Computer Memory

Computer Memory

1. ROM

   • Read only memory is used to store instructions that don't need to be changed during normal use
   • Data can only be read from ROM ROM is non volatile- it retains data even if the power is turned off

2. RAM

   • Random access memory is where the computer stores data and instructions when an application is running.
   • Data can be read from and written to RAM. RAM is volatile- if you turn off the power, data in RAM is lost

3. Cache Memory

   • Cache memory is very fast memory usually within the processor itself.
   • The cache speeds up processing by storing recently or frequently used instructions so that they do not have to be fetched from the main memory which is much slower.
   • As the cache becomes larger it takes longer to find the data and so it becomes slower. Therefore, it is split into different levels e.g L1 and L2 with the smallest nearest to the CPU storing the most frequently used instructions.

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