Clive Backham wrote:
> On 17 Aug, 23:38, "OldMan" <old...@spoofmail.nothere> wrote:
>> Tried a repair installation of win?
>> Thats usually required after a mobo change
>
> Thanks for the response. I tried a repair, but it didn't help.
>
> In the end I slapped in a spare hard disk I had lying around and did a
> fresh reinstall (this time WinXP SP2).
>
> Things are now almost OK - my last issue is figuring out why the IDE
> channels are only running in Multi-Word DMA Mode 2. (All my IDE
> devices are ATA-100 or better, so I'd expect to get UltraDMA Mode 5).
There was an issue, back in that era, with how the various motherboard
manufacturers provided BIOS interfaces to the ICH5 Southbridge.
The Southbridge has two IDE ribbon cable interfaces, plus a couple
SATA ports. The SATA ports can be thought of, in the same way as a
ribbon cable.
That means there are three sets of two disks possible.
Intel provides two modes to operate the ports. In "compatible" mode,
only four disks max can be used. This would be a mode suitable for
Win98 for example, but even WinXP should be able to use it (no reason
to do it, but it is possible). Compatible mode means using I/O space
mapped interfaces, and IRQ14 and IRQ15 handle the four disks. Intel
created that mode, so a Win98 system could boot without drivers.
The second mode is "enhanced" mode. All six disks can be used in this
case. The interfaces on the Southbridge are mapped to the PCI address
space (base address plus offset), and interrupts are assigned like any
other plug-in PCI card might do. Win98 doesn't have a PCI address space
driver, but WinXP does. And being in the PCI space, you can have a large
number of disks, which is why six are possible.
In the four disk case, the BIOS designer has to provide the user with
a way of selecting four of six disks. The three sets of two disks are
offered, but only two sets can be enabled in the compatible mode.
On one Asus motherboard, you could choose "enhanced", but also choose
to use the disk selection feature (i.e. a control that influences which
four of six disks). That control really shouldn't be doing anything,
but when it is used in the "enhanced" cases, one of the side effects of
its mistaken usage, was the IDE interfaces would only run at the slower
rates. That sounds consistent with your symptoms.
The Gigabyte BIOS interface is different than the Asus one. Looking
at it, I would suggest trying "On-Chip SATA" to [Manual], then
"SATA Port0 Configuration as" [Sata Port0], and
"SATA Port1 Configuration as" [Sata Port1].
The idea behind that selection, is to use the Enhanced mode of operation,
and try and enable all six disk interfaces, without doing anything
weird with respect to selecting four of six disks. It could be, that
with less than six disks used, and the BIOS "auto" mode, that the
BIOS is doing something goofy.
In terms of suggested procedure, go to the BIOS and record the current
settings in "Integrated Peripherals" on a piece of paper. Try the new
settings. If the computer will not boot, you can go back to "Integrated
Peripherals" and put back the settings that allowed you to boot.
A reference on the subject of the Southbridge ports, is here. This is
not required reading, but is something I found in the past, when researching
ICH5 (my current motherboard has one).
"ICH5 SATA Programmers Reference Manual"
http://www.intel.com/design/chipsets/manuals/252671.htm
Paul
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