Which RT-11 for an 11/03

Jerome H. Fine jhfinedp3k at compsys.to
Fri Mar 11 20:21:46 CST 2016

 >On Thursday, February 10th, 2016 at 12:51:30 - 0500, Richard Cini wrote:

>Is there a listing somewhere of what versions of RT-11 work with which CPUs? The Heath H11 uses the LSI-11 which I think is an 11/03 equivalent. Is there a specific version (or maximum version) designed for this CPU?
>I tried v4 using a method I found on-line (modifying with SIMH to make it bootable as a TU58 image rather than an RK) but it doesn't work so I wanted to first eliminate the system version as the potential problem.
Sorry for the delay in my answer.  I was out of town for the last
36 hours, so I just noticed this thread.

For maximum flexibility, I would suggest V05.03 of RT-11.  It is
just about the most widely available and has the benefit of probably
being completely legal to use on a non-commercial basis with SimH.

V04.00 of RT-11 will probably run equally well, but obviously
without some of the many additional features found in V05.03
of RT-11.  In addition, you might want to check even later
versions of RT-11, all of which still run on a PDP-11/03 CPU.

Under V05.03 of RT-11, you can use either distributed
Unmapped Monitor, RT11SJ or RT11FB.  The size will be
larger than from V04.00 of RT-11, but I suggest that the
additional features are more than worth while.  Since you
have all 32 KW or memory or 64 KB, you will not have
any problem booting RT-11.

If you have any specific questions using Ersatz-11 with
a PDP-11/03, just ask.  That will make sure that the
configuration and the boot device is set up correctly.

Just for practice, you might try using Ersatz-11 with V05.03
of RT-11 with SET  CPU 03.  You will find that Ersatz-11
is trivial to use and that it supports emulation of all types of
disk drives including TU-58, RK05, RL02 and SCSI, named,
respectively, DD:, RK:, DL: and DU:, the same as DEC names
them.  Be warned that after you practice with Ersatz-11, you
may find that an LSI-11, also called a PDP-11/03, is a bit
slower than running with Ersatz-11, even on a 486.  My
experience with just a 750 MHz Pentium III is that RT-11
runs about 15 times as fast as a PDP-11/93.  On a current
I7 from Intel, I expect speeds more than 100 times as fast
as a PDP-11/93.

If you provide some of the information requested below, a
version of RT-11 might be suggested which is a better fit.
Otherwise, my assumption at present is that you want to
use RT-11 since it is the only reasonable choice out of
RT-11, RSX-11 and RSTS/E, although I am reasonably
sure that RSTS/E can't run on a PDP-11/03.  Further, you
want to run RT-11 to be able to show that you can run
RT-11 on the PDP-11/03 hardware that you have.  That
is quite different from the original reason a PDP-11/03
system was purchased, namely to run specific application
programs which were able to run under RT-11.  If I
am incorrect, please let me know and advise otherwise.

It does sound like you have the Heath Kit version of the hardware.
If so, then you probably don't have a hard disk drive.  A complete
list of the actual hardware will be helpful.  In addition, even more
important from my point of view is why you want to use the hardware
that you have to run RT-11 (most likely because it will not run anything
else very easily) and then which specific application programs will be
run after you are successful in getting RT-11 to run.  Just as important
is how you will interface with the PDP-11/03 and move the results
from the PDP-11/03 to either printed output or a system that can
share the results via the internet.

Jerome Fine

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