Page 53 - DCAP101_BASIC_COMPUTER_SKILLS

Basic Computer Skills

Notes 2. Disk Pack. It consists of multiple (two or more) hard disk platters mounted on a single
central shaft. All the disks revolve together at the same speed. Its disk drive has a
separate read/write head for each usable disk surface (recall that when multiple disks
are used together in a disk device, the upper surface of the topmost disk and the lower
surface of the bottommost disk are sometimes not used). Its disk drive is of
interchangeable type and allows loading/unloading of different disk packs as and
when they are to be used. When not in use, a disk pack is stored off-line in a plastic
case (see Figure 4.2). This gives virtually unlimited storage capacity to disk packs.

3. Winchester Disk. A Winchester disk consists of multiple (two or more) hard disk platters
mounted on a single central shaft. However, unlike a disk pack drive, a Winchester disk
drive is of fixed type That is, its hard disk platters and disk drive are sealed together
in a contamination-free container and cannot be separated from each other. Hence,
Winchester disks have limited capacity. However, for the same number of disk platters
of the same size. Winchester disks can have larger storage capacity than disk packs due
to following reasons:
(a) As both disk platters and disk drive are permanently sealed together, all surfaces
of all disk platters (including the upper surface of the topmost platter and the
lower surface of the bottommost platter) are used for data recording in a
Winchester disk. That is. For a Winchester disk with four platters there are eight
usable surfaces as opposed to six surfaces in case of a disk pack with four
platters.

(b) The contamination-free environment allows Winchester disks to employ greater
precision of data recording and accessing, resulting in greater data storage density
than interchangeable disk packs.
Winchester disks were so named after the 30-30 Winchester rifle because the early Winchester
disk systems had two 30-MB disks. Storage capacity of today’s Winchester disks ranges from
9
a few tens of megabytes to a few gigabytes (l0 bytes).
4.1.1.2 Flash Drive (Pen Drive)
Flash drive is a compact device of the size of a pen, comes in various shapes and stylish
designs (such as pen shape, wallet shape, etc.), and may have different added features (such
as with a camera, with a built-in N1P3lWMA/FM Radio play back for music on the go, etc.).
It enables easy transport of data from one computer to another. It is a plug-and-play device
that simply plugs into a USB (Universal Serial Bus) port of a computer. The computer detects
it automatically as removable drive. Now one can read, write, copy, delete, and move data
from the computer’s hard disk drive to the flash drive or from the flash drive to the hard
disk drive. One can even run applications, view videos, or play MP3 files from it directly.
Once done, it can be simply plugged out of the USB port of the computer and kept into the
pocket for being carried anywhere. A flash drive does not require any battery cable, or
software, and is compatible with most PCs, desktop, and laptop computers with USB 2.0 port.
All these features make it ideal external data storage for mobile people to carry or transfer
data from one computer to another. As the name implies, it is based on flush memory storage
technology Recall that flash is non-volatile, Electrically Erasable Programmable Read Only
Memory (EEPROM) chip. It is a highly Aid-state storage having data retention capability of
more than 10 years.
Available storage capacities are 8MB, 16MB, 64MB, 128MB, 256MB, 512MB, 1GB, 2GB, 4GB,
and 8GB. A : of 16MB capacity has 5600 times more storage capacity than a IAMB floppy
disk.

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