# The Computer Revolution/Hardware/Storage
## Types of Computer Storage

Before learning about what different storage devices are available, we need to have an understanding of the types of storage in a computer. The two types of storage are called primary and secondary storage. In devices that provide primary storage capability, the information is only stored temporarily and is easily accessible for processing. These are known as RAM chips (standing for “Random Access Memory”) and are connected to the motherboard as well as video cards. The devices that provide secondary storage capabilities are able to store information permanently, although the information that is stored is not as easily accessible as in primary storage but can still be accessed. Secondary storage devices would include hard drives, CDs, flash drives and the less common floppy disks. To distinguish the important difference between primary and secondary storage, think of being inside the kitchen of your own home. You are preparing a meal out of the family cookbook which you have laid out on top of your kitchen island along with your ingredients and tools sitting within reach. Your kitchen island is your primary storage because it keeps the items that you need to process within easy reach (you can think of yourself as the CPU) but those items do not remain there permanently. Your refrigerator, pantry and kitchen cabinets can be thought of as your secondary storage since items can be kept in these areas permanently, but would take more of your time when trying to cook a meal since you would have to search through them to find what you need.

## Floppy

A soft magnetic disk. It is called floppy because it flops if you wave it (at least, the 5¼-inch variety does). Unlike most hard disks, floppy disks (often called floppies or diskettes) are portable, because you can remove them from a disk drive. Disk drives for floppy disks are called floppy drives. Floppy disks are slower to access than hard disks and have less storage capacity, but they are much less expensive. And most importantly, they are portable. Floppies come in three basic sizes:
8-inch: The first floppy disk design, invented by IBM in the late 1960s and used in the early 1970s as first a read-only format and then as a read-write format. The typical desktop/laptop computer does not use the 8-inch floppy disk. 5¼-inch: The common size for PCs made before 1987 and the predecessor to the 8-inch floppy disk. This type of floppy is generally capable of storing between 100K and 1.2MB (megabytes) of data. The most common sizes are 360K and 1.2MB. 3½-inch: Floppy is something of a misnomer for these disks, as they are encased in a rigid envelope. Despite their small size, microfloppies have a larger storage capacity than their cousins -- from 400K to 1.4MB of data. The most common sizes for PCs are 720K (double-density) and 1.44MB (high-density). Macintoshes support disks of 400K, 800K, and 1.2MB.
Floppy disk at the time was the only option of removable storage. One major problem with the disk was it was flimsy and easily destroyed. If you touched the exposed area your data could be completely destroyed. You had to use extreme caution when handling it.
The floppy disk evolved to a slightly more durable storage medium. The problem with it was if the metal piece was moved it exposed the data to elements that would destroy the data saved.

## Zip

The Zip drive is a medium-capacity removable disk storage system, introduced by Iomega in late 1994. Originally it had a capacity of 100 MB, but later versions increased this to first 250 MB and then 750 MB.
The format became the most popular of the super-floppy type products but never reached the status of a quasi-standard to replace the 3.5-inch floppy disk. It has been superseded by flash-drive systems as well as rewritable CDs and DVDs, and is fading in popularity. The Zip brand was also used for internal and external CD writers known as Zip-650 or Zip-CD.

## Hard Drive

A hard disk drive (HDD, also known as hard disk, hard drive, or the now-near-obsolete terms fixed disk, fixed drive, fixed disk drive, hard file) is a digitally encoded non-volatile storage device which stores data on the magnetic surfaces of hard disk platters.
Hard disks were originally developed for use in connection with, or later inside, a single computer. Later, as a way of guarding against hard disk failure, they were arranged into configurations such as redundant array of independent disks (RAID). RAID is a method of storing data on two or more hard drives that work together. One common RAID technique which RAID1 uses is disk mirroring. Disk mirroring is when data is written to two duplicate hard drives at the same time. This way if one hard drive files, the date automatically moves to the other hard drive where you can access it. This technique greatly reduces the chance of loss of data and/or service.
Hard disks are also found in network attached storage (NAS) devices, but for large volumes of data may be most efficiently used in a storage area network (SAN). Over time, applications for hard disk drives have expanded beyond computers to include video recorders, audio players, digital organizers, and digital cameras. In 2005 the first cellular telephones to include hard disk drives were introduced by Samsung and Nokia.
The capacity of hard drives has grown exponentially over time. With early personal computers, a drive with a 20 megabyte capacity was considered large. In the latter half of the 1990s, hard drives with capacities of 1 gigabyte and greater became available. As of 2006, the "smallest" desktop hard disk still in production has a capacity of 40 gigabytes, while the largest-capacity internal drives are a 3/4 terabyte (750 gigabytes), with external drives at or exceeding one terabyte by using multiple internal disks. These new internal drives increased their storage capacities with Perpendicular recording.
The most traditional hard drives are magnetic hard drives, which contains one or more round pieces of metal coated with a magnetisable substance. These hard drives have heads which are used to store and retrieve the data, which directly attached to the access mechanism that helps the heads to move in and out over the surface of hard disk. Different types of hard drives are used for different type of computers. For example desktop computers use 2.5 inch or 3.5 inch hard drives, whereas mobile phones, portable digital media players and other small devices use 1.5 inch or smaller hard drives. But, no matter what the size of the hard drive is, each and every hard drive contains a stack of hard disk.
In recent years the development of network attached hard drives has also increased dramatically, this is commonly referred to as Network Attached Storage (NAS), it's most useful form is the storage area network (SAN) where a single computer hosts many disks and shares access to those disks (presents) them over the network, where they appear as if they were local to the client computer. A good example of this is given at Building A Low Cost SAN.
Solid state drives are a newer type of hard drive that contain no moving parts allowing data to be stored on flash memory technology. Solid state drives or SSDs come in smaller sizes, 64-256GB, compared to traditional hard drives. SSDs are becoming more popular as they perform several times faster than a traditional SSD and have become more popular in ultra light netbooks and notebooks. The prices for SSDs are also coming down as the flash technology becomes more advanced and keeps current with SATA 6Gbit/s speeds.

## External Hard Drive

External(portable) hard drives are usually powered by USB. The current capacity limit for a single magnetic hard drive(typical hard drive with moving parts inside) is 500 gigabytes, but a single external hard drive can utilize several internal disks and exceed one terabtye(1,024 gigabytes) of storage. The current capacity limit for SSD(solid state drive) hard drives is 128 gigabytes. External drives are useful for backing up data and keeping it safe.
Hybrid hard drives are composed of a standard magnetic hard drive and a solid state drive (see Flash Memory below). This configuration allows for increased performance, aka speed, of the drive while not sacrificing size. The use of a flash drive can significantly decrease the amount of time it takes for the computer to boot and load applications. These devices are more expensive than standard hard drives, but may be suitable for power users.
USB Flash Drive
USB flash drives sometimes called USB flash memory drives, thumb drives, or jump drives consist of flash memory media integrated into a self contained unit that connects to a computer or other device via a standard USB port and is powered via USB port. USB flash drives are designed to be very small and portable. In order to appeal to a wide variety of users, USB flash drives are available in a range of sizes, colors and appearances – including those designed to be attached to backpacks or worn around the neck, those built into necklaces, wristbands or wristwatches, those thin enough to fit easily into a wallet and those are made into custom shapes. When the USB flash drive is built into a consumer product such as watch, sunglasses or a Swiss Army knife, a retractable cord is used to connect the device to a computer when needed. They are used so widely, additional hardware related to USB flash drives are becoming available such as USB duplicator systems used by educators to copy assignments or other materials to and from a large collection of USB flash drives at one time. To Read or write, you just need to plug it into a USB port. If the USB flash drive is being used with a computer, then it is assigned a drive letter by the computer just like any other type of attached drive and files can be read from or written to the USB flash drive until it is unplugged from the USB port. The capacity of most USB flash drive today ranges from 1 GB to 64 GB. It is most useful to all students, employees to transport files from one computer to another as well as quickly backup important files.

## USB keys

USB keys are the new mobile storage unit. It is a flash memory stick with a casing that slides nicely into a computer's USB port for data transfer. USB keys can vary in size, smallest being the 32 MB and the max is currently 4 GB. It can carry any type of data such as your music files, word applications, and even powerpoint presentations, with little problems. USB keys are safer than their predecessors, the floppy drive and zip drive, in fact some USB keys have survived trips through washing machines! The USB keys are compatible to work with windows 98 or higher. They are also Mac and Linux compliant.

## Tape Drives

Tape drives research began in 1949 by IBM. The whole process was to find a suitable replacement for punch cards. The necessities being the replacement should be compact, faster, cheaper and reusable. The big difference between a tape drive and a audio cassette tape is in the machinery. The drives themselves are much quicker and more accurate than a home cassette player. The tapes store data in a continuous string of bits, also known as, sequential data, and the need to find a particular part of the information that is being searched for requires a mechanically efficient and accurate machine. They are able to fast-forward and rewind to a particular spot on the tape with high speed and accuracy. This is the image of the large reel-to-reel machines seen in old television and movies, and are still used today for their cost effectiveness for backups. Backups are the recording of data from a computer hard drive to another secondary storage device. Although compact discs are gaining in popularity, tape drives are still widely available. The improvement in tape drives has been dramatic since their inception. The original tape drive, IBM 701 Tape Drive, could store 100 bpi (bits per inch), run at a speed of 70 ips (inches per second) and could be as long as 1400 feet. Since then tapes have evolved to run 200, 556, 800, 1600, and even 6250 bpi. They run at greater speeds than original, and have lengths up to 3600 feet. Tape drives were at their prime up until the 1990's. Then the flexibility, speed, and storage abilities of hard drives overtook tape drives. As mentioned earlier, tape drives are still available, but are now relegated to inexpensive backups of vast amounts of data.

## Smart Cards

A smart card is a pocket-sized card with an embedded chip inside of it. There are many uses for these cards from printing applications, Identification, storing memory, credit card and banking. Smart Cards are also being used in SIMS for mobile phones, authorization cards for pay television, high-security identification and access-control cards, and public transport payment cards.
Recently smart cards are starting to be used as electronic wallets. The smart card chip can be loaded with funds which can be spent in parking meters and vending machines or at various merchants. SMart cards are highly effective with all the applications listed above as they are low in cost yet highly effective solution to handle data.
Smart cards store a small amount of data or for identification purposes. The increase in technology have greatly increase the capabilities for the smart cards. They can be used to enhance security at places like an office building. Smart cards are also used worldwide for student id cards. In some smart cards, there is even biometrics data in the card for an even higher level of security. Biometric data is used to ensure authenticity of the card’s user before the smart card releases any data to the user.
In order to use a smart card, you must insert the smart card into the card reader or place it near a card reader. Once the smart card have been verified, the user will be able to complete any transaction they want to make.

## Flash memory

Flash memory refers to a memory chip that holds its content without power and that can be electronically erased and reprogrammed without being removed from the circuit board, often used in fax machines. It is called Flash memory because the microchip is organized so that a section of memory cells are erased in a single action or "flash." Flash memory is used in digital cellular phones, digital cameras, LAN switches, PC Cards for notebook computers, digital set-up boxes, embedded controllers, and other devices.
There are three forms of flash memory: 1)flash memory card, 2)flash memory sticks and 3)flash memory drives. first of all, flash memory cards are also known as flash ram. It can be inserted in the memory port of the digital cameras, handheld Pc, or other mobile devices. Moreover, this flash cards are removable storage and it doesn't have processor. The second kind of flash memory is the flash memory stick that is small and holds more than one gigabyte of data. this is inserted into a memory stick port in different devices as digital cameras, camcorders, notebooks, PC among others. The last form is flash memory drive which is also called USB drive flash card. This is typically small, lightweight, removable and rewritable. It also holds more data, and may be more reliable. The capacity of storage is up to 2 gigabytes, so people do not have to carry their laptops, this flash card can be inserted into computer's USB port or USB hub

## Online secondary storage

Do you know that there is another way to storage information besides zip drive, memory stick, and floppy disk?. This is online secondary storage. People also can back up info using this service on internet. This way is utilized by companies to save their information as a backup. In the past, companies have lost lot of information when they experienced flood and fire. Some services are free, but another you have to pay. Some online storage companies offer internet backup as a service online. These companies are Driveway, Magical Desk and Backup among others. Online storage means that companies can storage confidential information in a safety way on internet and they will have a copy if they lost the original information. Also, this info can be shared with employees that are in different parts of the world and can be updated in anywhere. Some companies have decided to store information due to the fact that they are lost very important information due to virus, hardware theft, or when the software is not working properly. This storage is reliable, how does internet backup work? First, people have to buy a software and install it in its hard drive
Functionality - Online Backup, Remote Offsite Data Back-up via Internet: PerfectBackup UK -

## Holographic Storage

Holographic Storage is just what you can imagine it to be. A type of 3D storage system that records images/data on a holographic disk or cartridge. Why would you use this besides it sounding awesome? It's insanely fast and holds a lot of space. This is possible because this type of storage uses light to send data. One single flash of light holds over one million bits of data. This is what makes it fast and can hold a substantial amount. A hologram is also stored through the thickness of the medium. For example, a disk has a spiral track that holds its data. A hologram on the other had is layered over it almost like a stack of sliced cheese, except much more miniscule. So how is this done? A holographic drive splits the light it is receiving into two beams. The angle of the reference beam determines where the data will be stored. The other beam called the signal beam goes through a device (spatial light modulator) and translates the data in the light into a 3D model.
The image describes this process.
* Laser beam used to write or read data
* This is where the beam is split
* This is the reference beams path.
* This is where the signal beam passes through the spacial light modulator and translates the data
* This is where the data is read and it is projected onto a detector to be reconstructed

## Cloud Storage

Cloud storage is a remote storage device accessed through the internet. This storage can be accessed on demand therefore bringing convenience to you. There are some applications out there like Google Docs and Flickr where you can store things and access. Typically users of site like these would create an password protected account and choose files to be private or shared with specific individuals. This type of storage is increasing in users because of the availability of their files. They can log on to any computer or mobile device to access their files and this ensures that no matter where you are you have your important files with you. Online storage is also convenient because you can back up your files regularly therefore protecting your files even if your computer crashes. Most of these sites offer this type of storage for free.
Deployment
There are also different types of cloud deployment. There is a public cloud in which a provider make the storage accessible to the public either for free or at a fee. Private clouds are used by single organization and are only accessible to users granted access in that organization. Private clouds are either operated internally or externally depending on the organization's needs and capabilities. Community clouds are used by users over a number of organizations that have common concerns such as security, compliance etc. Hybrid models are made up of 2 or 3 of the different types of clouds but still remaining unique in their own opperations but offering communication between the different types without losing their original integrity.

## Further Reading

* The Computer Revolution/Hardware/RamChips