PDP-11 disk image question

Glen Slick glen.slick at gmail.com
Tue Feb 19 15:14:04 CST 2019

On Tue, Feb 19, 2019 at 11:22 AM Bill Gunshannon via cctalk
<cctalk at classiccmp.org> wrote:
> > I have mostly used CMD CQD-220/TM controllers. As far as I remember
> > they do not have an RA drive emulation option.
> I have a 220A/TM and it certainly does.  Pages 4-10 thru 4-15
> of the manual, particularly Configuration Options "A" and "1".

> Not familiar with the 220A/E it's not mentioned in my manual.
> Probably a much newer version.

What version of the CQD-220A manual do you have? Do you only have a
hard copy, or do you have a scan of the manual? If you have a scan of
the manual it would be great to get a copy of it. Currently there
isn't any version of a CQD-220A manual on Bitsavers. I have a scan of
the MAN-00220A-000, Rev. 1.1, December 17, 1993 version of the
CQD-220A/223A manual. The RA drive emulation option must be newer than
1993 as I don't see it in the version of the manual I have.

Also, there are two main versions of the CQD-220, the original
CQD-220, and the newer redesigned CQD-220A version. The 'A' suffix is
an important difference. Each main version has minor versions, which
are are PAL and firmware differences.

The original CQD-220 has 220/M (MSCP only), 220/T (TMSCP only), and
220/TM (both MSCP and TMSCP at the same time) versions. The 220/M and
220/T versions can be converted into a 220/TM version by replacing the
CSR decode PAL and the firmware EPROMs. I know this can be done
because I have done it several times myself. This original version is
all through hole, except for the 53C90A SCSI controller in a PLCC
package. The firmware is contained in two 27C256 EPROMs.

The newer CQD-220A has 220A/TM (both MSCP and TMSCP at the same time)
and 220A/M/T (either MSCP or TMSCP, but not both at the same time)
versions. The boards that I have with CQD-220A/E stickers on them must
be the same thing as a CQD-220A/M/T. This newer redesigned version is
roughly half through hole, and half surface mount, including a large
CMD ASIC. The firmware is contained in two 27C512 EPROMs.

I just looked at the CQD-220/TM firmware images that I have. I must
have the B2A 06/24/94 version installed on my boards. In that version
I don't see any RA strings in the firmware image. In the B3 09/23/94
version I do see RA strings.

CQD-220/TM B3 Firmware 09/23/94:

"List of all supported device media type
0. Default value
1. RA 70
2. RA 80
3. RA 81
4. RA 82
5. RA 90
6. RA 92
7. RC 25"

I'll have to try the B3 Firmware 09/23/94 version on my CQD-220/TM boards.

Anyway, I'll still try to find time to see exactly what MSCP drive
geometry a CQD-220A reports when configured for RA drive emulation.

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