Is drive size determined by the BIOS or the OS?

[Kwad Guy]

I just noticed, reading the tech notes on the HP Website, that one
of the computers I have at work has a "BIOS" limition on IDE hard
drives of 65Gb. According to HP, the machine will boot with larger
drives (up to 130-ish Gb), but the BIOS will "limit" the drive size
to 65Gb.

So what does this mean? I assume that the OS relies on
the BIOS to determine the
hard drive size... If so, I guess this means you could use larger
hard drives, but the remaining capacity beyond 65Gb would be wasted.

Is this correct?

(I know the solution is to use a Promise or similar PCI IDE card,
but I'm trying to be sure that that workaround is necessary).

Kwad

 

[Priit]

Depends of the OS. Windows (at least Win9x, probably all others, too) will really use the size reported by BIOS and some room might go waste, but linux asks drive geometry directly from the HDD itself and can use it's full capacity even when BIOS fails to detect it right. Easiest way to avoid disc space wasting with Windows is to use disc translation programs by HDD manufacturer. AFAIK all HDD makers have released some kind of utils that allow you to write sth into drive's firmware that reports HDD's right size to the OS even when BIOS can't do that.

 

[Vincent]

I know that Linux can use the full capacity of large drives on older Pentium-class motherboards that don't recognize the full capacity of newer, large hard drives.