HDD is a MEMORY. The way they works are nearly the same. They memorizing all your files as bit and they wait instructions to accessing. Is just the material and size are different. In RAM, no power everything is gone. in HDD no power files still there.
... Windows has a paging file which is where they start using the HDD to store what would normally be stored in memory, but its ineffective and generally slows your system to a crawl...
No point in using your hdd as memory anyways, otherwise we'd all have 300 gig of memory these days...
linux uses swap partitions..and win uses page file ...... virtual memory...
as for reverse app ....using RAM (as we know it static RAM) ... as HHD is posible through IRAM......
theoretically it`s posible but practically......hmmm..