Subject: Re: sysinstall "local" tarball
To: None <rvb@sicily.odyssey.cs.cmu.edu>
From: Charles M. Hannum <root@ihack.net>
List: tech-install
Date: 09/18/1998 19:53:00
Um, before you folks go off and implement something weird, let me
introduce some reality here:
1) ATA-4 IS NOT A STANDARD. There is a DRAFT (available from the
usual location on fission.dt.wdc.com in PDF format) but it is NOT a
standard.
2) There are no hard disks which do not support CHS translation. So
for the moment, ignore anything related to such disks.
3) Some of the features you mention (e.g. all of wdp_cur*) do not
exist before ATA-2 or ATA-3, and therefore cannot just be used on
all devices.
4) There is no standard -- or even particularly reliable -- way to
detect what ATA revision a device supports. And please don't start
throwing suggestions at me; I asked on the ATA mailing list and
that was the answer I got. (I did get a suggestion for a klugy
heuristic, though, which I can probably dig up.)
5) Regarding the code I `turned off': it caused a divide-by-0 fault
when accessing a *SCSI* disk with no MBR (which I believe I
documented).
The reason the wd driver always uses LBA mode when available is
precisely to avoid the strange CHS semantics with large disks.