I believe you are correct Tony. It looks like dropping values into
the TMA-11 registers
while the processor is halted does not work.
I had forgotten that I have a 873-YA bootstrap loader installed which
can boot from
a TM11 tape drive. I located a backup tape that was built using
Rollin. I booted
from the tape and I did get the Rollin command prompt
on the console.
So it looks
like the tape drive is in fact working.
You are also correct that if the RK05 works (it does), the grant
signals should be
good up to the RK11 controller.
My PDP-11/05 system with 32kW (28kW usable) now has a working RK05 drive
with RT-11 v2C with MUBASIC and a TMA-11/TS03 tape drive. Once I hook up my
ASR33 teletype, I will have an authentic 1972-ish system. Later, I
will begin work
on my PDP-11/20. That system was installed in Sept/1970.
Many thanks to all who helped sort out my issues.
Sun Aug 7 12:06:09 CDT 2011 Tony Duell wrote:
> To test the tape drive, I used the
programmer's console on my PDP-11/05 to
> issue a read command to a mounted tape. When I issued a read command by
> depositing a command into the TMA-11 command register, the tape advanced
> slightly and then stopped. The 'Bus Grant Late' error was set in the TMA-11
> status register. The status register did indicate the controller and tape drive
> were both ready. No data was read in.
Were you toggling in commands on the front panel with
the CPU halted? I
seem to remmber that some PDP11s will not handle bus requrests / NPRs if
the processor isn't running, and thus if you try to operate such a
peripheral in this wa, you will get a 'late grant' problem. It's better
to enter a short program from the panel and run that. All the program
needs to do is deposit the correct device command word in the right I/O
location (you can set up all the other values -- the address, word count,
etc -- from the panel) and loop either until the device indicates the
command has completed, or just loop forever, and you can halt the program
after a suitable time and examine device registers, memory ,etc.
> The read command was issued while the processor is
> This particular system did not originally have any external devices hooked up
> to it.
> Beginning at the processor, the system has the following components installed:
> KD11-B PDP-11/05
> LS11 line printer card (connects to a Centronics 101A printer)
> MM11-U 16K x 16 core memory
> MM11-U 16K x 16 core memory
> RK11-D RK05 disk controller
> (See http://www.iamvirtual.ca/collection/systems/minis/PDP11-10/Boards.html
> for details)
> The BC11 cable leading to the TMA-11 controller is put on the Unibus
> out connection
> at the last slot of the RK11-D controller.
> Based on previous posts from others, I suspect I don't have the processor grant
> set up correctly.
My first question is 'Does the RK05 work
correctly?'. The RK11-D is an
NPR device too, so if its's working, grants must be getting as far as
that. If the're then not getting to the tape controller, there must be a
fault either in the cable between those devices, or a fault in the RK11-D
itself (I have had a device that failed to pass on a grant, I think one
of the bus driver ICs had fialed. It was an easy fix, anyway...)