akcs.graf_e@tronsbox.UUCP (Graf Eberstein) (11/27/89)
A simple question to all (I think): I recently purchased a new computer, to replace my dead 80286 based AT. The new machine is an Advanced Logic Research (ALR) Model 386/220. It has one megabyte of 32 bit RAM onboard, supposedly. The question is this, and I somehow get the feeling that only people who know this machine would know this (but if you don't, and have ideas for answers, please...). Anyway, when the machine does a POST, it reads 640K RAM of BASE memory and 256K extended, which totals 896K, and not 1 meg (aka 1024K). In other words, where is the other 128K? There is a ROM to RAM copy function that can be dissabled by DIP switch, but the RAM is still not there if I do that. The machine passes every test imaginable, and all the RAM chips are the same type, and by convention should total 1024K. It has never been modified, etc. Further, if I reset the CMOS to reflect 384K extended, it gives a memory ammount error and insists that there's only 256K extended. Hints? Clues? Tips? Send me a reply here, or tack on to this message thread. Oh, some specifics on the hardware: BIOS is PHOENIX BIOS, dated 1/15/88 DOS is MSDOS v3.30 CPU is INTEL 80386 (22 MHz) No Co-processor installed Video is VEGA VIDEO-7 (VGA BIOS is dated 1988) HDC is a SEAGATE SCSI controller (also dated 1988)
unkydave@shumv1.uucp (David Bank) (11/28/89)
The only thing I can thing of, offhand, is that your machine is
reserving the 128 KB of RAM regardless of the setting of the
ROM-to-RAM DIP switch.
The main reason such a ROM-to-RAM copy is done is because
DRAM is so much faster than ROM chips -- nature of the semiconductors
used. However, I should think that in such a scheme (and I could be
wrong, but the idea seems sensible to me) that such memory would
be, at least nominally, protected from writing once the transfer
is completed.
If this inhibition exists and is hardware based, then that might
explain why you can't use the 128 KB....the machine is "wired" such that
the memory is off-limits to "normal" usage at all time, regardless of
the ON/OFF state of the ROM-to-RAM copy.
Anyway, this is a lot of guesswork, I admit. I worked on an
NCR '386 clone that had this "problem". It seems to me that
"1 MB RAM" should mean 1 meg of USER memory, that the user can
access freely...rather than 128 KB being hogged by the system and
the user being locked out. That, to me, is not 1 MB RAM.
Hope I've given you some ideas.
Unky Dave
unkydave@shumv1.ncsu.edu
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