Date: Wed, 1 May 2002 20:50:28 +0100 (GMT/BST) From: Digby Tarvin <[EMAIL PROTECTED]> Subject: Re: [LIB] fdisk cannot partition 8.4gb
> > > >I measured the hibernation start as 8,373,335,040 on my 100CT, but the > >BIOS may be holding back a little more for some reason. Probably rounding > >to the nearest cylinder boundry according the the mapped geometry > >(multiple of 16065 sectors). Of course aligning to virtual cylinder > >boundries is completely pointless, but that is Microsoft for you.. > > Why do we keep talking about the 8GB boundary? Its the 1024 cylinder > boundary, it just so happens that most of the drives have the same number > of bytes per cylinder. Problem is you'll get bitten if you come across some > other drive with a different config that you're not aware of. Much safer > IMHO to just partition based on the cylinders (use Linux FDISK/CFDISK or > *gasp* Partition Magic if you want). Note that cylinder 1024 isn't the > limit of where you want to partition, its more like cylinder 1013 > (remember, the libretto can only SEE up to 1024 natively so it'll shove its > hibernation junk just before it). Perhaps a search of this list for the > numbers 1013 and 1014 will turn up some more info ... Not really. The DJSA-220 has a physical geometry of 16 heads and 63 sectors/track. A 1024 cylinder limit would cut you off at at around 500MB. To get around this, the BIOS uses a 'mapped' geometry of 255 heads, 63 sectors per track and 1024 cylinders - the limit imposed on all three quantities by the original IDE hardware interface. Thus the BIOS limit is 1024x255x63x512 = 8,422,686,720 regardless of the geometry of the drive. In the case of the DJSA-220 this gives access to the first 16383 cylinders out of a total of 38760. The drive actually has '16383 cylinders' printed on the label, indicating what the BIOS will see. > >You don't have to reserve space for the hibernation partion if using > >windows FDISK. It gets the drive size from the BIOS, which automatically > >subtracts what it needs. > > GAH! NO NO NO NO! ABSOLUPTLY NOT! > > Definitely not if you're using an overlay, otherwise I've had weird > problems with that on my 20 gig drive. I think its a combination of the > fact that booted into a DOS boot disk without overlay only sees 8 gig and > the fact that the Libby's BIOS by itself only seeing 1024 cylinders then > trying to figure out what to do with hibernation. Play it safe, do it > properly. You can't do it properly without fixing the BIOS. Anything else is a kludge, and can't be more than an educated guess which you need to confirm by forcing a hibernate and confirming that it goes where you expected.... What I was refering to was booting using booting the W95 that came with the machine and using the supplied FDISK. Not overlay, no third party tools, no alternate operating system. It then appears to treats it like an 8GB drive and leaves the hibernation space that would be appropriate for that circumstance. I have never used an overlay, because there is no way I would want to waste more the 8GB on Windows. > >That is the advantage of doing the FDISK on > >the Libretto rather than on a desktop. In fact it reserves 64M for > >hibernation, and an additional 12GB out of stupidity. > > Heh .. there's Windows for you. I just use Windows FDISK to create a 6 gig > partition (ie. well away from the hibernation partition, assuming 1024 > cylinders is around 8 gig) then use Partition Magic or Linux FDISK/CFDISK > to do the exact partitioning around the hibernation area (where you can see > and/or work in terms of cylinders). Or at least in multiples of 16065 sectors - not really cylinders. > >The point where you have to be careful is when you use a more powerful > >os which knows about the entire disk to allocate the space on the > >other side of the hibernation area. > > Umm ... you've lost me. My install of Win98SE on my libby can see the > partition that goes from the 18 gig to the 20 gig mark on my hard drive ... > I mean DOS FDISK lets you partition up to 8GB minus a bit. You can then use Linux FDISK etc to partition from the other side of the hibernation area (8GB plus a bit) to the end of the disk. In practice. having identified the where the BIOS thinks the disk ends, you probably want re-partition on both sides of the hibernation area. In my case, having used the second fdisk partition to determine the end of the disk as far as the BIOS is concerned, I booted Linux, removed the second partition and then created two more primary partitions within the 8GB area, and an extended partiton that went to the end of the disk. Then create logical drives, one of which straddles the hibernation area. > >Don't know about the 1137MB limit. Did you enable support for large > >disks when starting FDISK? > > 1137MB limit? Where did that come from? I'm intrigued ... > I see you found the reference in the original post. Regards, DigbyT -- Digby R. S. Tarvin [EMAIL PROTECTED] http://www.cthulhu.dircon.co.uk ************************************************************** http://libretto.basiclink.com - Libretto mailing list http://www.silverace.com/libretto/ - Archives -------TO UNSUBSCRIBE------- Reply to any of the list messages. The reply mail should be addressed to: [EMAIL PROTECTED] - Then replace any text on the message's subject line: cmd:unsubscribe --------TO UNSUBSCRIBE DIGEST------ Do above but with this on subject line: cmd:unsubscribe digest **************************************************************
