Strand 3: IT Systems

3.1 Hardware

Primary Storage RAM and ROM

ROM: Read-Only-Memory

RAM: Random-Access-Memory

ROM on a motherboard
ROM on a motherboard

Read-Only-Memory, or ROM, is a type of memory that can only give information, not store, hence the name. ROM is generally used for storing information that dosen't need to be changed. This is why you'll find ROM on motherboards of copmuters and inside of other small devices and also in video game cartiges. They'll will have stored the initial programs that would 'bootstrap' the computer, or abreviated to 'booting'. Also early home computers stored operating systems like BASIC on ROM as it was easier and cheaper than magnetic disks. ROM is used for booting the computer because it is non-volatile. This means that the information on the ROM stays there even if power is disconected from it. It is also still used as it used to be imposslbe to change, therefore protecting it from being erased.

There is ROM that can be bought blank and then programed, but only once. Also there are eraseable ROM (EROM) that can be changed, but is still quite difficult. The changing of the ROM is either through ultraviolet
light exposure on the EPROM (erasable programable ROM), or high electrical currentson the EEPROM (electrically erasable programable ROM). But now eletronic devices are now moving away from ROM.


Random-Access-Memory, or RAM, is a type of computer memory. RAM is a volatile type of memory meaning that once the power is disconected from it it won't retain the information. RAM is special in the fact that is can store information randomly and still retrieve it using circuitry.


This ramdom access makes RAM much faster than other computer memory, like a magnetic hard drive. A mangetic hard drive stores information on phyical space, meaning that it has to go and get it, thats why RAM is so much faster. Common RAM sizes these days are 1-2 GB for a basic computer. For a more powerful home computer it will be 4 GB. A destop computer can have up to 24 GB Using three sticks of 8 GB. Though developments in RAM speeds is mcuh slower than in CPUs, which means that proccessors are getting to fast for the RAM and has slowed down CPU development.