Date: Thu, 27 Apr 2000 17:29:10 +0100 (GMT/BST)
From: Digby Tarvin <[EMAIL PROTECTED]>
Subject: Re: 12 Gig drive: Phantom Hibernation Zone
> >
> > Also, you don't want to have to re-format the disk just
> > because you have added more ram, so if reserves space for the maximum
> > amount of ram your machine can take. For the 100CT, it comes with
> > 32Mb and can expand to 64Mb, so a minimum of 64Mb is reserved.
> >
> 64 Mb for main memory + 2 Mb for Video memory
> + something else ?
>
You could be right. It is hard to say how much is actually used
and for what. It would be really nice if Toshiba documented such
things.
On my 4GB drive (MK4309MAT), the real capacity was:
4327MB 8944Cyl 15Hd 63spt
according to the BIOS/FDISK it was
8789Cyl 15Hd 63spt
so it has reserved 155 cylinders at 512x63x15 bytes per cylinder.
That means the amount the 100CT BIOS needs is somewhere between
71.1MB (74,511,360 bytes) and 71.5MB (74,995,200 bytes).
It may be hard wired to 155 cylinders and assuming that all
drives in use will have at least 14 heads, which would give
just over 66MB - enought for 64MB + 2MB as you suggest.
My original 2GB drive was MK2105MAT and was
2167MB 4200Cyl 16Hd 63spt
And I think the BIOS reported 4056 cylinders, which would be 144
cylinders reserved, corresponding to 74,317,824 bytes.
That suggests it is a magic number of sectors, rounded up to the
nearest whole number of cylinders.
>From the 4GB disk, the number of sectors required must be in the
range 145,531-146,475
>From the 2GB disk, the range is 144,143-145,152
These ranges don't quite intersect, so the bios seems to be using some
very obscure algorithm for deciding how many clinders are needed. Or
parhaps this area is used for some bad sector mapping as well, which
would require more space for larger drives.
Regards,
DigbyT
--
Digby R. S. Tarvin [EMAIL PROTECTED]
http://www.cthulhu.dircon.co.uk
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