The Main Memory
RAM & ROM
Main Memory
Main memory is located inside the computer system, it can either have RAM or ROM. Main memory in today’s computers is on average around 4-8 Gb of RAM.
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People often get confused with the main memory and backing storage, Backing storage is outside the main processor, e.g. Hard Drives, CD/DVD drives, USB Flash Memory (Pen Drives).
RAM
This is where the operating system is stored; it also holds all programs and data.
ROM
ROM is used to store a small part of the operating system called the bootstrap loader.
Difference Between RAM & ROM
RAM: ( RANDOM ACCESS MEMORY)
- The processor can write to and read from RAM at high speed
- Data held in RAM can be changed
- All data in RAM is lost when the power is switched off.
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ROM: (READ ONLY MEMORY)
- Data is stored permanently in ROM
- Data is not lost when the power is switched off
- Data in ROM cannot be changed