Data Systems Design DSD-880 8" floppy and hard drive?

From: Bob Shannon <bshannon_at_tiac.net>
Date: Wed Jul 23 17:39:01 2003

Jerome H. Fine wrote:

>>Bob Shannon wrote:
>>
>
>>The DSD boxes I used do not emulate DEC drives, and made the 45 meg hard
>>drive
>>available as a single device.
>>
>
>Jerome Fine replies:
>
>As far as I know, the DSD 880/8 and the DSD 880/30 all used
>only a Qbus controller. And they accepted the standard DEC
>device drivers in RT-11.
>
Oh no, there is a unibus DSD controller, I'm absolutley positive about
this. I've owned two, and serviced
a great many back in the Eli Heffron days.

>
>
>There may have been other DSD boxes in addition the the DSD 880
>and DSD 440, but I had not heard about them, let alone the details.
>
>>I have, err, well, Jay West has a DSD floppy-only (RX-02) emulation in
>>his 11/34a out
>>in my garage, and that does use the standard driver.
>>
>
>That was the DSD 440 which emulated the RX02. For this drive,
>I used BOTH a Unibus controller on a PDP-11/34 and a Qbus
>controller on an LSI-11 within a VT103. What I found MOST
>amazing at the time (1979) was that the same RX02 floppy would
>BOOT on BOTH the Unibus and the Qbus systems even though
>the hardware was so different - especially the CPUs. RT-11
>was able to self-configure on the fly to whichever hardware was
>present during the boot phase.
>
>>I guess DSD had many varients, and we must be talking about different
>>products.
>>
>
>Seems like it. BUT the header stated DSD 880, so I went along
>with it. Any idea what the actual hardware was?
>
>>But the unibus version of the DSD interface for the floppy-hard drive
>>combo's I've
>>worked with all needed a DSD driver for RT-11.
>>
>
>Again, was that a DSD 880/8? If so, DSD did provide a driver
>for the RL02 interface which normally used 10 MBytes to allow
>for the 8 MByte hard drive. I don't feel that this was a special
>DSD driver that was essential since the standard DL(X).SYS
>could be used with the DSD 880/8 to give a 5 MByte usage
>of the hard drive as an RL01 drive. That meant that 3 MBytes
>were lost to the user, but it would still work with the standard
>distributed DEC RT-11 device driver.
>
>Sincerely yours,
>
>Jerome Fine
>
All my DSD experiance is unibus based. Qbus machines have no
blinkenlights, and are in my eyes,
unworthy.
Received on Wed Jul 23 2003 - 17:39:01 BST