Re: Securing data in memory

Jim Adler (jadler@soundcode.com)
Tue, 13 Oct 1998 06:38:39 -0700

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> Will the driver actually secure an area of extended memory ? ... if
> so, would this memory totally bypass the Windows Virtual Memory
> Manager, or control it ?

I think using the term "secure an area of memory" is oversell. VnsmD
(non-swappable memory VxD -- BTW, we're open to name suggestions) simply
allocates (using VMM) and locks a page of memory so it never sees a swap
file. The
approach was to use the same criteria on the memory block as a block
allocated for DMA transfer (ie., contiguous, physically locked, etc.).

> Would other Windows applications be able to walk through (paging)
> secured memory ?

We haven't tested this, but my feeling is yes, especially for Win 3.1. If
another app knows the physical address, it can get at the memory. I'll look
into this more thoroughly, though.

Jim

=========
Jim Adler
Soundcode, Inc.
www.soundcode.com
425.739.2229 (voice)
425.739.2228 (fax)

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