The Computer Revolution/Hardware/storage
From Wikibooks, the open-content textbooks collection
Contents |
[edit] 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.
[edit] 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 It has been superseded by flash-drive systems as well as rewritable CDs and DVDs, and is fading in popularity.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.
[edit] 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). 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.
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.
[edit] 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.
[edit] 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.
[edit] 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.
trent jackson week 5
[edit] 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
[edit] 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 -
