Date: Fri, 2 Jun 1995 09:01:18 -0600 From: aflundi@sandia.gov (Alan F Lundin) To: hackers@freebsd.org Subject: FreeBSD 2.0.5-Alpha Installation Message-ID: <199506021501.JAA24405@sargon.mdl.sandia.gov>
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First of all many thanks to the core team for all the wonderful ideas and software they've producted. I haven't managed to get 2.0.5A up yet, but I'm sure it's just because I'm being stupid or haven't read all the right things. I really don't understand the relevant details to the new slicing (how much pad goes up front, how much behind, what types/flags, etc), but I expect that'll be resolved soon with the "slices" document. The real "problem" (which I could ignore, like I've done for the past 2 years) is that I have a Fujitsu SCSI M2624SA 520.1M (formatted) disk, but only 507M are being used because of a conservative geometry read in (from the disk?) by the installation program. That's about 13M that's being wasted and it seems like I ought to have a way to reclaim it, especially since I don't used DOS and hence don't need to play silly DOS/BIOS games. (I've noticed for years that third party vendors pre-format or pre-label or document cyl/hd/sec values that similarly waste large amounts of space, and I've found it worthwhile for the disks I used on the Sun hardware here to find better values). In the install program (which is really neat work BTW) I've tried to adjust the geometry using the G command. It updates the geometry at the top of the screen, but doesn't seem to re-calulate the total number of sectors, so changing the geometry doesn't seem to really do anything useful for me (at least I don't see a way to use it). I tried the Wizard mode, and fed it a "phys ## ## ##" command which seemed to be a step in the right direction, but I couldn't figure out what to do next (slice ignorance as well as Wizard mode ignorance). Just to make this problem a little harder, my documentation for the SCSI disk drive does not reveal how many sectors are available (Fujitsu appears to have taken seriously the convention of manufacturers not giving users all the information they need to know!). Which brings to mind an idea. How hard would it be to add a probe command to the install program that would take a user provided absolute sector number (or a cyl/hd/sec number set), read that sector and return a read success or failure status. That way a user could discover how big their disk really is, then from that fake up some cyl/hd/sec values to get as close as possible to that max abs sector value. (It surely would be nice to throw out this geometry non-sense and just deal in sectors for SCSI disks!). Anyway, in summary, is there a way to change the disk geometry values that then uses a new abs. sector count based on that geometry (I'm interested in a FreeBSD-only disk, but perhaps others are also interest in mixed DOS/FreeBSD/??? disk), and is there an easy way to do a probe a SCSI disk to find the real total number of sectors (as opposed to reading the bogus DOS'ified cyl/hd/sec values from the SCSI label)? Again, many thanks for a great job. --alan
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