386 upgrade boards for IBM 5160s

[Fred Cisin]

> > BUT, 3.10 wants HIMEM.SYS, and will refuse to install unless there is some
> > "extended" (NOT "expanded") RAM above 1M.

On Tue, 3 Nov 2009, Sridhar Ayengar wrote:
> 3.1 wants HIMEM.SYS, but it most decidedly doesn't require memory above
> 1MB.  It does require memory above 640kB.  But 1MB memory works just fine.

It is certainly true that you do not need to have MORE THAN 1MB.
In order to get Windoze 3.10 with 1MB to work, I had to configure it so
that 384K (or even just 64K) was seen as having address above 1M.  The
botom 640K does not need to be fully populated - one of my 3.10 ATs had
512K starting at address 0h, and another 512K (surely could have used 64K)
starting at address 10000h
HIMEM.SYS, and consequently Windoze 3.10 require a working A20 line, and
at least SOME memory accessed with a 1 in A20.