Unit 3

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Unit 3Part AComputer Memory
Computer Technology (S1 Obj 2-3)
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Memory

• Memory The area in the computer that temporarily
  holds data waiting to be processed

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RAM

• RAM stands for Random Access Memory
• It is the memory that holds your data as you
  process it.
• The data stays in RAM until you save it.
• RAM is volatile which means temporary memory, it
  cant hold data when the power is off.
• Data is lost if the computer looses power.

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RAM continued

• The more RAM you have, the more multitasking you
  can do on your computer.
• If you don't have enough RAM, you may notice that
  your computer is sluggish when you have several
  programs open.
• Many people add extra RAM to their computers to
  improve performance.

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ROM

• ROM stands for Read Only Memory.
• ROM contains the instructions the computer uses
  when it boots up.
• Because the data is read only, it can be read
  but not changed by the user.
• The data is not erased when the computer is
  switched offthe data is stored permanently. This
  is called non-volatile memory
• Therefore, ROM is permanent memory

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Binary Code

• Binary code is the language that computers use to
  communicate and process information.
• It is a coding system using the 0 and 1 to
  represent a letter, digit, or symbols in a
  computer or other electronic device.

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BIT

• Each 0 or 1 is called a bit.
• A bit is the smallest unit of information that a
  computer handles
• A single bit conveys little meaningful
  information

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BYTE

• A combination of eight bits is called a byte.
• One byte (8 bits) represents a single letter,
  symbol, or digit.

A 2 letter word 2 bytes, 16 bits
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Kilobyte

• One kilobyte (KB) is equal to 1,024 bytes
• Kilo is a prefix meaning thousand
• Kilobyte Approximately one thousand bytes
• Most of the user data stored in a computer, such
  as simple e-mail messages or a text file,
  occupies storage space of a few kilobytes

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Megabyte

• One megabyte (MB) 1,000 KB
• Mega Million
• Megabyte Approximately one million bytes
• The amount of information contained in 1 MB is
  approximately equal to one complete textbook.

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Gigabyte

• One gigabyte (GB) 1,000 MB
• Giga Billion
• Gigabyte Approximately one billion bytes
• Some videos stored on a computer can occupy more
  than 1 GB of space.

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Terabyte

• One terabyte (TB) 1,000 GB
• Tera Trillion
• Terabyte Approximatelyone trillion bytes
• Let's assume we're storing text from magazine
  pages. At an average 5,000 characters per page,
  1TB of disk space could hold 220 million pages of
  text!

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Petabyte

• Petabyte (PB) approximately one quadrillion
  bytes
• Google processes approximately 24 petabytes of
  data each day.
• ATT transfers approximately 30 petabytes of data
  through its networks each day.

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Exabyte

• Exabyte (EB) approximately one quintillion
  bytes
• In the next decade, astronomers expect to be
  processing 10 petabytes of data every hour from a
  telescope called the Square Kilometer Array
  (SKA).
• The telescope is expected to generate
  approximately one Exabyte every four days of
  operation.
• IBM is currently designing hardware to process
  this information

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