# Memory Units of a Computer

A computer processor is made up of many electronic circuits that start working from the time we boot the computer. These logical circuits have to be in one of the states ie, ON or OFF. These two states in computer terminology are represented by the binary form of 0 or 1.

A Memory Unit of a computer can be described as any physical storage unit that is capable of storing and processing this binary information in a group of bits called Words.

A Bit aka Binary Digit is the most basic unit of information representing logical 0 and 1 ie, a passive or an active state (on/off) of a component in an electric circuit.

Simply put, it can be considered as building blocks of information representing the two states - Yes or No. Whereas a Byte can represent 256 states of information with numbers, characters, or a combination of both.

The Bit is the smallest Unit and Geop Byte is the largest unit.

### Processor or Virtual Storage Units

```1 Byte = 8 bits
1 Nibble = 4 bits
1 Crumb = 2 bits
1 Kilo Byte (KB) = 1024 Bytes
1 Mega Byte (MB) = 1024 KB
1 Giga Byte (GB)  = 1024 MB
1 Tera Byte (TB) = 1024 GB
1 Peta Byte (PB) = 1024 TB
1 Exa Byte (EB) = 1024 PB
1 Zetta Byte (ZB) = 1024 EB
1 Yotta Byte (YB) = 1024 ZB
1 Bronto Byte (BB) = 1024 YB
1 Geop Byte (GpB/GeB) = 1024 BB```

## Digital Electronics Number System

In the digital computer, there are various types of number systems used for representing information. The different types of number systems employed are:
• Binary systems,
• The base of Binary number systems 2 (0 and 1)
• Decimal systems,
• The base of Decimal number systems: 10
• The base of Hexa Decimal number systems16 (0-9 and A to F)
• Octal Systems
• The base of Octal number systems: 8

### Conversion Table - Decimal, Hexadecimal, Octal, Binary

`   Decimal      Binary     Octal      Hexadecimal      0          0000        0             0      1          0001        1             1      2          0010        2             2      3          0011        3             3      4          0100        4             4      5          0101        5             5      6          0110        6             6      7          0111        7             7      8          1000       10             8      9          1001       11             9     10          1010       12             A     11          1011       13             B     12          1100       14             C     13          1101       15             D     14          1110       16             E     15          1111       17             F`

• One's complement in the Binary system can be obtained by – Changing its 1's to 0's and 0's to 1's
• Two's complement in the Binary system can be obtained by – Converting the value to its complement and add 1 to the complement

#### SideNotes:

• Mathematics employed in the computer – Boolean Algebra
• Nibble – Half a Byte, 4 bits (Previous PSC Questions – FCI 2015, Bevco Assistant Grade-II, 2015)
• 1 megabyte is equal to __ bytes – 106 (Previous PSC Questions – KSRTC 2015)
• ____Gigabytes = 1 Terabyte –1024 (Previous PSC Questions – Computer Assistant Grade-II, 2016)
• A quarter byte was called Crumb, used in early computing