🚀 go-pugleaf

In article <Added.QXXkSyy00Ui3I9ek9H@andrew.cmu.edu>, OBRIEN%OBRIEN@VENUS.YCC.YALE.EDU ("James A. O'Brien  432-4382", 203) writes:
> I hope someone can help me with this.  I originally had a Seagate ST506
> 5MB drive in my Rainbow - I replaced it with a 20MB ST225 a couple of years
> ago.  My wife has a PC clone and we thought it would be neat to put even
> a 5MB drive in it.  So, I bought a Western Digital disk controller for $70
> mail order, and connected the whole thing up.  I had all the drive parameters
> (153 cylinders, 4 heads, etc) and fed them to the WD formatter (it's in
> BIOS on the WD board accessed through DEBUG).  The drive made clunking and
> stepping noises, which SOUNDED like it was formatting, but it wasn't in
> reality - the program ends with a "nothing done exit".  Now, when I tried
> to run FDISK anyway, I noticed that selecting either fixed disk 1 or fixed
> disk 2 caused my 5MB drive to respond.  My deduction from the above is that
> I need to install some kind of jumper on the drive to perform a correct
> "drive select".  Of course, I have no technical documentation for the ST506!
> 
I'm not sure what your problem is, exactly, but I can make some guesses.

First of all, the ST506 that DEC sold for the Rainbow is for all practical
purposes an unmodified ST506 (they did do a fair amount of culling to get
the best drives in the lot).  And the standard PC interface, at least for
XT-class machines, is an "ST506 interface" - because that was the original
drive to use it!

You shouldn't need to modify any straps or anything on the drive to make it
run on an PC clone.  You will need to get the cables right ... this can be
a bit confusing if you haven't done it much (especially since there are
several different kinds of cable configurations for PC clones, and if you
hook things up the wrong way all sorts of things could go wrong).  Your
problem _sounds_ like a typical cable problem (but may not be ...).

I don't know what Western Digital controller you have.  WD makes a _lot_
of disk controllers and they are not interchangeable!!  Some of them have
all sorts of "features" on them, are combined hard/floppy controllers, RLL
controllers, etc, etc.  Also the BIOS on the controller has gone through
a number of revisions and some of the versions are, of course, better than
others (and the better versions are not always the most recent).  It is
possible that the controller/BIOS you have just can't accept the particular
drive parameters for the 506.

Finally, be aware that the 506 is a much slower drive than the more recent
drives (something like a 95 ms average seek time).  Some controllers/BIOSs
may not like that - and time out on a perfectly valid (and successful)
operation!  It really is critical to know what the controller and BIOS
version are to know if this might be a problem.

Good luck!
						Bruce C. Wright