Storage Devices lesson Notes

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RAM-loses power, loses data - quick storage of data

ROM-loses power, loses nothing

Flash memory- loses power, loses nothing

RAM

Motherboards only accept certain RAM

Double

Data

Rate

accesses 2 blocks of memory at a time, DDR2, DDR3 has faster memory

Single

Data

Rate

Data only accessed only one block at a time

therefore slower

Virtual memory

Uses the HDD to increase the amount of RAM avaliable.

sections called pages

Step 1

Data(on the RAM) not used for a while identified by OS

Step 2

This data is copied to HDD

Step 3

This space can then be used for something else

Virtual memory is slower than RAM, can slow the pc if overused

Overuse causes thrashing, where data is continuously swapped in and out

Higher Amounts of RAM means that more data can be stored. This means that the computer can run faster and multitask at the same time. It can play music and Web browse at the same time. The more RAM it has the easier this is.

Cache Memory

Virtual Memory has advantages and disadvantages. It allows the computer to have more RAM available for multitasking, improving performance. It does this by using the HDD to store data that has not been used in a while, freeing up more space. Unfortunately using it too much can slow down the computer

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