Abstract:
A fault tolerant method by which individual components of a server are monitored and controlled through independent, programmable microcontrollers interconnected through a microcontroller network. An external agent can control and monitor the microcontrollers by extending the interconnection network beyond the physical server. Intervention of the server operating system software is not required and is not utilized for the access and control operations. The method includes the processes running on a remote interface so as to enable communication between the microcontroller network and an external modem that communicates with a remote client machine. The remote interface also provides for connection to a local client machine.

Description:
RELATED APPLICATIONS 
     The subject matter of U.S. patent application entitled “System Architecture for Remote Access and Control of Environmental Management,” filed on Oct. 1, 1997, application Ser. No. 08/942,160, and is related to this application. 
     PRIORITY CLAIM 
     The benefit under 35 U.S.C. § 119(e) of the following U.S. provisional application(s) is hereby claimed: 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
               
               
                   
                 Application 
                 Filing 
               
               
                 Title 
                 No. 
                 Date 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 “Remote Access and Control of Environmental 
                 60/046,397 
                 May 13, 
               
               
                 Management System” 
                   
                 1997 
               
               
                 “hardware and Software Architecture for 
                 60/046,016 
                 May 13, 
               
               
                 Inter-Connecting an Environmental 
                   
                 1997 
               
               
                 Management System with a Remote Interface” 
               
               
                 “Self Management Protocol for a Fly-By-Wire 
                 60/046,416 
                 May 13, 
               
               
                 Sevice Processor” 
                   
                 1997 
               
               
                   
               
             
          
         
       
     
    
    
     APPENDICES 
     Appendix A, which forms a part of this disclosure, is a list of commonly owned copending U.S. patent applications. Each one of the applications listed in Appendix A is hereby incorporated herein in its entirety by reference thereto. 
     COPYRIGHT RIGHTS 
     A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to fault tolerant computer systems. More specifically, the invention is directed to a system for providing remote access and control of server environmental management. 
     2. Description of the Related Technology 
     As enterprise-class servers become more powerful and more capable, they are also becoming increasingly sophisticated and complex. For many companies, these changes lead to concerns over server reliability and manageability, particularly in light of the increasingly critical role of server-based applications. While in the past many systems administrators were comfortable with all of the various components that made up a standards-based network server, today&#39;s generation of servers can appear as an incomprehensible, unmanageable black box. Without visibility into the underlying behavior of the system, the administrator must “fly blind.” Too often the only indicators the network manager has on the relative health of a particular server is whether or not it is running. 
     It is well-acknowledged that there is a lack of reliability and availability of most standards-based servers. Server downtime, resulting either from hardware or software faults or from regular maintenance, continues to be a significant problem. By one estimate, the cost of downtime in mission critical environments has risen to an annual total of $4.0 billion for U.S. businesses, with the average downtime event resulting in a $140 thousand loss in the retail industry and a $450 thousand loss in the securities industry. It has been reported that companies lose as much as $250 thousand in employee productivity for every 1% of computer downtime. With emerging Internet, intranet and collaborative applications taking on more essential business roles every day, the cost of network server downtime will continue to spiral upward. 
     While hardware fault tolerance is an important element of an overall high availability architecture, it is only one piece of the puzzle. Studies show that a significant percentage of network server downtime is caused by transient faults in the I/O subsystem. These faults may be due, for example, to the device driver, the adapter card firmware, or hardware which does not properly handle concurrent errors, and often causes servers to crash or hang. The result is hours of downtime per failure, while a system administrator discovers the failure takes some action, and manually reboots the server. In many cases, data volumes on hard disk drives become corrupt and must be repaired when the volume is mounted. A dismount-and-mount cycle may result from the lack of “hot pluggability” in current standards-based servers. Diagnosing intermittent errors can be a frustrating and time-consuming process. For a system to deliver consistently high availability, it must be resilient to these types of faults. Accurate and available information about such faults is central to diagnosing the underlying problems and taking corrective action. 
     Modern fault tolerant systems have the functionality to provide the ambient temperature of a storage device enclosure and the operational status of other components such as the cooling fans and power supply. However, a limitation of these server systems is that they do not contain self-managing processes to correct malfunctions. Also, if a malfunction occurs in a typical server, it relies on the operating system software to report, record and manage recovery of the fault. However, many types of faults will prevent such software from carrying out these tasks. For example, a disk drive failure can prevent recording of the fault in a log file on that disk drive. If the system error caused the system to power down, then the system administrator would never know the source of the error. 
     Traditional systems are lacking in detail and sophistication when notifying system administrators of system malfunctions. System administrators are in need of a graphical user interface for monitoring the health of a network of servers. Administrators need a simple point-and-click interface to evaluate the health of each server in the network. In addition, existing fault tolerant servers rely upon operating system maintained logs for error recording. These systems are not capable of maintaining information when the operating system is inoperable due to a system malfunction. Existing systems do not have a system log for maintaining information when the main computational processors are inoperable. 
     Another limitation of the typical fault tolerant system is that the control logic for the diagnostic system is associated with a particular processor. Thus, if the environmental control processor malfunctioned, then all diagnostic activity on the computer would cease. In traditional systems, if a controller dedicated to the fan system failed, then all fan activity could cease resulting in overheating and ultimate failure of the server. What is desired is a way to obtain diagnostic information when the server OS is not operational or even when main power to the server is down. 
     Existing fault tolerant systems also lack the power to remotely control a particular server, such as powering up and down, resetting, retrieving or updating system status, displaying flight recorder and so forth. Such control of the server is desired even when the server power is down. For example, if the operating system on the remote machine failed, then a system administrator would have to physically go to the remote machine to re-boot the malfunctioning machine before any system information could be obtained or diagnostics could be started. 
     Therefore, a need exists for improvements in server management which will result in greater reliability and dependability of operation. Server users are in need of a management system by which the users can accurately gauge the health of their system. Users need a high availability system that must not only be resilient to faults, but must allow for maintenance, modification, and growth—without downtime. System users must be able to replace failed components, and add new functionality, such as new network interfaces, disk interface cards and storage, without impacting existing users. As system demands grow, organizations must frequently expand, or scale, their computing infrastructure, adding new processing power, memory, storage and I/O capacity. With demand for 24-hour access to critical, server-based information resources, planned system downtime for system service or expansion has become unacceptable. 
     SUMMARY OF THE INVENTION 
     Embodiments of the inventive remote access system provides system administrators with new levels of client/server system availability and management. It gives system administrators and network managers a comprehensive view into the underlying health of the server—in real time, whether on-site or off-site. In the event of a failure, the invention enables the administrator to learn why the system failed, why the system was unable to boot, and to control certain functions of the server from a remote station. 
     One embodiment of the present invention is a method of external management of a computer, the method comprising the acts of monitoring at least one environmental condition of at least one component of a first computer; and communicating the results of monitoring to a second computer, without an operating system executing on the first computer. 
     Another embodiment of the present invention is a method of external management of a computer environment, the method comprising the acts of providing a first computer; providing a second computer; selecting, at the second computer, a component of the first computer to be managed; selecting, at the second computer, a management operation to be performed by the first computer on the selected component; communicating the selected component and selected operation from the second computer to the first computer; and performing the selected operation on the selected component at the first computer. 
     Yet another embodiment of the present invention is a method of external management of a computer environment, the method comprising the acts of connecting a remote interface to a first computer and a second computer; providing a management command at the second computer directed to the first computer; encapsulating the command in a communications protocol; transmitting the encapsulated command to the remote interface; communicating the command received by the remote interface to the first computer; and performing the command on the first computer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top level block diagram of microcontroller network components utilized by an embodiment of the present invention. 
     FIG. 2 is a block diagram of the server portion of the microcontroller network shown in FIG.  1 . 
     FIG. 3 is a block diagram of a remote interface board (RIB) that is part of the microcontroller network shown in FIGS. 1 and 2. 
     FIG. 4 is a diagram of serial protocol message formats utilized by the RIB shown in FIG.  3 . 
     FIGS. 5 a  and  5   b  are a flowchart of a RIB microcontroller that is a part of the microcontroller network shown in FIGS. 1 and 2. 
     FIG. 6 is a diagram of a modem dialing and answering state machine defined in FIG. 5 a.   
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description presents a description of certain specific embodiments of the present invention. In this description, reference is made to the drawings wherein like parts are designated with like numerals throughout. 
     For convenience, the discussion of the invention is organized into the following principal sections: Introduction, Server System, Microcontroller Network, Remote Interface Board, Remote Interface Serial Protocol, and RIB Microcontroller Operation. 
     I. INTRODUCTION 
     The inventive computer server system and client computer includes a distributed hardware environment management system that is built as a small self-contained network of microcontrollers. Operating independently of the system processor and operating system software, embodiments of present invention uses separate processors for providing information and managing the hardware environment including fans, power supplies and temperature. 
     Initialization, modification and retrieval of system conditions are performed through utilization of a remote interface by issuing commands to the environmental processors. The system conditions may include system log size, presence of faults in the system log, serial number for each of the environmental processors, serial numbers for each power supply of the system, system identification, system log count, power settings and presence, canister presence, temperature, BUS/CORE speed ratio, fan speeds, settings for fan faults, LCD display, Non-Maskable Interrupt (NMI) request bits, CPU fault summary, FRU status, JTAG enable bit, system log information, remote access password, over-temperature fault, CPU error bits, CPU presence, CPU thermal fault bits, and remote port modem. The aforementioned list of capabilities provided by the present environmental system is not all-inclusive. 
     The server system and client computer provides mechanisms for the evaluation of the data that the system collects and methods for the diagnosis and repair of server problems in a manner that system errors can be effectively and efficiently managed. The time to evaluate and repair problems is minimized. The server system ensures that the system will not go down, so long as sufficient system resources are available to continue operation, but rather degrade gracefully until the faulty components can be replaced. 
     II. SERVER SYSTEM 
     Referring to FIG. 1, a server system  100  with a remote client computer will be described. In a one embodiment, the server system hardware environment  100  may be built around a self-contained network of microcontrollers, such as, for example, a remote interface microcontroller on the remote interface board or circuit  104 , a system interface microcontroller  106  and a system recorder microcontroller  110 . This distributed service processor network  102  may operate as a fully self-contained subsystem within the server system  100 , continuously monitoring and managing the physical environment of the machine (e.g., temperature, voltages, fan status). The microcontroller network  102  continues to operate and provides a system administrator with critical system information, regardless of the operational status of the server  100 . 
     Information collected and analyzed by the microcontroller network  102  can be presented to a system administrator using either SNMP-based system management software (not shown), or using microcontroller network Recovery Manager software  130  through a local connection  121  or a dial-in connection  123 . The system management software, which interfaces with the operating system (OS)  108  such as Microsoft Windows NT Version 4.0 or Novell Netware Version 4.11, for example, provides the ability to manage the specific characteristics of the server system, including Hot Plug Peripheral Component Interconnect (PCI), power and cooling status, as well as the ability to handle alerts associated with these features. 
     The microcontroller network Recovery Manager software  130  allows the system administrator to query the status of the server system  100  through the microcontroller network  102 , even when the server is down. Using the microcontroller network remote management capability, a system administrator can use the Recovery Manager  130  to re-start a failed system through a modem connection  123 . First, the administrator can remotely view the microcontroller network Flight Recorder, a feature that stores all system messages, status and error reports in a circular Non-Volatile Random Access Memory buffer (NVRAM)  112 . Then, after determining the cause of the system problem, the administrator can use microcontroller network “fly by wire” capability to reset the system, as well as to power the system off or on. “Fly by wire” denotes that no switch, indicator or other control is directly connected to the function it monitors or controls, but instead, all the control and monitoring connections are made by the microcontroller network  102 . 
     The remote interface board (RIB)  104  interfaces the server system  100  to an external client computer. The RIB  104  may be internal or external to an enclosure of the server  100 . Furthermore, the RIB may be incorporated onto another circuit of the server, such as a system board  150  (FIG. 2) or a backplane  152  of the server. The RIB  104  connects to either a local client computer  122  at the same location as the server  100  or to a remote client computer  124  through an optional switch  120 . The client computer  122 / 124  may in one embodiment run either Microsoft Windows 95 or Windows NT Workstation version 4.0 operating system (OS)  132 . 
     The client computer  122 / 124  could be another server, such as, for example, a backup server. The client computer  122 / 124  could also be a handheld computer such as, for example, a personal digital assistant (PDA). It is not necessary that Operating System software be running on the client computer  122 / 124 . For example, the client computer  122 / 124  could be hard-wired for specific tasks, or could have special purpose embedded software. 
     The processor and RAM requirements of the client computer  122 / 124  are such as necessary by the OS  132 . The serial port of the client computer  122 / 124  may utilize a type 16550A Universal Asynchronous Receiver Transmitter (UART). The switch  120  facilitates either the local connection  121  or the modem connection  123  at any one time, but allows both types of connections to be connected to the switch. In an another embodiment, either the local connection  121  or the modem connection  123  is connected directly to the RIB  104 . The local connection  121  utilizes a readily available null-modem serial cable to connect to the local client computer. The modem connection may utilize a Hayes-compatible server modem  126  and a Hayes-compatible client modem  128 . In one embodiment, a model V.34X 33.6K data/fax modem available from Zoom is utilized as the client modem and the server modem. In another embodiment, a Sportster 33.6K data/fax modem available from US Robotics is utilized as the client modem. 
     The steps of connecting the remote client computer  124  to the server  100  will now be briefly described. The remote interface  104  has a serial port connector  204  (FIG. 3) that directly connects with a counterpart serial port connector of the external server modem  126  without the use of a cable. If desired, a serial cable could be used to interconnect the remote interface  104  and the server modem  126 . The cable end of an AC to DC power adapter (not shown, for example a 120 Volt AC to 7.5 Volt DC, or a 220V, European or Japanese adapter) is then connected to the DC power connector J2 ( 220 , FIG. 3) of the remote interface, while the double-prong end is plugged into a 120 Volt AC wall outlet. One end of an RJ-45 parallel-wire data cable  103  is then plugged into an RJ-45 jack ( 226 , FIG. 3) on the remote interface  104 , while the other end is plugged into a RJ-45 Recovery Manager jack on the server  100 . The RJ-45 jack on the server then connects to the microcontroller network  102 . The server modem  126  is then connected to a communications network  127  using an appropriate connector. The communications network  127  may be a public switched telephone network, although other modem types and communication networks are envisioned. For example, if cable modems are used for the server modem  126  and client modem  128 , the communications network can be a cable television network. As another example, satellite modulator/demodulators can be used in conjunction with a satellite network. 
     In another embodiment, the server modem to client modem connection may be implemented by an Internet connection utilizing the well known TCP/IP protocol. Any of several Internet access devices, such as modems or network interface cards, may be utilized. Thus, the communications network  127  may utilize either circuit or packet switching. 
     At the remote client computer  124 , a serial cable (25-pin D-shell)  129  is used to interconnect the client modem  128  and the client computer  124 . The client modem  128  is then connected to the communications network  127  using an appropriate connector. Each modem is then plugged into an appropriate power source for the modem, such as an AC outlet. At this time, the Recovery Manager software  130  is loaded into the client computer  124 , if not already present, and activated. 
     The steps of connecting the local client computer  122  to the server  100  are similar, but modems are not necessary. The main difference is that the serial port connector of the remote interface  104  connects to a serial port of the local client computer  122  by the null-modem serial cable  121 . 
     III. MICROCONTROLLER NETWORK 
     In one embodiment, the invention is implemented by a network of microcontrollers  102  (FIG.  1 ). The microcontrollers may provide functionality for system control, diagnostic routines, self-maintenance control, and event logging processors. A further description of the microcontrollers and microcontroller network is provided in U.S. patent application Ser. No. 08/942,402, entitled “Diagnostic and Managing Distributed Processor System”. 
     Referring to FIG. 2, in one embodiment of the invention, the network of microcontrollers  102  includes ten processors. One of the purposes of the microcontroller network  102  is to transfer messages to the other components of the server system  100 . The processors may include: a System Interface controller  106 , a CPU A controller  166 , a CPU B controller  168 , a System Recorder  110 , a Chassis controller  170 , a Canister A controller  172 , a Canister B controller  174 , a Canister C controller  176 , a Canister D controller  178  and a Remote Interface controller  200 . The Remote Interface controller  200  is located on the RIB  104  (FIG. 1) which is part of the server system  100 , but may preferably be external to the server enclosure. The System Interface controller  106 , the CPU A controller  166  and the CPU B controller  168  are located on thr system board  150  in the server  100 . Also located on the system board are one or more central processing units (CPUs) or microprocessors  164  and an Industry Standard Architecture (ISA) bus  162  that connects to the System Interface Controller  106 . Of course, other buses such as PCI, EISA and Microchannel may be used. The CPU  164  may be any conventional general purpose single-chip or multi-chip microprocessor such as a Pentium®, Pentium® Pro or Pentium® II processor available from Intel Corporation, a SPARC processor available from Sun Microsystems, a MIPS® processor available from Silicon Graphics, Inc., a Power PC® processor available from Motorola, or an ALPHA® processor available from Digital Equipment Corporation. In addition, the CPU  164  may be any conventional special purpose microprocessor such as a digital signal processor or a graphics processor. 
     The System Recorder  110  and Chassis controller  170 , along with the NVRAM  112  that connects to the System Recorder  110 , may be located on the backplane  152  of the server  100 . The System Recorder  110  and Chassis controller  170  are typically the first microcontrollers to power up when server power is applied. The System Recorder  110 , the Chassis controller  170  and the Remote Interface microcontroller  200  are the three microcontrollers that have a bias 5 volt power supplied to them. If main server power is off, an independent power supply source for the bias 5 volt power is provided by the RIB  104  (FIG.  1 ). The Canister controllers  172 - 178  are not considered to be part of the backplane  152  because they are located on separate cards and are removable. 
     Each of the microcontrollers has a unique system identifier or address. The addresses are as follows in Table 1: 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Microcontroller 
                 Address 
               
               
                   
                   
               
             
             
               
                   
                 System Interface controller 106 
                 10 
               
               
                   
                 CPU A controller 166 
                 03 
               
               
                   
                 CPU B controller 168 
                 04 
               
               
                   
                 System Recorder 110 
                 01 
               
               
                   
                 Chassis controller 170 
                 02 
               
               
                   
                 Canister A controller 172 
                 20 
               
               
                   
                 Canister B controller 174 
                 21 
               
               
                   
                 Canister C controller 176 
                 22 
               
               
                   
                 Canister D controller 178 
                 23 
               
               
                   
                 Remote Interface controller 200 
                 11 
               
               
                   
                   
               
             
          
         
       
     
     The microcontrollers may be Microchip Technologies, Inc. PIC processors in one embodiment, although other microcontrollers, such as an 8051 available from Intel, an 8751 available from Atmel, and a P80CL580 microprocessor available from Philips, could be utilized. The PIC16C74 (Chassis controller  170 ) and PIC16C65 (the other controllers) are members of the PIC16CXX family of CMOS, fully-static, EPROM-based 8-bit microcontrollers. The PIC controllers have 192 bytes of RAM, in addition to program memory, three timer/counters, two capture/compare/Pulse Width Modulation modules and two serial ports. The synchronous serial port is configured as a two-wire Inter-Integrated Circuit (I 2 C) bus in one embodiment of the invention. The PIC controllers use a Harvard architecture in which program and data are accessed from separate memories. This improves bandwidth over traditional von Neumann architecture processors where program and data are fetched from the same memory. Separating program and data memory further allows instructions to be sized differently than the 8-bit wide data word. Instruction opcodes are 14-bit wide making it possible to have all single word instructions. A 14-bit wide program memory access bus fetches a 14-bit instruction in a single cycle. 
     In one embodiment of the invention, the microcontrollers communicate through an I 2 C serial bus, also referred to as a microcontroller bus  160 . The document “The I 2 C Bus and How to Use It” (Philips Semiconductor, 1992) is hereby incorporated by reference. The I 2 C bus is a bidirectional two-wire bus that may operate at a 400 kbps. However, other bus structures and protocols could be employed in connection with this invention. For example, Apple Computer ADB, Universal Serial Bus, IEEE-1394 (Firewire), IEEE-488 (GPIB), RS-485, or Controller Area Network (CAN) could be utilized as the microcontroller bus. Control on the microcontroller bus is distributed. Each microcontroller can be a sender (a master) or a receiver (a slave) and each is interconnected by this bus. A microcontroller directly controls its own resources, and indirectly controls resources of other microcontrollers on the bus. 
     Here are some of the features of the I 2 C-bus: 
     Two bus lines are utilized: a serial data line (SDA) and a serial clock line (SCL). 
     Each device connected to the bus is software addressable by a unique address and simple master/slave relationships exist at all times; masters can operate as master-transmitters or as master-receivers. 
     The bus is a true multi-master bus including collision detection and arbitration to prevent data corruption if two or more masters simultaneously initiate data transfer. 
     Serial, 8-bit oriented, bidirectional data transfers can be made at up to 400 kbit/second in the fast mode. 
     Two wires, serial data (SDA) and serial clock (SCL), carry information between the devices connected to the I 2 C bus. Each device is recognized by a unique address and can operate as either a transmitter or receiver, depending on the function of the device. For example, a memory device connected to the I 2 C bus could both receive and transmit data. In addition to transmitters and receivers, devices can also be considered as masters or slaves when performing data transfers (see Table 2). A master is the device which initiates a data transfer on the bus and generates the clock signals to permit that transfer. At that time, any device addressed is considered a slave. 
     
       
         
               
             
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Definition of I 2 C-bus terminology 
               
             
          
           
               
                 Term 
                 Description 
               
               
                   
               
               
                 Transmitter 
                 The device which sends the data to the bus 
               
               
                 Receiver 
                 The device which receives the data from the bus 
               
               
                 Master 
                 The device which initiates a transfer, generates clock 
               
               
                   
                 signals and terminates a transfer 
               
               
                 Slave 
                 The device addressed by a master 
               
               
                 Multi-master 
                 More than one master can attempt to control the bus at 
               
               
                   
                 the same time without corrupting the message 
               
               
                 Arbitration 
                 Procedure to ensure that, if more than one master 
               
               
                   
                 simultaneously tries to control the bus, only one is 
               
               
                   
                 allowed to do so and the message is not corrupted 
               
               
                 Synchronization 
                 Procedure to synchronize the clock signal of two or 
               
               
                   
                 more devices 
               
               
                   
               
             
          
         
       
     
     The I 2 C-bus is a multi-master bus. This means that more than one device capable of controlling the bus can be connected to it. As masters are usually microcontrollers, consider the case of a data transfer between two microcontrollers connected to the I 2 C-bus. This highlights the master-slave and receiver-transmitter relationships to be found on the I 2 C-bus. It should be noted that these relationships are not permanent, but depend on the direction of data transfer at that time. The transfer of data would proceed as follows: 
     1) Suppose microcontroller A wants to send information to microcontroller B: 
     microcontroller A (master), addresses microcontroller B (slave); 
     microcontroller A (master-transmitter), sends data to microcontroller B (slave-receiver); 
     microcontroller A terminates the transfer. 
     2) If microcontroller A wants to receive information from microcontroller B: 
     microcontroller A (master addresses microcontroller B (slave); 
     microcontroller A (master-receiver) receives data from microcontroller B (slave-transmitter); 
     microcontroller A terminates the transfer. 
     Even in this situation, the master (microcontroller A) generates the timing and terminates the transfer. 
     The possibility of connecting more than one microcontroller to the I 2 C-bus means that more than one master could try to initiate a data transfer at the same time. To avoid the chaos that might ensue from such an event, an arbitration procedure has been developed. This procedure relies on the wired-AND connection of all I 2 C interfaces to the I 2 C-bus. 
     If two or more masters try to put information onto the bus, the first to produce a ‘one’ when the other produces a ‘zero’ will lose the arbitration. The clock signals during arbitration are a synchronized combination of the clocks generated by the masters using the wired-AND connection to the SCL line. 
     Generation of clock signal on the I 2 C-bus is the responsibility of master devices. Each master microcontroller generates its own clock signals when transferring data on the bus. 
     The command, diagnostic, monitoring and history functions of the microcontroller network  102  are accessed using a global network memory model in one embodiment. That is, any function may be queried simply by generating a network “read” request targeted at the fuiction&#39;s known global network address. In the same fashion, a function may be exercised simply by “writing” to its global network address. Any microcontroller may initiate read/write activity by sending a message on the I 2 C bus to the microcontroller responsible for the function (which can be determined from the known global address of the function). The network memory model includes typing information as part of the memory addressing information. 
     Using a network global memory model in one embodiment places relatively modest requirements for the I 2 C message protocol. 
     All messages conform to the I 2 C message format including addressing and read/write indication. 
     All I 2 C messages use seven bit addressing. 
     Any controller can originate (be a Master) or respond (be a Slave). 
     All message transactions consist of I 2 C “Combined format” messages. This is made up of two back-to-back I 2 C simple messages with a repeated START condition between (which does not allow for re-arbitrating the bus). The first message is a Write (Master to Slave) and the second message is a Read (Slave to Master). 
     Two types of transactions are used: Memory-Read and Memory-Write. 
     Sub-Addressing formats vary depending on data type being used. 
     IV. REMOTE INTERFACE BOARD 
     Referring to FIG. 3, the remote interface board (RIB)  104 , previously shown in FIG. 1, will now be described. The RIB is an interface between the microcontroller network  102  (FIG. 1) of the server system  100  and an external client computer  122 / 124 . The server system status and commands are passed through the RS232 connector port  204  at the client side of the RIB to the microcontroller network  102  on the server  100 , controlled through the on-board PIC16C65 microcontroller  200 . Signals in the microcontroller network  102  are transported by the microcontroller bus  160  (FIG.  2 ). In one embodiment, the microcontroller bus  160  utilizes the I 2 C bus protocol, previously described. The signals on the microcontroller bus  160  are received from the server  100  by the RIB  104  on the RJ-45 cable  103  and are translated by the PIC16C65 microcontroller  200  into an eight signal RS232 protocol. These RS232 signals are passed through a RS232 line transceiver  202 , such as a LT1133A chip available from Linear Technology, with a baud rate capable of reaching the speed of 120 kbaud. A 25 pin D-Sub connector  204  connects to the other side of the line transceiver  202  and provides the point at which either the local client computer  122  or the server modem  126  makes a connection. 
     The two wire microcontroller bus  160  is brought in from the server  100  and passed to the microcontroller  200  using the RJ-45 cable  103  and RJ-45 connector  226 . A switch  228 , such as a QS3126 switch available from Quick Logic, connects to the RJ-45 connector  226  and provides isolation for the data and clock bus signals internal and external to the RIB  104 . If the RIB  104  and switch  228  have power, the switch  228  feeds the bus signals through to a microcontroller bus extender  230 . Otherwise, if the switch  228  does not have power, the microcontroller bus  160  is isolated from the RIB  104 . The bus extender  230  connects between the switch  228  and the microcontroller  200 . The bus extender  230  is a buffer providing drive capability for the clock and data signals. In one embodiment, the bus extender  230  is a 82B715 chip available from Philips Semiconductor. Microcontroller  200  Port C, bit  3  is the clocking bit and Port C, bit  4  is the data line. 
     Communication with the server modem  126  is based on the RS 232  protocol. The microcontroller  200  generates the receive and the transmit signals, where the signal levels are transposed to the RS232 levels by the LT1133A line transceiver  202 . There are three transmit signals, RTS, SOUT and DTR, which are from Port A, bits  2 ,  3  and  4  of the microcontroller  200 , whereas the five receive signals are from two ports, DCD, DSR from Port C, bits  1  and  0  and SIN, CTS and RI from Port A, bits  5 ,  0  and  1 . 
     In one embodiment, the 25 pin RS232 pin connector  204  is used instead a 9 pin connector, since this type of connector is more common. All the extra pins are not connected except the pins  1  and  7 , where pin  1  is chassis ground and pin  7  is a signal ground. 
     A static random access memory (SRAM)  208  connects to the microcontroller  200 . In one embodiment, the SRAM  208  is a 32k×8 MT5LC2568 that is available from Micron Technology. The SRAM  208  is also available from other memory manufacturers. An external address register  206 , such as an ABT374, available from Texas Instruments is used for latching the higher addressing bits (A 8 -A 14 ) of the address for the SRAM  208  so as to expand the address to fifteen bits. The SRAM  208  is used to store system status data, system log data from the NVRAM  112  (FIG.  1 ), and other message data for transfer to the external interface port  204  or to a microcontroller on the microcontroller bus  160  (FIG.  2 ). 
     Port D of the microcontroller  200  is the address port. Port B is the data bus for the bidirectional data interconnect. Port E is for the SRAM enable, output tristate and write control signals. The microcontroller  200  operates at a frequency of 12 MHz. 
     An Erasable Programmable Read Only Memory (EPROM)  212  is used for storing board serial number identification information for the RIB  104 . The serial number memory  212  is signal powered, retaining the charge into a capacitor sourced through the data line. In one embodiment, the serial number memory  212  stores eight sixteen-byte serial/revision numbers (for maintaining the rework/revision history) and is a DS2502 chip available from Dallas Semiconductor. The programming of memory  212  is handled using a jumper applied through an external connector J1  210 . The serial number memory  212  connects to the microcontroller  200  at Port C, bit  6  and to the external connector J1  210 . 
     The RIB  104  may be powered through a 7.5 Volt/800 mA supply unit that plugs into a connector J2  220 . In one embodiment, the supply unit is 120 Volt AC to DC wall adapter. Connector J2  220  feeds a LT1376 high frequency switching regulator  222 , available from Linear Technology, which regulates the power source. The regulated power output is used locally by the components on the RIB  104 , and 300 mA are sourced to the microcontroller network  102  through a 300 mA fuse  224  and the RJ-45 connector  226 . Thus, the output of the regulator  222  provides an alternative source for a bias-powered partition of the microcontroller network  102 . The bias-powered partition includes the system recorder  110  (FIG.  1 ), the NVRAM  112  and the Chassis controller  170  (FIG. 2) which are resident on the server backplane  152 . 
     V. REMOTE INTERFACE SERIAL PROTOCOL 
     The microcontroller network remote interface serial protocol communicates microcontroller network messages across a point-to-point serial link. This link is between the RIB controller  200  that is in communication with the Recovery Manager  130  at the remote client  122 / 124 . This protocol encapsulates microcontroller network messages in a transmission packet to provide error-free communication and link security. 
     In one embodiment, the remote interface serial protocol uses the concept of byte stuffing. This means that certain byte values in the data stream have a particular meaning. If that byte value is transmitted by the underlying application as data, it must be transmitted as a two-byte sequence. 
     The bytes that have a special meaning in this protocol are: 
     
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 SOM 306 
                 Start of a message 
               
               
                   
                 EOM 316 
                 End of a message 
               
               
                   
                 SUB 
                 The next byte in the data stream must be 
               
               
                   
                   
                 substituted before processing. 
               
               
                   
                 INT 320 
                 Event Interrupt 
               
               
                   
                 Data 312 
                 An entire microcontroller network message 
               
               
                   
                   
               
             
          
         
       
     
     As stated above, if any of these byte values occur as data in a message, a two-byte sequence must be substituted for that byte. The sequence is a byte with the value of SUB, followed by a type with the value of the original byte, which is incremented by one. For example, if a SUB byte occurs in a message, it is transmitted as a SUB followed by a byte that has a value of SUB+1. 
     Referring to FIG. 4, the two types of messages  300  used by the remote interface serial protocol will be described. 
     1. Requests  302 , which are sent by remote management (client) computers  122 / 124  (FIG. 1) to the remote interface  104 . 
     2. Responses  304 , which are returned to the requester  122 / 124  by the remote interface  104 . 
     The fields of the messages are defined as follows: 
     
       
         
               
               
             
           
               
                   
               
             
             
               
                 SOM 306 
                 A special data byte value marking the start of a 
               
               
                   
                 message. 
               
               
                 EOM 316 
                 A special data byte value marking the end of a 
               
               
                   
                 message. 
               
               
                 Seq. #308 
                 A one-byte sequence number, which is incremented 
               
               
                   
                 on each request. It is stored in the response. 
               
               
                 TYPE 310 
                 One of the following types of requests: 
               
               
                   IDENTIFY 
                 Requests the remote interface to send back identi- 
               
               
                   
                 fication information about the system to which it is 
               
               
                   
                 connected. It also resets the next expected sequence 
               
               
                   
                 number. Security authorization does not need to be 
               
               
                   
                 established before the request is issued. 
               
               
                   SECURE 
                 Establishes secure authorization on the serial link by 
               
               
                   
                 checking password security data provided in the 
               
               
                   
                 message with the microcontroller network password. 
               
               
                   UNSECURE 
                 Clears security authorization on the link and 
               
               
                   
                 attempts to disconnect it. This requires security 
               
               
                   
                 authorization to have been previously established. 
               
               
                   MESSAGE 
                 Passes the data portions of the message to the 
               
               
                   
                 microcontroller network for execution. The response 
               
               
                   
                 from the microcontroller network is sent back in the 
               
               
                   
                 data portion of the response. This requires security 
               
               
                   
                 authorization to have been previously established. 
               
               
                   POLL 
                 Queries the status of the remote interface. This 
               
               
                   
                 request is generally used to determine if an event is 
               
               
                   
                 pending in the remote interface. 
               
               
                 STATUS 318 
                 One of the following response status values: 
               
               
                   OK 
                 Everything relating to communication with the 
               
               
                   
                 remote interface is successful. 
               
               
                   OK_EVENT 
                 Everything relating to communication with the 
               
               
                   
                 remote interface is successful. In addition, there is 
               
               
                   
                 one or more events pending in the remote interface. 
               
               
                   SEQUENCE 
                 The sequence number of the request is neither the 
               
               
                   
                 current sequence number or retransmission request, 
               
               
                   
                 nor the next expected sequence number or new re- 
               
               
                   
                 quest. Sequence numbers may be reset by an 
               
               
                   
                 IDENTIFY request. 
               
               
                   CHECK 
                 The check byte in the request message is received 
               
               
                   
                 incorrectly. 
               
               
                   FORMAT 
                 Something about the format of the message is 
               
               
                   
                 incorrect. Most likely, the type field contains an 
               
               
                   
                 invalid value. 
               
               
                   SECURE 
                 The message requires that security authorization be 
               
               
                   
                 in effect, or, if the message has a TYPE value of 
               
               
                   
                 SECURE, the security check failed. 
               
               
                 Check 314 
                 Indicates a message integrity check byte. Currently 
               
               
                   
                 the value is 256 minus the sum of previous bytes in 
               
               
                   
                 the message. For example, adding all bytes in the 
               
               
                   
                 message up to and including the check byte should 
               
               
                   
                 produce a result of zero (0). 
               
               
                 INT 320 
                 A special one-byte message sent by the remote 
               
               
                   
                 interface when it detects the transition from no 
               
               
                   
                 events pending to one or more events pending. This 
               
               
                   
                 message can be used to trigger reading events from 
               
               
                   
                 the remote interface. Events should be read until the 
               
               
                   
                 return status changes form OK_EVENT to OK. 
               
               
                   
               
             
          
         
       
     
     VI. RIB MICROCONTROLLER OPERATION 
     The remote interface is the bridge to link the microcontroller bus to the outside world via a RS232 serial port through which a client computer can be connected. A message from the remote client side via RS232 usually starts with the “Identify” command which identifies the system name. See the message format associated with FIG. 4, above. The “Identify” command should be followed by the “Security” command with a password that is checked against the password stored in the NVRAM  112  (FIG.  1 ). If the passwords match, the remote RS232 link is put in “secure mode” and the remote interface  104  (FIG. 1) will now pass any “message” commands on to the microcontroller network bus  160  (FIG.  2 ). Before the remote application program disconnects the link, it should send the “Unsecure” command to take the RS232 link out of “secure mode”. 
     Referring to FIGS. 5 a  and  5   b,  embodiments of the RIB microcontroller process  400  will be described. The process  400  is implemented as a computer program, termed firmware, written in PIC assembly language. The assembled machine code is stored in the microcontroller EPROM where each instruction is fetched for execution by the processor. The EPROM provides 4K×14 program memory space, all on-chip. Program execution is using the internal memory. Of course, any of a variety of general purpose and special purpose processors could be used and the programming of the process  400  could be in high level code such as C or Java. 
     Beginning at an initialize PIC state  402 , process  400  initializes the variables, stack pointer, and other structures of the RIB microcontroller  200  (FIG.  3 ). Moving to state  404 , a return point called “main” is identified in process  400 . Proceeding to a decision state  406 , process  400  determines if the RS232 port is transmitting data. If so, process  400  moves to state  408  to send a character (one byte) if there is data in the SRAM  208  to be sent out on the RS232 port  204 . A process of receiving data via the RS232 port  204  is not shown herein. Receiving data via the port  204  is initiated by the use of an interrupt. 
     At the completion of state  408 , or if decision state  406  evaluates to a false condition, process  400  proceeds to a Check Modem Status function  410  that is implemented as a modem dialing and answering state machine. Function  410  checks the status of the modem  126  for any possible activity. Function  410  will be further described in conjunction with FIG.  6 . Advancing to a decision state  412 , process  400  determines if any server event is pending. Event types include, for example, CPU status change, power status change, canister status change, fan status change, temperature, and operating system timeout. If an event is pending, process  400  proceeds to state  414  and sends an event message to the client computer  122 / 124  via the RS232 port. If no event is pending, as determined at decision state  412 , process  400  continues at a decision state  416 . At decision state  416 , process  400  checks to see if a RS232 remote message has been received from the client computer  122 / 124 . If not, process  400  moves back to the “main” loop  404 , as described above. One reason that a message has not been received yet is that the modem is not yet transmitting. 
     If a message has been received, as determined at decision state  416 , process moves to the appropriate state  420 - 426  to handle one of four command types: Identify, Secure, Unsecure, and Message. At state  420 , process  400  performs the Identify command and identifies the system by responding with the system name retrieved from the System Recorder memory  112  (FIG.  1 ). 
     At state  422 , process  400  performs the Secure command and gets the password with the command and checks it against the password from the NVRAM  112  (FIG.  1 ). If the passwords match, the access right is granted (opens secure mode), otherwise, reject the intent. 
     At state  424 , process  400  performs the Unsecure command and releases the remote access right, i.e., closes secure mode. At the completion of states  420 ,  422  or  424 , process  400  proceeds through off-page connector E  430  to state  438  (FIG. 5 b ). 
     At state  426  on FIG. 5 b  (through off-page connector D  418 ), process  400  performs the Message command and gets remote message data from the RIB SRAM  208  (FIG.  3 ). Proceeding to a decision state  432 , process  400  determines if this message command is for the remote interface  104 . If it is, process  400  executes the internal remote interface function command, such as a Read Revision of the RIB command. If the message command is not for the remote interface, as determined by decision state  432 , process  400  moves to state  436  and passes the message command to its destination (external to the remote interface) via the microcontroller bus. This facilitates communication with another microcontroller for a command to read or write information, for example. 
     At the completion of states  420 ,  422 ,  424 ,  434  or  436 , process  400  advances to state  438  and stores the response data for the command into the SRAM  208  (FIG. 3) to be sent back to the client computer  122 / 124 . Moving to state  440 , process  400  transmit the first byte of data back on the RS 232  port  204  to the client computer  122 / 124 . After the byte of data has been transmitted at state  440 , process  400  moves back to the “main” loop  404  (on FIG. 5 a ), as described above. Referring to FIG. 6, embodiments of the Check Modem Status function  410  will now be described. Function  410  is implemented as a modem dialing and answering state machine. Several terms useful for understanding of the modem dialing and answering state machine are listed in Table 3 below. 
     
       
         
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                 Modem Term 
                 Meaning 
               
               
                   
               
             
             
               
                 CTS 
                 clear to send 
               
               
                 DCD 
                 data carrier detect 
               
               
                 DSR 
                 data set ready 
               
               
                 DTR 
                 data transfer ready 
               
               
                 RTS 
                 request to send 
               
               
                 EOS 
                 end of string 
               
               
                 Protocol 
                 indicates whether RS232 serial data uses the messag- 
               
               
                   
                 ing protocol or whether the data is a string of bytes 
               
               
                 Ring 
                 modem is detecting an incoming ring signal from 
               
               
                   
                 another modem 
               
               
                 Local 
                 a connection to a local client computer (no modem 
               
               
                   
                 used) 
               
               
                 Modem Mode 
                 modem to modem connection 
               
               
                 Modem Already 
                 modem initialization string has already been sent and 
               
               
                 Set 
                 completed 
               
               
                   
               
             
          
         
       
     
     State machine  410  includes nine states, states  470 - 486 . State  470  denotes that the modem is disconnected, DTR and RTS are clear and the protocol is clear. Protocol is clear indicates that no message protocol processing is to occur for bytes on the RS232 link (because it would affect transmitting and receiving of modem control string bytes). The state machine  410  remains at the Modem Disconnect state  470  while CTS is clear OR there have been “n” dialing retries already OR there is no Ring OR DSR is clear. If DSR is set (active), the state machine  410  proceeds to a Local Modem state  486 , wherein RTS and DTR are set. The state machine  410  remains at state  486  while DSR is set. Is DSR clears or if Local AND Modem Mode are both set, the state machine  410  returns to Modem Disconnect state  470 . 
     The state machine  410  proceeds to Modem Soft Reset state  472  if a Call Out condition OR a Setup condition is achieved. Call Out is achieved if Modem Mode is set AND Modem Already Set is set AND CTS is set AND there have not been “n” dialing retries already. Setup is achieved if Modem Mode is set AND Modem Already Set is clear AND CTS is set. At Modem Soft Reset state  472 , DTR is set and RTS is set. The state machine  410  remains at state  472  while Send String Done is clear, i.e., the modem command string is still being sent to the modem. 
     The state machine  410  proceeds to Modem Test state  474  when Send String Done is set. The state machine  410  remains at state  474  while Send String Done is clear. The state machine  410  proceeds to Modem Result Code state  476  when Send String Done is set. The state machine  410  remains at state  476  while Modem Result Status Done is clear, i.e., the results status of the modem test at state  474  is not yet available. 
     The state machine  410  returns to Modem Disconnect state  470  from state  476  if Results Status OK is clear, i.e., the results status is not OK. However, if Results Status OK is set, i.e., the results status is correct, the state machine  410  proceeds to a Modem Setup state  478 , wherein Modem Already Set is set. The state machine  410  returns to Modem Disconnect state  470  from state  478  if there have been “n” dialing retries already. However, if there have not been “n” dialing retries already, the state machine  410  proceeds to a Modem Dialing state  480 , wherein the modem is dialed. 
     The state machine  410  remains at state  480  while the previous EOS has not been reached AND two seconds have not passed. The state machine  410  returns to Modem Disconnect state  470  from state  480  if Dial OK is clear, i.e., dialing the modem was not successful. However, if Dial OK is set, i.e., dialing the modem was successful, the state machine  410  proceeds to a Modem Answering state  482 . Another path to the Modem Answering state  482  is from the Modem Disconnect state  470  when a Ringing mode is achieved. Ringing mode is achieved if Modem Mode is set AND Modem Already Set is set AND CTS is set AND Ring is set. The state machine  410  remains at state  482  while DSR is clear OR DCD is clear. The state machine  410  returns to Modem Disconnect State  470  from state  482  if DCD is clear and a timeout occurs, i.e., no DCD is set within a timeout period (nobody answers). The state machine  410  proceeds to Remote Modem state  484  when DSR is set AND DCD is set. The modem transfers message data while at this state. When DCD clears, the state machine  410  returns to Modem Disconnect state  470  from state  484  or otherwise remains at state  484 . 
     While the above detailed description has shown, described, and pointed out the fundamental novel features of the invention as applied to various embodiments, it will be understood that various omissions and substitutions and changes in the form and details of the system illustrated may be made by those skilled in the art, without departing from the intent of the invention. 
     Appendix A 
     Incorporation by Reference of Commonly Owned Applications 
     The following patent applications, commonly owned and filed Oct. 1, 1997, are hereby incorporated herein in their entirety by reference thereto: 
     
       
         
               
               
               
             
           
               
                   
               
               
                   
                 application 
                 Attorney Docket 
               
               
                 Title 
                 Ser. No. 
                 No. 
               
               
                   
               
             
             
               
                 “System Architecture for Remote 
                 08/942,160 
                 MNFRAME.002A1 
               
               
                 Access and Control of 
               
               
                 Environmental Management” 
               
               
                 “System for Independent Powering 
                 08/942,410 
                 MNFRAME.002A3 
               
               
                 of Diagnostic Processes on a  
               
               
                 Computer System” 
               
               
                 “Method of Independent Powering 
                 08/942,320 
                 MNFRAME.002A4 
               
               
                 of Diagnostic Processes on a 
               
               
                 Computer System” 
               
               
                 “Diagnostic and Managing 
                 08/942,402 
                 MNFRAME.005A1 
               
               
                 Distributed Processor System” 
               
               
                 “Method for Managing a 
                 08/942,448 
                 MNFRAME.005A2 
               
               
                 Distributed Processor System” 
               
               
                 “System for Mapping En- 
                 08/942,222 
                 MNFRAME.005A3 
               
               
                 vironmental Resources to Memory 
               
               
                 for Program Access” 
               
               
                 “Method for Mapping Environ- 
                 08/942,214 
                 MNFRAME.005A4 
               
               
                 mental Resources to Memory for 
               
               
                 Program Access” 
               
               
                 “Hot Add of Devices Software 
                 08/942,309 
                 MNFRAME.006A1 
               
               
                 Architecture” 
               
               
                 “Method for The Hot Add 
                 08/942,306 
                 MNFRAME.006A2 
               
               
                 of Devices” 
               
               
                 “Hot Swap of Devices Software 
                 08/942,311 
                 MNFRAME.006A3 
               
               
                 Architecture” 
               
               
                 “Method for The Hot Swap 
                 08/942,457 
                 MNFRAME.006A4 
               
               
                 of Devices” 
               
               
                 “Method for the Hot Add of 
                 08/943,072 
                 MNFRAME.006A5 
               
               
                 a Network Adapter on a System 
               
               
                 Including a Dynamically Loaded 
               
               
                 Adapter Driver” 
               
               
                 “Method for the Hot Add of a 
                 08/942,069 
                 MNFRAME.006A6 
               
               
                 Mass Storage Adapter on a System 
               
               
                 Including a Statically Loaded 
               
               
                 Adapter Driver” 
               
               
                 “Method for the Hot Add of 
                 08/942,465 
                 MNFRAME.006A7 
               
               
                 a Network Adapter on a System 
               
               
                 Including a Statically Loaded 
               
               
                 Adapter Driver” 
               
               
                 “Method for the Hot Add of 
                 08/962,963 
                 MNFRAME.006A8 
               
               
                 a Mass Storage Adapter on a 
               
               
                 System Including a Dynamically 
               
               
                 Loaded Adapter Driver” 
               
               
                 “Method for the Hot Swap of 
                 08/943,078 
                 MNFRAME.006A9 
               
               
                 a Network Adapter on a System 
               
               
                 Including a Dynamically Loaded 
               
               
                 Adapter Driver” 
               
               
                 “Method for the Hot Swap of a 
                 08/942,336 
                 MNFRAME.006A10 
               
               
                 Mass Storage Adapter on a System 
               
               
                 Including a Statically Loaded 
               
               
                 Adapter Driver” 
               
               
                 “Method for the Hot Swap of a 
                 08/942,459 
                 MNFRAME.006A11 
               
               
                 Network Adapter on a System 
               
               
                 Including a Statically Loaded 
               
               
                 Adapter Driver” 
               
               
                 “Method for the Hot Swap of 
                 08/942,458 
                 MNFRAME.006A12 
               
               
                 a Mass Storage Adapter on a 
               
               
                 System Including a Dynamically 
               
               
                 Loaded Adapter Driver” 
               
               
                 “Method of Performing an 
                 08/942,463 
                 MNFRAME.008A 
               
               
                 Extensive Diagnostic Test in 
               
               
                 Conjunction with a BIOS Test 
               
               
                 Routine” 
               
               
                 “Apparatus for Performing an 
                 08/942,163 
                 MNFRAME.009A 
               
               
                 Extensive Diagnostic Test in 
               
               
                 Conjunction with a BIOS Test 
               
               
                 Routine” 
               
               
                 “Configuration Management 
                 08/941,268 
                 MNFRAME.010A 
               
               
                 Method for Hot Adding and Hot 
               
               
                 Replacing Devices” 
               
               
                 “Configuration Management 
                 08/942,408 
                 MNFRAME.011A 
               
               
                 System for Hot Adding and Hot 
               
               
                 Replacing Devices” 
               
               
                 “Apparatus for Interfacing 
                 08/942,382 
                 MNFRAME.012A 
               
               
                 Buses” 
               
               
                 “Method for Interfacing Buses” 
                 08/942,413 
                 MNFRAME.013A 
               
               
                 “Computer Fan Speed Control 
                 08/942,447 
                 MNFRAME.016A 
               
               
                 Device” 
               
               
                 “Computer Fan Speed Control 
                 08/942,216 
                 MNFRAME.017A 
               
               
                 Method” 
               
               
                 “System for Powering Up and 
                 08/943,076 
                 MNFRAME.018A 
               
               
                 Powering Down a Server” 
               
               
                 “Method of Powering Up and 
                 08/943,077 
                 MNFRAME.019A 
               
               
                 Powering Down a Server” 
               
               
                 “System for Resetting a Server” 
                 08/942,333 
                 MNFRAME.020A 
               
               
                 “Method of Resetting a Server” 
                 08/942,405 
                 MNFRAME.021A 
               
               
                 “System for Displaying Flight 
                 08/942,070 
                 MNFRAME.022A 
               
               
                 Recorder” 
               
               
                 “Method of Displaying Flight 
                 08/942,068 
                 MNFRAME.023A 
               
               
                 Recorder” 
               
               
                 “Synchronous Communication 
                 08/943,355 
                 MNFRAME.024A 
               
               
                 Interface” 
               
               
                 “Synchronous Communication 
                 08/942,004 
                 MNFRAME.025A 
               
               
                 Emulation” 
               
               
                 “Software System Facilitating the 
                 08/942,317 
                 MNFRAME.026A 
               
               
                 Replacement or Insertion of 
               
               
                 Devices in a Computer System” 
               
               
                 “Method for Facilitating the 
                 08/942,316 
                 MNFRAME.027A 
               
               
                 Replacement or Insertion of 
               
               
                 Devices in a Computer System” 
               
               
                 “System Management Graphical 
                 08/943,357 
                 MNFRAME.028A 
               
               
                 User Interface” 
               
               
                 “Display of System Information” 
                 08/942,195 
                 MNFRAME.029A 
               
               
                 “Data Management System 
                 08/942,129 
                 MNFRAME.030A 
               
               
                 Supporting Hot Plug Operations on 
               
               
                 a Computer” 
               
               
                 “Data Management Method 
                 08/942,124 
                 MNFRAME.031A 
               
               
                 Supporting Hot Plug Operations on 
               
               
                 a Computer” 
               
               
                 “Alert Configurator and Manager” 
                 08/942,005 
                 MNFRAME.032A 
               
               
                 “Managing Computer System 
                 08/943,356 
                 MNFRAME.033A 
               
               
                 Alerts” 
               
               
                 “Computer Fan Speed Control 
                 08/940,301 
                 MNFRAME.034A 
               
               
                 System” 
               
               
                 “Computer Fan Speed Control 
                 08/941,267 
                 MNFRAME.035A 
               
               
                 System Method” 
               
               
                 “Black Box Recorder for 
                 08/942,381 
                 MNFRAME.036A 
               
               
                 Information System Events” 
               
               
                 “Method of Recording Informa- 
                 08/942,164 
                 MNFRAME.037A 
               
               
                 tion System Events” 
               
               
                 “Method for Automatically 
                 08/942,168 
                 MNFRAME.040A 
               
               
                 Reporting a System Failure in a 
               
               
                 Server” 
               
               
                 “System for Automatically 
                 08/942,384 
                 MNFRAME.041A 
               
               
                 Reporting a System Failure in a 
               
               
                 Server” 
               
               
                 “Expansion of PCI Bus Loading 
                 08/942,404 
                 MNFRAME.042A 
               
               
                 Capacity” 
               
               
                 “Method for Expanding PCI Bus 
                 08/942,223 
                 MNFRAME.043A 
               
               
                 Loading Capacity” 
               
               
                 “System for Displaying System 
                 08/942,347 
                 MNFRAME.044A 
               
               
                 Status” 
               
               
                 “Method of Displaying System 
                 08/942,071 
                 MNFRAME.045A 
               
               
                 Status” 
               
               
                 “Fault Tolerant Computer System” 
                 08/942,194 
                 MNFRAME.046A 
               
               
                 “Method for Hot Swapping of 
                 08/943,044 
                 MNFRAME.047A 
               
               
                 Network Components” 
               
               
                 “A Method for Communicating a 
                 08/942,221 
                 MNFRAME.048A 
               
               
                 Software Generated Pulse 
               
               
                 Waveform Between Two Servers 
               
               
                 in a Network” 
               
               
                 “A System for Communicating a 
                 08/942,409 
                 MNFRAME.049A 
               
               
                 Software Generated Pulse 
               
               
                 Waveform Between Two Servers 
               
               
                 in a Network” 
               
               
                 “Method for Clustering Software 
                 08/942,318 
                 MNFRAME.050A 
               
               
                 Applications” 
               
               
                 “System for Clustering Software 
                 08/942,411 
                 MNFRAME.051A 
               
               
                 Applications” 
               
               
                 “Method for Automatically 
                 08/942,319 
                 MNFRAME.052A 
               
               
                 Configuring a Server after Hot 
               
               
                 Add of a Device” 
               
               
                 “System for Automatically 
                 08/942,331 
                 MNFRAME.053A 
               
               
                 Configuring a Server after Hot 
               
               
                 Add of a Device” 
               
               
                 “Method of Automatically 
                 08/942,412 
                 MNFRAME.054A 
               
               
                 Configuring and Formatting a 
               
               
                 Computer System and Installing 
               
               
                 Software” 
               
               
                 “System for Automatically 
                 08/941,955 
                 MNFRAME.055A 
               
               
                 Configuring and Formatting a 
               
               
                 Computer System and Installing 
               
               
                 Software” 
               
               
                 “Determining Slot Numbers in a 
                 08/942,462 
                 MNFRAME.056A 
               
               
                 Computer” 
               
               
                 “System for Detecting Errors 
                 08/942,169 
                 MNFRAME.058A 
               
               
                 in a Network” 
               
               
                 “Method of Detecting Errors 
                 08/940,302 
                 MNFRAME.059A 
               
               
                 in a Network” 
               
               
                 “System for Detecting Network 
                 08/942,407 
                 MNFRAME.060A 
               
               
                 Errors” 
               
               
                 “Method of Detecting Network 
                 08/942,573 
                 MNFRAME.061A 
               
               
                 Errors”