Date: Wed, 22 Mar 1995 17:41:06 +1000 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, phk@ref.tfs.com Cc: gibbs@estienne.CS.Berkeley.EDU, gibbs@freefall.cdrom.com, hackers@freefall.cdrom.com, jkh@freefall.cdrom.com, peter@bonkers.taronga.com, rgrimes@gndrsh.aac.dev.com Subject: Re: SVNET Meeting? Message-ID: <199503220741.RAA06611@godzilla.zeta.org.au>
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>The bios geometry is already read in the bootblocks. do a "boot -v" I know about this, but other people may not, and fdisk and sysinstall certainly don't. There is no standard interface to the info, and the programs don't try to read it from kmem. Even if they did, they can't rely on it because old boot loaders and the netboot loader don't initialize it. "boot -v" prints the info in th following human-unreadable form: BIOS geometries: 0:3f63f20 1:3ff3f20 2:4f010f 3:4f010f 4:4f010f 5:4f010f 6:4f010f 7:4f010f 0 accounted for Explanation: BIOS geometries: 0:3f63f20 Hard disk 0 (SCSI but you can't tell). 0x20 heads, 0x3f + 1 sectors, 0x3f6 cylinders. (Actually there are 0x3f7 cylinders. I used to wonder why DOS didn't use the last one.) There should be a newline after the first `:'. 1:3ff3f20 Hard disk 1 (SCSI). 0x20 heads, 0x3f + 1 sectors, 0x3ff cylinders. (Actually there are 4076 cylinders. DOS can't see the cylinders >= 1024 (or even cylinder 1023). The 4076 should be printed by the sd probe so that it gets printed somewhere.) 2:4f010f 3:4f010f 4:4f010f 5:4f010f 6:4f010f 7:4f010f These entries are bogus. They are caused by punting the error handling in the boot. 0 accounted for The sd driver doesn't look at the BIOS geometry so the 2 SCSI drives aren't accounted for. wd drives would be accounted for in rare cases. Bruce
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