>Pete Turnbull wrote:
> >On Feb 26, 19:00, Jerome Fine wrote:
> > I seem to remember someone saying that the DSD 440 reads block zero
> > of drive zero on power on, then times out and jumps to location zero
> > to start.
> That's how most 3rd-party RX controllers seem to work, in my experience.
Jerome Fine replies:
It was a surprise to me the first time I read that!
> > Try typing in the MSCP bootstrap.
> Why? The RX02/DSD440 is a DY: device, not DU:
I was just attempting to contrast the size of the hardware bootstrap
program for MSCP with the size for DY. If I remember correctly,
the MSCP version is more than 2 times the size, maybe 3 times the
size of the DY version.
> > The standard RX02 bootstrap uses UNIT=0, so it may need to
> > be modified to use UNIT=1 for DY1:, however that stuff is not
> > accessible to me right now. Does anyone have the release
> > notes for RT-11? It may be there.
> I've had it online for a long time, at
> http://www.dunnington.u-net.com/public/ODT/Listings/RXV21BootD
> I recently made a minor correction (almost all the DEC printed copies have
> several errors). It's a Unit 0 bootstrap, but changing the word at
> locations 001036 from 407 to 427 should make it work for Unit 1. At least,
> I think so; I used it recently and I think that's what I did.
The only 3rd party controllers I have used for the RX02 was the
DSD 440 and the DSD 880/30. I did not realize that
the DSD 440 was like that at the time (over 20 years ago).
The DSD 880/30 does have an actual ROM on the controller that
boots either the DL or the DY.
On rare occasions, I have had to manually enter the MSCP boot
program. Unfortunately, the DEC version allows only DU0: and
partition zero (in RT-11), so it is not really that useful.
And finally, I rarely use the real DEC PDP-11 much these days.
Except for the recovery I am doing to read a dozen RX02 floppies,
I usually run RT-11 software for the PDP-11 under an emulator
on a PC under Windows98 (Yeck). Eventually, there may be
a standalone version of the E11 emulator, but for now, I am
more than satisfied to be running RT-11 code at 20 times the
speed of a PDP-11/73 and have a true RAM: disk of 256 MBytes.
And I can even send an e-mail on the same system.
Received on Wed Feb 27 2002 - 12:36:43 GMT