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The amount of disk space that must be available for page storage is related to the maximum number of processes$,\: n,$ the number of bytes in the virtual address space, $v,$ and the number of bytes of $RAM,\: r$. Give an expression for the worst-case disk-space requirements. How realistic is this amount?
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Answer:

The total virtual address space for all the processes $=\mathrm {nv}$

$\therefore $ amount of storage needed for pages $ = \mathrm {nv} $

If an amount $\mathbf r $ is in the RAM, then the disk storage required $=\mathrm {nv-r}$

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