Units of measurement for information in computers

This post is lesson 8 of 42 in the subject Computer Hardware

Bit is the basic unit of measurement of information. In addition to bits, there are many other units of measure. This article will introduce the basic units of measurement in computers.

1. Bit – BInary digiT (b)

Bit is the smallest unit of data stored in a computer. All data must be encoded in bits for the computer to understand. A binary digit has 2 states: 0 or 1.

2. Byte (B)

A byte consists of 8 bits. Byte (B) usually used to represent the capacity of data storage in the computer.

3. Conversion table between units of measurement

In addition to bits and bytes, we have larger units of measurement to meet the growing storage needs.

UnitShortenedCapacity (in decimal)Capacity (in binary)
Bitb0 hoặc 10 hoặc 1
ByteB8 bitxxxxxxxx bit
KiloByteKB103 B210 B = 1024 B
MegaByteMB103 KB210 KB
GigaByteGB103 MB210 MB
TeraByteTB103 GB210 GB
PetaBytePB103 TB210 TB
ExaByteEB103 PB210 PB
ZettaByteZB103 EB210 EB
YottaByteYB103 ZB210 ZB

Note, depending on the definition, we have 1 KiloByte (KB) equal to 1000 Bytes or 1024 Bytes. Hard drive manufacturers often use of decimal in measuring the capacity (1 KiloByte (KB) equals 1000 Byte) to represent the storage capacity of hard drives. This explains, a drive has a capacity of 500 GB but the actual amount of storage is always less than 500 GB.

Hard drive capacity

3. Hertz (Hz)

Hertz (Hz) is a unit used to measure the processing speed of the CPU in a computer. The larger this value is, the higher the computer’s processing speed. Processing speed of CPU is usually measured in Megahertz (MHz), Gigahertz (GHz).

HerztHz1 Hz
KilohertzKHz1000 Hz
MegahertzMHz106 Hz
GigahertzGHz109 Hz
TerahertzTHz1012 Hz

4. bit per second (bps)

bps is a unit of measurement of data transfer rate (DTR) per second in bits. And Bps (Bytes per second) is a unit of measurement of data transfer rate per second in Byte. The transfer rate can be the transfer rate between CPU and RAM, between computers on the network, etc.

Note, the bit symbol is the letter b (lowercase b), the Byte symbol is the letter B (uppercase B).

NameSymbolData transfer rate
Bit per secondbps1 bps
Byte per secondBps8 bps
Kilobit per secondKbps1000 bps
Megabit per secondMbps1000 Kbps
Gigabit per secondGbps1000 Mbps
Kilobyte per secondKBps8.1000 bps
Megabyte per secondMBps8.1000 KBps
Gigabyte per secondGBps8.1000 MBps

1 Byte = 8 bit so 1 Bps = 8 bps, the same for KBps, MBps,…

5. Rotation speed of hard disk drive

With HDD (hard disk drive), the speed of the hard drive featured by RPM (revolutions per minute) which means the number of revolutions per minute. Today, hard disk drives typically have a rotational speed of 5400 RPM or 7200 RPM.

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Posted by Vinh Le

Composer at ITLearningCorner.

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