Quantum Q540 as a RD52

From: CLASSICCMP_at_timaxp.trailing-edge.com <(CLASSICCMP_at_timaxp.trailing-edge.com)>
Date: Mon Sep 21 22:00:46 1998

>Not a silly question in the least. Sort of falls in the "now why didn't I
>think of that" catagory! In all cases except 1 DS1 was jumpered, on the
>one exception, nothing is jumpered. Set it to DS2, no luck, set it to DS3
>and it works. Thanks!

This falls into the category of "my 11/73's line time clock quit
working" :-). *Extremely* common problem, extremely simple answer!

>Next question, does anyone happen to have the list of correct answers to
>give the formating program written down anywhere? Yes, I'm lazy enough not
>to want to have to figure that out.

Roger Ivie posted the following many, many years ago. It's for the RD51,
not the RD52, but it should get you started. One tiny note: Roger
didn't figure out the Media ID scheme, but if you look at the source
code to my DUSTAT utility (i.e. take a look at:
http://sunsite.unc.edu/pub/academic/computer-science/history/pdp-11/rt/dustat/dustat.mac
) and look at my comments there about how the media type code is
represented.

-- 
 Tim Shoppa                        Email: shoppa_at_trailing-edge.com
 Trailing Edge Technology          Voice: 301-767-5917
 7328 Bradley Blvd                 Fax:   301-767-5927
 Bethesda, MD, USA 20817
I've come across the notes I used to format an RD51 (that's a 10MB disk,
folks) on a VS2000. When I was done, I was able to mount the disk under
VMS. Here's what my notes say:
An XBN is a block containing geometry info for the drive.
DBNs are the blocks between the XBN and the end of the cylinder; essentially,
the first cylinder of the drive is reserved to contain geometry info, but
not all of the blocks in the cylinder may be used. DBNs fill out the
first cylinder after all the XBNs are filled in.
LBNs are blocks containing user data.
RBNs are replacement blocks.
RCTSIZ appears to be the size of the replacement block table in blocks, but
I have a ? after my note on that one.
RCTNBR appears to be the number of copies of the RCT on the disk, again I've
makred that with a ?.
Here were my answers to the questions for the RD51. The RD51 has 305 cylinders
and 4 heads. I'm pretty certain the VS2000 and RQDX3 use 17 sectors/track (the
RQDX2 used 18 sectors/track; reformatting a disk with an RQDX3 drops its
capacity slightly):
XBNSIZ: 54      I used 54 because all the info I've seen for other drives
                used 54.
DBNSIZ: 14      A cylinder on the RD51 has 68 blocks. After the 54 XBN
                blocks are allocated, 14 blocks are left in the cylinder.
LBNSIZ: 20000   I just winged this one. You should be able to twiddle this
                up or down by playing with the replacement blocks.
RBNSIZ: 168     I think I picked this because that's what an RD52 uses, but
                I don't remember.
SURPUN: 4       The RD51 has four heads.
CYLPUN: 305     The RD51 has 305 cylinders.
WRTPRC: 305     I don't remember where write precomp is supposed to be turned
                on for the RD51, so I turned it off for the whole drive. This
                should be the cylinder number where write precomp starts.
RCTSIZ: 4       Again, taken from the RD52
RCTNBR: 8       Again, taken from the RD52
SECITL: 1       Sectors should be number 1 through 17 instead of 0 through 16.
STSSKW: 2       Head-to-head skew in sectors. The RD52 also uses 2.
CTCSKW: 14      Cylinder-to-cylinder skew in sectors. I don't remember why I
                picked 14; some experimentation should let you figure out what
                to use here.
MEDIAI: 627327027 I'm pretty sure I looked in the source listings to see what
                the driver was expecting for an RD51. Short of doing that,
                I don't know what else to do here. I don't know if this
                number is really critical for antyhing; the driver should use
                the XBNs to get the geometry information instead of depending
                on the media ID to look it up.

Received on Mon Sep 21 1998 - 22:00:46 BST