Storage devices and media

• stored on chips and available immediately to CPU
• memory = primary storage

RAM (Random Access Memory): fast temporary memory where programs and data are stored only when the power is supplied.

• held on computer chip
• volatile memory because contents disappear when power is off
• read/write so canbe altered by the user

ROM (Read Only Memory): fast permanent memory used for holding instructions needed to start the computer up.

• held on computer chip
• non - volatile memory - does not lose contents when the power is switched off
• hold instructions to start computer
• contents cannot be altered by the user

Printer buffer: 'waiting room' for print jobs wait for printer to print them

The importance of having more memory:

• applications run faster on their own
• more applications can run at the same time
• can move quickly between applications

Uses of memory in computers and mobile devices:

• desktop, laptop, netbook computers - have large amounts of memory to run multimedia software and run many applications at the same time
• mobile phones - store programs and control phone e.g, games, address book
• PDAs, palmtops - store programs e.g, operating system, web browser software

Measured in bytes.

BIT = binary digit 0 or 1

BYTE = group of 8 bits

KILOBYTE = unit of file/memory size that is 1024 bytes

MEGABYTE = 1024 kilobytes

GIGABYTE = 1024 megabytes

TERABYTE = 1024 gigabytes