Memory of a Computer
is any physical device that is capable of storing information whether it is
large or small and stores it temporarily or permanently. Memory can be either
volatile or non-volatile.
Volatile memory is a type of memory that loses its contents when the computer or hardware device is switched off. RAM is an example of a volatile memory. Non-volatile memory is a memory that keeps its contents saved even in the case of power loss. ROM is an example of non-volatile memory.
Characteristics of Main Memory
·
Known
as the main memory.
·
Semiconductor
memories.
·
Faster
than secondary memories.
·
A
computer cannot run without the primary memory.
·
It
is the working memory of the computer.
·
Usually
volatile memory.
· Data is lost in case power is switched off.
Units of Memory
A computer processor is made up of multiple decisive circuits, each one of which may be either OFF or ON. These two states in terms of memory are represented by a 0 or 1.A group of eight bits is known as a byte. 1 byte can represent numbers between zero (00000000) and 255 (11111111), or 28 = 256 distinct positions.
Types of various Units of Memory-
Byte
In computer systems, a unit of data
that is eight binary digits long is known as a byte. A byte is a unit that
computers use to represent a character such as a letter, number, or a
typographic symbol (for example, “h”, “7”, or “$”).
A byte is abbreviated with a big “B”
whereas a bit is abbreviated with a small “b”. Computer storage is generally
measured in multiples of the byte.
Kilobyte
The kilobyte is the smallest unit of memory measurement but greater than a byte. A kilobyte is 103 or 1, 000 bytes abbreviated as ‘K’ or ‘KB’. Kilobytes are mostly used to measure the size of small files. For example, a simple text document may contain 10KB of data and therefore it would have a file size of 10 kilobytes.
Gigabyte
One gigabyte is equal to 1, 000 MBs and precedes the terabyte(TB) unit of memory measurement. It is abbreviated as “GB”. Gigabytes, are sometimes also abbreviated as “gigs, ” and are often used to measure storage device’s capacity. e.g., a standard DVD drive can hold 4.7 GBs of data.
Terabyte
One terabyte is equal to 1, 000 GBs and precedes the petabyte(PB) unit of memory measurement. It is abbreviated as “TB”. HDDs are measured in Terabytes e.g., a typical internal HDD may hold 2 Terabytes of data whereas some servers and high-end workstations that contain multiple hard drives may even have a total storage capacity of over 10 Terabytes.
Petabyte
One petabyte is equal
to 1, 000 TBs and precedes the Exabyte unit of memory measurement. It is
abbreviated as “PB”. Internet Giants like Google and Facebook store more than
over 100 PBs of data on their data servers.
Exabyte
One Exabyte is equal
to 1, 000 PBs and precedes the zettabyte unit of memory measurement. An Exabyte
is abbreviated as “EB”. The Exabyte unit of memory measurement is so large,
that it is not used to measure the capacity of storage devices. Even the data
storage capacity of the biggest cloud storage centers is measured in Petabytes,
which is a fraction of 1 EB.
Zetta Byte
One zettabyte is
equal to 1, 000 exabytes .A zettabyte is abbreviated as “ZB”. One zettabyte
contains one billion TBs or one sextillion bytes which means it will take one
billion one terabyte hard drives to store one zettabyte of data. Generally,
Zettabyte is used to measure the large amounts of data and all the data in the
world is just a few zettabytes.
Yotta Byte
One yottabyte is
equal to 1, 000 zettabytes. It is the largest SI unit of memory measurement. A
yottabyte is 1024 ZettaBytes and is abbreviated as “YB”. 1 yottabyte
contains one septillion bytes which are exactly the same as one trillion TBs.
It is a very large number that humans can evaluate. There is no practical use
of such a large measurement unit because all the data in the world made of just
a few zettabytes.
Some Misconceptions
The size on a disk with one KB is 1024
Bytes although it signifies 1, 000 Bytes of data. It’s just the old standard
everyone remembers. The download speed Kbps is 1,000 Bits per second, not 1,024
Bits per second.
Tabular
Representation of various Memory Sizes
|
Name |
Equal To |
Size (In Bytes) |
|
Bit |
1
Bit |
1/8 |
|
Nibble |
4
Bits |
1/2
(rare) |
|
Byte |
8
Bits |
1 |
|
Kilobyte |
1024
Bytes |
1024 |
|
Megabyte |
1,
024 Kilobytes |
1,
048, 576 |
|
Gigabyte |
1,
024 Megabytes |
1,
073, 741, 824 |
|
Terrabyte |
1,
024 Gigabytes |
1,
099, 511, 627, 776 |
|
Petabyte |
1,
024 Terabytes |
1,
125, 899, 906, 842, 624 |
|
Exabyte |
1,
024 Petabytes |
1,
152, 921, 504, 606, 846, 976 |
|
Zettabyte |
1,
024 Exabytes |
1,
180, 591, 620, 717, 411, 303, 424 |
|
Yottabyte |
1,
024 Zettabytes |
1,
208, 925, 819, 614, 629, 174, 706, 176 |