Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

The motherboard is an ATC-2000 from A-Trend, a now defunct
manufacturer.

The chipset is the 430HX from Intel.

The BIOS is an Award Modular BIOS v4.51 PG dated 07-26-96. This BIOS
does not «see» beyond the 8 GB limit.

The hard disk is a Western Digital Caviar WD800 (80 GB).

Occasionally this system does not boot from the hard disk. It
displays:
«DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER».

When it does so, neither Ctrl+Alt+Del, the reset button nor the power
switch cure the problem, until it boots!

When it boots from the hard disk, it works apparently flawlessly.
However it never failed to boot from the diskette.

The hard disk does not seem to be the culprit because I get the same
result with a brand new Western Digital Caviar WD800 hard disk.

Even when the system does not boot from the hard disk, it «sees» the
hard disk as a 8 GB hard disk which is OK given the BIOS limitations:
only hard disk controller data is involved here.

When it did not boot, I used DFSDOS to try to read sectors. The
latter returns a 512-byte string of 0xFE. Why 0xFE rather than 0x00
or 0xFF? Can it give a clue?

Could the power supply be defective? I checked both the +5 V and the
+12 V and they are within limits. Not having a storage oscilloscope,
I have been unable to test the timing of the Power Good signal with
the above two supply lines.

Is there a major flaw in the 430HX chipset?

Could it be a BIOS bug?

What puzzles me is that a supposedly deterministic system behaves as a
random system! I am well aware that this system has no commercial
value. Yet, I would like to find what is wrong with it...

Thank you for any suggestion.
--
Jean Castonguay
Électrocommande Pascal