Hardware · 4 question types
Past paper frequency (2018 to 2024)
This topic accounts for approximately 5% of your exam marks.
RAM vs ROM and primary vs secondary storage comparisons appear regularly.
Virtual memory is an area on secondary storage that the operating system uses as an extension of RAM when RAM is full.
Imagine a computer running so many programs that physical RAM fills up. Without some way to free RAM, the system would have to refuse to launch any new program. Virtual memory solves this by temporarily moving inactive data and instructions out of RAM and onto secondary storage, freeing space in RAM for whatever is currently active.
The operating system breaks RAM and virtual memory into fixed-size chunks called pages.
Virtual memory lets the computer keep working when RAM is full, but it has a cost:
The fix is straightforward: add more physical RAM so the system rarely needs to fall back on virtual memory.
Common misconception: virtual memory does NOT add to the physical capacity of RAM. It simply borrows space on secondary storage as a slow stand-in, used only when the real RAM is exhausted.