>TRASH3_at_splab.cas.neu.edu wrote:
> The DSD 880 Qbus subsystem used two different cards, the 8832 and the
> 8836. The connector near the handle is 26 pins. For the 8836, the
> 16Mhz crystal is in location G9, with the model number of the board on
> the edge above that, for instance 808836-05 rev K. There are socketed
> 24 pin dips in row e, and headers for programming in D4 and F5.
>
> There isn't really any special software for basic use, but if you want
> the double sided use of the floppies, then you have to either use
> their drivers, or patch your own. The same goes for utilizing more than
> the 2-RL02 emulation feature, you have to patch for more logical units.
Jerome Fine replies:
The V4.00 distribution of the DEC DY.MAC device driver has code
(which is incorrect - I guess that DEC never tested it) for the RX03
floppy which I presume was supposed to be the double-sided RX02.
The code was removed for V5.00 of RT-11. I presume that DEC
had decided at that point to never release an RX03 drive of their
own.
Note that the DSD 880 controller is able to handle ONLY 18 bit
addresses with regard to the DMA silo which is also the problem
with the DEC RX02 drive. It is possible to program a bounce
buffer in RT-11 to get around that problem. I don't know what
other operating systems do to handle that problem.
The RL02 emulation by the DSD 880 does not need a patch as
much as a SYSGEN in RT-11. It the user wishes, the DL(X).SYS
device driver can be SYSGENed to handle up to 4 RL02 drives.
But the distributed DL(X).SYS in all of the RT-11 distributions
will handle only 2 RL02 drives.
Sincerely yours,
Jerome Fine
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Received on Sat Oct 04 2003 - 19:41:03 BST