruttman called Koufax "an icon" for Jewish people because of his pitching skill and what he called Koufax's "deep respect for his Judaism" as shown in 1965.


title: Sandy Koufax

text: Koufax married Anne Widmark, the daughter of actor Richard Widmark, in 1969; they divorced in 1982. His second marriage, to personal trainer Kimberly Francis, lasted from 1985 to 1998. Neither marriage produced children. His third wife is Jane Dee Purucker Clarke, a college sorority sister of First Lady Laura Bush. Koufax is the stepfather of Clarke's daughter from her prior marriage to artist John Clem Clarke.


title: Sandy Koufax

text: Koufax serves as a member of the advisory board of the Baseball Assistance Team, a non-profit organization dedicated to helping former major league, minor league, and Negro league players through financial and medical difficulties.


title: Louisa Harland

text: Louisa Clare Harland (born 1993 or 1994) is an Irish actress. She is best known for her role as Orla McCool in the Channel 4 sitcom "Derry Girls".


title: Louisa Harland

text: Born in Dublin to a Northern Irish father, Harland has two older sisters, Katie and Ellie. She was part of the Ann Kavanagh Youth Theatre in Rathfarnham. She trained at the Mountview Academy of Theatre Arts in London.


title: Louisa Harland

text: Upon graduation, Harland landed a recurring role as Kayleigh in the RTÉ One series "Love/Hate" in 2011. She later appeared in films Rob Burke's "Standby" (2014) and Woody Harrelson's "Lost in London" (2017).


title: Louisa Harland

text: In 2017, it was announced Harland had been cast as Orla McCool, the eccentric cousin of Erin Quinn (Saoirse-Monica Jackson), in the Channel 4 sitcom "Derry Girls". The first series aired in January 2018, receiving critical and commercial acclaim, and the second in March 2019.


title: Louisa Harland

text: On 26 June 2020, Harland and her fellow "Derry Girls" costars performed a sketch with Saoirse Ronan for the RTÉ fundraising special "RTÉ Does Comic Relief", with proceeds from the night going towards those affected by the COVID-19 pandemic.


title: Louisa Harland

text: In March 2021, Harland performed with Sam Otto in an adaptation of the play "Endless Second", by Theo Toksvig-Stewart, for BBC Radio 4. That May, she performed in an adaptation of the debut novel "Snowflake", by Louise Nealon, for BBC Radio 4.


title: Hugh Glass

text: Hugh Glass ( 1783 – 1833) was an American frontiersman, fur trapper, trader, hunter and explorer. He is best known for his story of survival and forgiveness after being left for dead by companions when he was mauled by a grizzly bear.


title: Hugh Glass

text: No records exist regarding his origins but he is widely said to have been born in Pennsylvania to Scottish, possibly Scots-Irish, parents. Glass became an explorer of the watershed of the Upper Missouri River, in present-day Montana, the Dakotas, and the Platte River area of Nebraska. His life story has been the basis of two feature-length films: "Man in the Wilderness" (1971) and "The Revenant" (2015). They both portray the survival struggle of Glass, who (in the best historical accounts) crawled and stumbled to Fort Kiowa, South Dakota, after being abandoned without supplies or weapons by fellow explorers and fur traders during General Ashley's expedition of 1823. Another version of the story was told in a 1966 episode of the TV series "Death Valley Days", titled "Hugh Glass Meets the Bear".


title: Hugh Glass

text: Despite the story's popularity, its accuracy has been disputed. It was first recorded in 1825 in "The Port Folio", a Philadelphia literary journal, as a literary piece and later picked up by various newspapers. Although originally published anonymously, it was later revealed to be the work of James Hall, brother of "The Port Folio"s editor. There is no writing from Hugh Glass himself to corroborate the veracity of it. Also, it is likely to have been embellished over the years as a legend.


title: Hugh Glass

text: Glass was born in Pennsylvania, to Irish parents. His life before the famous bear attack is largely unverifiable, and his frontier story contained numerous embellishments. He was reported to have been captured by pirates under the command of Gulf of Mexico chief Jean Lafitte off the coast of Texas in 1816, and was forced to become a pirate for up to two years. Glass allegedly escaped by swimming to shore near what is present-day Galveston, Texas. He was later rumored to have been captured by the Pawnee tribe, with whom he lived for several years. Glass traveled to St. Louis, Missouri in 1821, accompanying several Pawnee delegates invited to meet with U.S. authorities.


title: Hugh Glass

text: In 1822, many men responded to an advertisement in the "Missouri Gazette and Public Advertiser" placed by General William Henry Ashley, which called for a corps of 100 men to "ascend the river Missouri" as part of a fur-trading venture. Many of them, who later earned reputations as famous mountain men, joined the enterprise, including James Beckwourth, David Jackson, William Sublette, Jim Bridger, Thomas Fitzpatrick, James Clyman and Jedediah Smith. These men and others would later be known as "Ashley's Hundred". Glass, however, did not join Ashley's company until the next year, when he ascended the Missouri River with Ashley. In June 1823 they met up with many of the men that had joined in 1822, and were attacked by Arikara warriors. Glass was apparently shot in the leg and the survivors retreated downstream and sent for help.


title: Hugh Glass

text: Glass and the rest of the Ashley Party eventually returned to Fort Kiowa to regroup for the trip west. Andrew Henry, Ashley's partner, had joined the group, and he along with Glass and several others set out overland to the Yellowstone River. Near the forks of the Grand River, near present-day Shadehill Reservoir, Perkins County, South Dakota, while scouting for game for the expedition larder, Glass surprised and disturbed a mother grizzly bear with two cubs. The bear charged, picked him up, bit, slashed and lacerated his flesh, severely wounded him, and forced him to the ground. Glass nevertheless managed to kill the bear with help from his trapping party, but was left badly mauled. The men were convinced Glass would not survive his injuries; nevertheless, they carried Glass on a litter for two days, but doing so greatly slowed the pace of the group's travel.