Hard Drives, Binary Codes and the Evolution of Storage Devices

HARD DRIVE

Compared to the RAM or Random Access Memory, the Hard Drive is a more permanent storage. The Hard Drive is considered as a non-volatile memory.  

The Hard Drive’s storage capacity is measured in bytes.

1 kilobyte = 1024 bytes

1 megabyte = 1024 kilobytes

1 gigabyte = 1024 megabytes

1 terabytes = 1024 gigabytes

BINARY CODES

The first computers used decimals, but because of practical reasons, they eventually used binary codes for computers. An example of binary codes is the Morse code.

It is practical because (1) a lot of the computer’s components already used binaries (e.g., electricity has positive or negative charges, magnetic components has north and south poles) (2) binaries are easier to process than decimals and (3) it is easy to interpret.

EVOLUTION OF STORAGE DEVICES FOR COMPUTERS

FLOPPY DISK (5 ¼”)

TYPES:

 Double density – 360 KB

 High Density – 1.2 MB

DISKETTE (3 ½”)

TYPES:

 Double density – 720 KB

 High density – 2 MB [1.44 MB (formatted for PC), 1.4 MB (formatted for Mac)]

CD (Compact Disk)

SIZE: 600 – 700 MB

CD-R (Compact Disk – Recordable)

CD-RW (Compact Disk – Rewritable)

DVD (Digital Video Disk)

SIZE: 4.7 Gigabytes (4.2 Gigabytes formatted)

FLASH DRIVE

EXTERNAL HARD DRIVE

CLOUD