Fujitsu 2361's, SC7003's, 4.3BSD

[Chris Torek]

In article <1305 at cit-vax.Caltech.Edu> mangler at cit-vax.Caltech.Edu
(System Mangler) writes:
>... hpmaptype() is trying to key off of the drive type to see if
>it's "safe" to poke the holding register.  I think this isn't necessary.

If anyone knows otherwise, let us know.  I was just bitten by this.
We put a fifth Eagle drive on an SC788 controller, and could not
get drive four to show up as an Eagle.  Switching the drive numbers
on 3 and 4 showed that the drive itself was configured properly.
It turned out that the last person to fool with the 788 configuration
had left the switches in `4 RM02, 4 RM05' mode, instead of `8 RM02'
mode.  I would rather have the software figure out the hardware
configuration in spite of the switch settings.

>The sector search "optimization" code, which is even more wrong in
>4.3bsd, will degrade throughput when several drives are active on
>one controller. ...  Making it work correctly would require more
>cooperation between the hp driver and the mba code, and isn't worth it.

Why not?
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)
UUCP:	seismo!mimsy!chris	ARPA/CSNet:	chris at mimsy.umd.edu