Secondary Storage Chapter 6 By Chris Fry 3

Secondary Storage Chapter 6 By Chris Fry

3 Main Types of Secondary Storage • Floppy Disks • Hard Disks • Optical Disks

Floppy Disks • A portable or removable storage media. • Used in word processing, spreadsheet and other types of files. • Also called flexible disks and floppies. • Often called disketts.

Today’s Standard • Most widely used floppy disk is the 1. 44 MB 3 ½-inch disk, labeled 2 HD, which means “two-sided, high density. ” • They can store the equivalent of 400 typewritten pages. They also have a writeprotect notch. When the notch is open, data cannot be added on the disk.

Tomorrow’s Standard Floppy • Floppy-disk cartridges- these disks are also 3 ½-inch; however, they are thicker and require special disk drives. • The three best known are Zip disks, Super. Disks, and Hi. FD disks.

Zip disks: • Have 100 MB or 250 MB capacity, over 170 times as much as today’s standard floppy disk. • Have internal zip drives. • Produced by Iomega. • Believed to be the next floppy disk standard.

Super. Disks: • Produced by Imation. • Have a 120 MB capacity, and are able to read and store data on the standard disk. Zip disk drives cannot. • Most popular for use with notebook computers.

Hi. FD disks • Made by Sony Coporation. • Have a 200 MB capacity. • Similar to Superdisk drives, they are able to be used with standard disks.

Will one of these replace today’s standard floppy? • There is no doubt that the standard floppy will become second to one of these other disks. • What is less certain is when this will occur.

Parts of a Floppy Disk • Data is recorded on a disk on rings called tracks. • • • These tracks are closed concentric circles, not a single spiral as on a phonograph record. These have no visible grooves. Each track is divided into visible wedge-shaped sections known as sectors. These form the interior of the disk. The plastic on the outside is just for protection.

Hard Disks • Use thicker, ridged metallic platters. • Able to retrieve and store information much faster and have a greater capacity. • Very sensitive • There are three types of hard disks: internal hard disks, hard-disk cartridge, and hard disk pack.

Internal Hard Disks • Known as a fixed disk because it is location • • • inside the system unit. Used to store programs and large data files. Consists of one or more metallic platters sealed inside a container. Advantages over floppy disks include: capacity and speed. An 80 -gigabyte internal hard disk can hold as much information as 56, 000 regular floppies.

Hard-Disk Cartridges • Easy to remove. • Used primarily to complement an internal hard disk, protect and secure information. • Have typical capacities up to 2 gigabytes. • Two well known include Jaz from Iomega and Spar. Q from Sy. Quest. • PC Card hard disks are used for notebook computers.

Hard-Disk Packs • Removable storage devices used to store massive amounts of information. Their capacity far exceeds the other types of hard disks. • Used by banks and credit card companies to record financial information.

Optical Disks • Can hold over 17 gigabytes, which is the equivalent of over several million typewritten pages or a medium-sized library on a single disk. • Uses laser-beam technology, which alters the surface of a plastic or metallic disk to represent data. • Uses reflected light, rather than 1 s and 0 s.

Future of Secondary Storage • There is no doubt that as time passes on storage will become faster and data will be stored in mass quantities. The more these technologies improve, the less restrictions we will have.