Magnetic storage system is one of the three main categories of storage technologies in use today. With magnetic storage systems, data is written by read/write heads, which magnetize particles on the surface of the medium to represent the data’s 0s and 1s.
The particles always retain their magnetic arrangements until they are changed again, and so files can be rewritten to the disk and deleted as needed.
Magnetic storage system is one of the key storage systems used with today’s computers. This is due to their speedy access to data, relatively low cost, and the ability to erase and rewrite data. The most common types of magnetic storage systems are Hard disks, Floppy disks, Zip disks, and Magnetic tape.
Common Types Of Magnetic Storage Devices
Hard disk is a non-removable magnetic storage device included in most computers. It is a stack of aluminum or glass platters, each coated with iron oxide, enclosed in a hard disk drive. Similar to other magnetic storage devices, hard drives store data magnetically. They use read/write heads to store and retrieve data. Their disks are organized into tracks, sectors, and clusters.
A hard disk drive or hard drive consists of these components: hard disk platters, a spindle on which the platters spin, a read/write head for each side of each platter, cylinders (vertical stack of tracks), and a sealed chamber that encloses the disks and spindle.
There are different types of hard drive based on their location on the computer system. Some are internal, external, or portable. Internal hard drives are those located inside the system unit and are not designed to be removed, unless to be repaired or replaced. They are usually used to store most programs including the operating system, and data. External hard drives usually are connected to a computer through a USB or FireWire port. Desktop hard drives usually use 3.5 inches hard disks and notebook hard drives typically use 2.5 inches hard disks. Digital music players, mobile phones, and other mobile devices usually use 1.5 inches hard disk or smaller.
What is the storage capacity of a hard drive?
Hard drive capacities are best described in sizes according to the amount of data each can hold in bytes. Internal hard drives designed for desktop computers today typically hold between 80 GB and 1 TB or more. External hard drive capacity is even larger and can hold up to 250 GB.
|UNITS OF COMPUTER MEMORY MEASUREMENT|
|1 Bit||=||1 Binary Digit|
|8 Bits||=||1 Byte|
|1024 Bytes||=||1 KB (Kilobyte)|
|1024 KB||=||1 MB (Megabyte)|
|1024 MB||=||1 GB (Gigabyte)|
|1024 GB||=||1 TB (Terabyte)|
|1024 TB||=||1 PB (Petabyte)|
|1024 PB||=||1 EB (Exabyte)|
|1024 EB||=||1 ZB (Zettabyte)|
|1024 ZB||=||1 YB (Yottabyte)|
Zip disks, introduced by Iomega Corporation in 1995, are magnetic disks used with their respective Zip drives. Zip disks are similar to floppy disks in appearance but are slightly larger and thicker in size. They have a capacity of 100, 250, or 750 MB. Zip disks are mostly used by people who need to back up large files or transfer large files between computers.
Magnetic tape consists of a thin, magnetizable coating on a long, narrow strip of plastic film on which data can be stored and retrieved. They are similar to the tape cartridges used in home videos and tape recorders. Mainframe computers and minicomputers use magnetic tapes mounted on reeds while microcomputers use tape cartridges and tape drives. Magnetic tapes are specifically used for backing up data.
Also, known as flexible disks, floppies, or diskettes, floppy disks are magnetic storage media made of a thin flexible circular film sheet enclosed in a plastic protective cover. Microcomputers have traditionally been set up to use floppy disks for removable storage needs. Floppy drives are used to write to and read from floppy disks.
Two common sizes of floppies used with microcomputers are 5¼ inch floppy and 3½ inch floppy. The storage capacities of the 5¼ inch floppies ranged from 180KB to 1.2MB. The 3½ inch floppies could store between 720KB to 1.44MB of data. Diskettes have been made obsolete since the early parts of the 21st century by other removable storage devices like Compact discs (CDs) and Flash drives. Currently floppy disks are no longer used with microcomputers.