29 May
2013
29 May
'13
10:10 a.m.
One area where people get burnt with TU58 (real) is that when it sends
data the receiving system better be able to keep up for the whole packet!
That sometimes means the data rate must be lowered from 38,400 to
whatever works for the system in question. For example PDP-11/44s
had problems using the console port at more than 9600!
Allison
On 05/29/2013 11:33 AM, Brian L. Stuart wrote:
My first
reaction is that the most likely problem is the
RT-11 image on the emulated TU-58.
Thanks for the suggestions. As an update,
I've done
a little more investigating. I ended up installing
tu58em and verifying that the tape image was good
and that I could boot using tu58em. Last night, I
did a dump of tu58em's debugging output and manually
issued the same set of reads to my emulator. I verified
that all the packets had the same checksums, the same
first few and last few data bytes, and that the end
packets all matched. So it's looking like it's coming
down to either something related to timing or there's
something I'm not doing right with respect to breaks
or inits. In looking over the RT-11 boot code, I'm
now pretty sure that things break down when it shifts
from using the boot version of read to the read interface
the monitor uses. I"m thinking my next step is to interpose
a machine with 2 serial ports and record the whole protocol
when it fails and see if that shows anything.
BLS