_Swapable memory">
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A swapable block has the flag HF_FIXED set to zero and HF_SWAPABLE set to one. If a block is marked &quot;swapable,&quot; the memory manager has the option of swapping it out of main memory (either to the hard disk, or to extended or expanded memory) when it is unlocked. This keeps space on the global heap free for other requests. If an application tries to lock a block which has been swapped out of main memory, the memory manager will copy the entire block back to the global heap, 