Looked at the Mentec SPDs right now. While Mentec did some sort of release of
RSTS/E, I can't see anything about the RM06 there, so it seems as if not
supported. The RSX SPD do mention the RM06.
It did require a bit of changes in several places to add the support. But I
would believe it should not be too hard to do on RSTS/E as well, if one have
the sources, time and some knowledge. Before the RM06, RSX also just "knew" the
size of a massbus disk based on the id.
If Rich, or someone else would be interested in adfing support for the RM06 to
that massbus disk emulator just let me know. I'll be happy to help out with
information dug out from the RSX code.
Johnny
Paul Koning <paulkon...@comcast.net> skrev: (11 december 2017 17:44:50 CET)
>
>
>> On Dec 11, 2017, at 11:37 AM, Johnny Billquist <b...@softjar.se>
>wrote:
>>
>> Paul. The RM06 has its own massbus id. The device can also emulate
>existing dec disks, which means no changes needed. But when identified
>as an RM06 it becomes a bit more interesting as this device does not
>have a fixed size. Similar to mscp in that way. It has fixed numbers
>for sectors/track and tracks/cylinder but the number of cylinders
>depends on the actual disk. So the os must figure disk size out at
>runtime.
>>
>> I know rsx does it, as I have the sources. I would expect that Mentec
>also added this for RSTS/E but I have not actually checked that.
>
>I don't know that Mentec did anything to RSTS other than change the
>logo on the cover of the manuals.
>
>RSTS handles non-MSCP disks by determining the drive type, then looking
>up the geometry in a table. So for Massbus, there's a table that lists
>Massbus ID values and the corresponding sector/track/cylinder counts.
>There isn't any support for a given ID having varying size.
>
>It certainly would be possible to write code that pokes at a disk to
>see how big it is, but RSTS doesn't do that. Well, except for the very
>unofficial PRO support I added, which is buried in the V10 code of INIT
>but not otherwise exposed. That distinguishes some PRO disk models by
>doing I/O to check the size, and/or to see how many heads there are.
>But for non-Pro PDP11s, RSTS doesn't do it that way.
>
>Unlike RT or RSX, RSTS was never intended to be customized by users, so
>there is no support for user-written drivers or any easy way to handle
>peripherals not supplied by DEC. It's certainly possible to do the
>work if you have the sources, but neither the process of writing
>drivers not the way to build an OS are documented.
>
> paul
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