Page 54 - DCAP101_BASIC_COMPUTER_SKILLS

Unit 4: Secondary Storage Devices

Notes
Figure 4.3: A Flash Drive (pen drive)

Figure 4.3 shows a flash drive. It has a main body and usually a port connector cover. The
cover is removed or port connector is pushed out when the drive is to be plugged into the
USB port of’ a computer. The main body usually has a write protect tab, a read/write LED
(Light Emitting Diode) indicator, and a strap hole. Some manufacturers also provide software
to be used with the drive.

4.1.2 Optical Disk Drive
An optical disk is mounted on an optical disk drive for reading/writing of information on
it. An optical disk drive contains all the mechanical, electrical, and electronic components
for holding an optical disk and for reading/writing of information on it. That is, it contains
the tray on which the disk is kept, read/write laser beams assembly and motor to rotate
the disk. Figure 4.4. shows an optical disk drive.

Figure 4.4: Optical Disk Drive

Access Time

Optical disk drives are slower (have larger access time) than magnetic disk drives due to
following reasons:
1. The sectors of an optical disk are arranged on a continuous spiral track. This data
organization results in slower random access of a sector than the concentric tracks
organization (used by magnetic disks) because in case of concentric tracks, sectors are
always found on a given track at a fixed distance from the center.

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