3B2 Drives

[Eric J. Nihill]

 There has been a few questions about Configuration of Drives
for a 3B2/300-310-400, so here is a summary of the information
that I have to date:

Type			Configuration Variable		
	Drive	# of 		# of tracks	# of sectors	# of bytes
	ID	cylinders	/cylinder	/track		/sector

CDC
WREN	3	697		5		18		512

Seagate
10 MB	2	306		4		18		512

CDC
WRENII	5	929		9		18		512

Fujitsu
72 MB	8	754		11		18		512

Mini-
Scribe
6085	4	940		8		18		512

Maxtor
XT-1140 9	918/1024	9		17		512

For more info on using a MAXTOR:
->From: woods at eci386.uucp (Greg A. Woods)
->Subject: Re: 3B2 Drives
->The 1140's should be 15 heads, 17 sectors/track, 512 bytes/sector, and
->918 cylinders.  You can format most 1140's to 1024 cylinders.
->Some people say that you can run them right out to 1224 cyl., as long
->as you aren't booting off them.  I never tried it.

(and)
->
->From: woods%eci386 at uunet.UU.NET (Greg A. Woods)
->Subject: Re: Maxtor Drives
->
->[ On Tue Nov 20 12:37 (Re: "Maxtor Drives"), you wrote: ]
->>   It seems that there is a hardware configuration problem
->> between a 3B2 and a XT series Maxtor. This problem of being
->> able to read the defect table one minute and not the next
->> seems to be common with several XT series Maxtors on several
->> 3B2's. 
->Nope, it's a driver bug.
->>   Are there any options on the drive that should be set to
->> make it work with the 3B2? Jumper pins? Cut traces??
->Yup, there's a patch (sorry I don't have the actual patch, since my
->machine is down and out [lightning strike], but you should be able to
->get the fix from AT&T).
->I found this patch did not fully correct the problem, but only reduce
->the hangs to a very short (1-5 secs.) time.  The drive(s) will always
->re-cal. though, and yes if you get a bad-block when this happens, it
->can start thrashing.
->The only real fix would be to re-write the id interrupt handler, and
->or speed up the machine.
->
->Here's the readme3b2/3.1/README.id_hang:
->Some 3B2's with two integral disk drives occasionally "hang" for anywhere
->between 10 seconds and a few hours.  Then, for no obvious reason, the hang
->will clear itself up.
->Closer inspection reveals that processes are hung on one of the integral
->disk drives, usually the second one.  Not all processes are hung,
->though it usually seems like it to the users.
->A patch to the integral disk driver accompanies this README.
->This is the second published patch for this problem.
->The original patch would not eliminate the hangs entirely, but would
->reduce their duration to at most 20 seconds.
->THIS patch prevents the hangs entirely.
->This patch is for UNIX System V Release 3.1 on a 3B2.
->It includes one file besides the README.
->$ ls -l
->-rwxrwxr-x   1 rbc      ucs        36248 Oct 27 17:21 idisk.o
->$ sum -r idisk.o
->05778    71 idisk.o
->To install:
->Login as root.
->Save a copy of the original driver and /unix (Hopefully you have room):
->	# mv /boot/IDISK /
->	# cp /unix /unix.old
->Note: Do NOT save a copy of IDISK under a different name in the /boot directory!
->Use mkboot to format the idisk.o file into the /boot directory.
->	# mkboot idisk.o
->Reboot the system in a way to make a new /unix.
->	# touch /etc/system
->	# shutdown -g0 -i6 -y
->
->That should do it.  To monitor use:
-> # /etc/crash
-> > od idscancnt 2
-> 40253824: 00000002 00000001
->                  ^--------^- This shows 2 resets on drive 0 and 1 reset
->                              on drive 1.  If no patch is in, idscancnt
->			      will not exist.  If the old patch is in,
->			      these numbers show the number of hangs
->			      that were noticed and reset within 20
->			      seconds.  If this (the new) patch is in,
->			      these numbers should always be 0 unless
->			      there is a hardware problem.

I called AT&T, but their tech support was not quite sure what
I was referring to about a patch, then told me I should not 
need it since I was using R3.2.

Hope this info helps. Feel free to add to it and repost additional
information.
					Eric
-- 
     Some do, some don't.           |       eric at sactoh0.SAC.CA.US
    Some will, some won't.          |      ames!pacbell!sactoh0!eric
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