RL02 version of UNIX6?

Mark Matlock mark at matlockfamily.com
Sun Feb 5 15:48:59 CST 2017

>> Bill, Paul,
>>    I have been tinkering with old versions of RSX11M (back to V2) on
>> non-mapped CPUs, primarily PDP-11/05 as I hope to get mine running soon. On
>> Simh
>> with the CPU set as a PDP-11/05 which does not have EIS (I also tried an
>> 11/40 but the SET CPU NOEIS in Simh gave me an error so I couldn't be sure
>> if it was disabled) I was able to boot the baseline distribution for RSX11M
>> V4.0 on a RL02 distribution. See details below on the config I tested.
>> RSX11M is a pretty capable multitasking, multiuser system and would be good
>> fit for the PDP-11/40.
> RL02 or RL01?  I have only RL02 drives (2).  Are you saying you can

   My first PDP-11 system was a PDP-11/24 (256KB) with 2 RL02s. It ran
RSX11M V4.0 and collected RS232 data from lab instruments and
provided a programming environment and handled 3 or 4 users ok. Later
we added a KT24 and went to 512KB. With 2 RL02s one was a system disk
and one was a user/data disk. The utility BRU allowed you to make a copy
of the system disk, but to backup the data disk, one has to boot BRUSYS.SYS
which is a memory resident only RSX11S system that RSX11M includes so
you can remove the system disk and make a disk to disk copy of the non-bootable
user disk. Actually, BRUSYS.SYS is small and you can have the user disk boot block
point to it for convenience.

> 1) Use simH to set up the environment

RSX11M especially in small memory systems should be customized to your hardware.
If you have extra DL or DZ terminal ports or other hardware you will need to do this.
You can use the RL02 disk emulation, but have 4 of them for convenience so you don't
to swap disk images during the process. Once you have SYSGENed an RSX11M system
you are happy with then the RL02 disk image file needs to be transferred to an RL02

> 2) Port to RL02 image disk

This is the tricky part. RSX11M+ can run a TCP/IP stack and the disk image could
be FTPed to it from the Linux or Windows system running Simh. M+ could mount the
disk image file and BRU the image to a physical disk (if the M+ system had an RL02
Drive). I don't have RL02s and don't know anyone who does. Also, you might find
a Baseline RSX11M disk someone has which can be copied and booted.

> 3) Take image put on actual RL02?

Since we are unlikely to find a SYSTEM to do that then, the other way
would be with PDPGUI from Jorge Hoppe. His PDPGUI program can load via ODT
a small driver to write to an RL02 and then transfer a disk image over the console
port. It would take quite a while but it can be done. 


This assumes you have ODT and I don't know if an 11/40 does. The !1/05 
doesn't either but Jorge found that a M9312 bootstrap card with ODT ROMs
will enable ODT on an 11/05 so it should work on an 11/40?


> I agree that it would run on the PDP 11/40 without EIS, but so far I have
> not been able to get it onto an image that will write to actual RL02
> disks.  I was playing around with this yesterday.
> I was also working on getting Fortran onto a RT11 disk and in general
> building a dual drive system that has a programming environment with enough
> space to save program and a dataset.

RT11 would work very well on two RL02s as well. In fact, one can get by with two
RX02s. It is a much simpler operating system.

> I have a lot of RSX11/M manuals and docs here, compared with RT11 I'd love
> to use RSX.  Are tools made for RSX compatible with RT-11, I am reading up
> to see how these compare, what levels they're on...is RT11 like DOS and RSX
> like "Windows" that sits on top of it, etc.  I know RSX is not a GUI, just
> making an analogy.  I am researching all of this, up to this point I had
> only dabbled in RT11.

RT-11 and RSX11M are quite different internally. RT-11 is a single user monitor 
that was extended to multiuser with some later version and via the TSX operating system.
TSX is more like your Windows analogy.

The RSX11M executive was written from the ground up with conditional assembly code that can be
customized for your hardware so any code for hardware not needed can be left out.
When you do a SYSGEN you actually compile the assembly source for much of the
operating system and then link (TasK Build, TKB) it. Utilities come in object libraries and can be modified 
a bit when linking.

Also, many of the features of the OS can be left out if you don't need them. It was designed 
to have executive calls that were compatible with RSX11M and IAS which ran only on large
systems. Much of the same languages can be run on RSX and RT11 (Fortran, Basic, Macro, APL)
and RSX can read RT-11 tapes and disks with the utility FLX.

Good Luck,

> Thanks
> Bill

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