Advice on UDA/Eagle problem

[Chris Miller]

This refers to Berkeley 4.2 on a VAX750.

We have a DEC RA81 on a UDA50 as our system disk, and an Eagle on a
controller that emulates a UDA50 as second disk.

We are occasionally getting messages of the following form:
	uda0: hard error
	uda1: hard error, disk transfer error, unit 1, grp 0x300,
		hdr 0x2a6a7, event 0410
	100040 80047e68 d0001 1080002 660001 1020000 0 4800001
		2050000 3000000 1 2a6a7 0 0 0 0 

(I have split lines 2 and 3 for readability).  The apparently spurious
message for uda0 always appears, followed by the two lines for uda1.
The event takes one of the values: 0210 0310 0410
The group can be one of: 0x100 0x200 0x300
The header takes one of the values: 0x2a6a7 0x29724

I cannot work out from the manual or from the "mscp.h" header file
what is happening.  I would assume that one or more bad blocks are
responsible for the Eagle errors, and that the report for uda0 is
caused either by an odd interaction between the controllers or by a
minor bug in the driver code.

Questions:
	Can anyone explain what is happening?
	If it is a bad block, how do I find out which cylinder it is in?
	Can I use the "bad144" program to set up the bad block forwarding,
		and if so, what magic tells it where to put the info
		on the Eagle (the existing code seems to be for an Eagle
		on a Massbus controller)?
	If it isn't a bad block, what is it (or how can I find out)?

Answers by mail please.  If anyone would like a summary of responses,
I will be glad to provide one.
-- 
	Chris Miller, Heriot-Watt University, Edinburgh
	...!ukc!hwcs!chris   chris at hwcs.uucp	chris at cs.hw.ac.uk