Virtual memory is the mechanism
by which more memory can be allocated
than is physically present in the machine.
This is enabled by paging small
(4KB) pages of memory from main memory
to a swap area on hard disk
when they are not needed.
These pages can be paged in on demand
when referenced at a later time.
Since program code will not be modified,
it need not be paged out
but is instead demand-paged in from the filesystem as required.
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