On Sat, 27 Dec 2003, Krikket wrote: > On Sat, 27 Dec 2003, Christopher K. Johnson wrote: > > Krikket wrote: > > > > >Has anyone else had problems getting Fedora to recognize their hard drives > > >at full capacity? I have a 20 gig drive that the BIOS recognises as .. > > How are you checking the disk size under Linux? > > If as root you enter this command what do you get? > > > > dmesg|grep sectors > > Odd. That *did* show the full drive. I got the errant value during the > install. Depending on the BIOS and the BIOS settings this initial BIOS related disk size issue is common. As long as your bootstrap partition is located in the beginning of the disk (for you, inside the first 2GB) you will be OK and no change is needed. i.e. don't fix it -- when it ain't broken. Once Linux is booted, the limitations of the BIOS can be left behind as Linux drivers take over. Common magic BIOS disk limit numbers are 528MB, 2.1GB, 8.4 GB, 32GB, 64GB.... you should be able to read more about this topic on your disk drive vendors support pages. Some mother board vendors have BIOS updates available. With older BIOS versions and new monster disks it is often necessary to set (force) the C/H/S to some sane value to get the bootstrap loader to load. This is because the BIOS auto detect overflows small values and strange stuff happens. Also, you might have these BIOS values set strangely by a previous hardware adventure or a previous owner. >From a western digital support page. BIOS Dates May not support prior to drives larger than Aug 1994 528MB Feb 1996 2.1GB Jan 1998 8.4GB Jun 1999 32GB HINT: I was once told back in RH5/6 time to keep bootstrap stuff at the beginning of the disk. I think this still applies. Question: One thing I do not know is what happens when a file system much bigger than the BIOS limit is the location of bootstrap code. At first the initial location on the disk is going to be within the reach of the BIOS but a later updates on a full disk might place blocks of data for the new kernel beyond the reach of the BIOS. I believe the defaults in the auto partition RH code makes this a non question but still I am curious. A rescue Floppy or FC1-Disc1 would boot, but how to recover is unclear. BTW: What are your partitions? # cat /proc/partitions -- T o m M i t c h e l l mitch48 -a*t- yahoo-dot-com
