In <20000313010318.F10197@ganymede.isdn.uiuc.edu> Bill Wendling (wendling@ganymede.isdn.uiuc.edu) wrote:
> Also sprach Bill Wendling:
> } Sorry if this is completely off topic but...
> }
> } I'm trying to install Linux (RedHat 6.0) on an HP Ventra XU 6/150. When I
> } get past the BIOS starting stuff, it stalls only printing LI on the
> } screen. I've run lilo a number of times and it seems to get the correct
> } lilo.conf file (lilo, version 0.21). I've checked the FAQ in
> } /usr/doc/FAQ, it says that I might have to place the whole root directory
> } within the first 1023 cylinders. The / directory is on a 100M partition
> } and the whole disk is only 1G. The disk is SCSI. I've updated lilo to the
> } newest one RedHat seems to have and it didn't help.
> }
> } Any clues?
> }
> Discovered the problem. Apparently, the machine was shipped with SCSI
> set to allow DOS to access disk drives > 1GB in area. This had to be
> disabled in the SCSI configuration subsection during booting.
This is not true.
> It would seem as if this is a potentially big problem. I didn't find it
> in the docs. I hope to have more information on it so that I could write
> something up, maybe...
Ok. I'm not know if it's in FAQ somewhere or not but it's common truth: there
are NO way to reliable detect BIOS's imagination about disk geometry (even
asking BIOS is not reliable way: sometimes BIOS will tell you one thing and
then will use other value internally; I've seen such pathological BIOS'es;
in such case even DOS can not be setuped easily; thnx God such cases are rare).
Since both IDE and SCSI disks DO NOT have any geometry (Ok there are exist some
complex internal geometry; it's not even exported to interface level so
forget about it). So BIOS doing something out of "plain array of blocks" to
make INT13 usable. Said geometry is needed in two cases:
1. To load linux kernel -- till linux kernel and proper driver is activated
the only way to access disk is via INT13
2. To find out where partitions on disk placed.
If there are exist partition table on disk kernel will use geometry stored in
partition table (so 2. will be easy to do). If there are no partition table on
disk kernel will try to cook up some geometry (you can ask IDE and parhaps SCSI
(not sure here) disks about "preferred geometry" but then neither Linux kernel
not BIOS is forced to use that geometry) and it's quite common to get other
geometry then BIOS cooked up for itself. Then kernel will use this "wrong"
geometry in fdisking and later in LiLo. So system will not boot. There are two
fixes possible:
1. to use DOS'S fdisk and
2. to use LiLo commands to fix LiLo's imagination about geometry
Of course still other fix possible: you can alter BIOS and change its
imagination. This is what you done.
P.S. This is all stupid and unneeded :-(( But it's how PC hardware is built :-/
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This archive was generated by hypermail 2b29 : Wed Mar 15 2000 - 21:00:24 EST