Date:	Sat, 13 Feb 93 21:56:22 PRT
From:	Jose Manuel Cerqueira Esteves <FESTEVES AT PTEARN DOT BITNET>
Subject:	Hyperdisk cache
To:	djgpp AT sun DOT soe DOT clarkson DOT edu

Greetings

Two months ago, I tested the Hyperdisk disk cache on a 80486 (33MHz, Trident
SVGA (1M), ISA bus, 125 Mb Seagate IDE drive, 8Mb of RAM, running MS-DOS 5.0,
using HIMEM.SYS but not EMM386 or other memory manager)
and had no problems using several programs running in protected mode:
emTeX, DJGPP (and pprograms compiled with it), Mathematica, ...
My hard disk had two partitions, one with approx. 100 Mb and the other with
approx. 25 Mb.

One day I FDISKed the hard disk in order to have only ONE partition,
and then I started to have the following problems:

 - with emTeX, (especially when processing complex documents)
   the computer sometimes hangs with the message

      Nonmaskable interrupt (NMI) at 000F:000230F4

                                             (or other address...)

 - with GCC (DJGPP) or programs compiled with it, execution sometimes
   stops with the following error message:

      Exception 2 (0x2) at eip=5bcde

                                    (or other address...)

   Alternatively, the cache detects an error, and deactivates itself.

(All this happens only when Hyperdisk is loaded).

Now I have a second hard drive (201 Mb), and altered the partitioning of the
first one. I now have:

 Disk 0:  C: ~102 Mb
          E: ~ 23 Mb

 Disk 1:  D: ~102 Mb
          F: ~ 99 Mb

and those errors continue to occur (with several versions of Hyperdisk,
including the latest, 4.52).

Documentation for emx (the DOS extender used by emTeX) suggests that the
NMI error may be due to RAM problems. However, I tested the memory
with several utilities and no errors showed up.

Has anyone met this problem before and found a solution for it?
By the way, which disk caches work well with DJGPP? Except for the above,
Hyperdisk has been quite reliable (I was going to register it just before
the above started to occur...).

Thank you very much for your help in advance


                           Jose Esteves

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