RL02 version of UNIX6?

Guy Sotomayor Jr ggs at shiresoft.com
Thu Feb 2 13:55:29 CST 2017

> On Feb 2, 2017, at 11:38 AM, william degnan <billdegnan at gmail.com> wrote:
>> On 2/2/17 11:32 AM, william degnan wrote:
>>> All this talk about compatibility...was there ever UNIX made for the PDP
>>> 11/40 and RL02, or was it only run on RK05?  Wouldn't all of the C and
>> wake
>>> calls, etc issues have been solved then?  Why is this an issue now?  I am
>>> largely ignorant to the details but from 20000 feet it would seem like
>> this
>>> would have been taken care of long ago.  No need for pre-processing code,
>>> etc.  Please educate me if I am wrong, just curious.
>>> Bill Degnan
> On Thu, Feb 2, 2017 at 2:36 PM, Al Kossow <aek at bitsavers.org> wrote:
>> DEC V7m comes to mind.
> Yes, but in 1974 that was not an option. I guess the 74-77 version of UNIX
> that would have been installed on a PDP 11/40 would have been made for RK05
> drives.  It would prob be worth the effort to find a version of UNIX 6 for
> that media and port to RL02, rather than take a vanilla UNIX 6 and try to
> make it work on RL02's and re-solve all of the problems that have already
> been solved for the RK05 version.  AND the RL02 is larger so moving a
> multi-disk UNIX for RK05 disks/partition would  not be confined by space.

My first exposure to Unix was in 1977.  We were running v6 on a *new*
PDP-11/34 with 4 RK05 drives.  At time time DZ11’s were in short supply so
we (my room mate and I) built a z80 terminal concentrator so that we could
run 16 terminals off of the 11/34.  I wrote the code on the z80 and he wrote
the Unix driver.  We ended up re-working the protocol several times because
we kept loosing control packets.  It wasn’t until later that we discovered that
the DL11 were were using to communicate with the z80 would not stay in
8-bit mode…we replaced the DL11 and everything was solid.

TTFN - Guy

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