LSI-11 Processor Status Word

From: Jerome Fine <jhfine_at_idirect.com>
Date: Fri Jan 22 23:23:33 1999

>Zane H. Healy wrote:

> Stupid question: I'm trying to install TCP/IP on my PDP-11/73 running RT-11
> V5.4 and am trying to choose the proper driver. Does the PDP-11/73 CPU
> have a Processor Status Word?

Jerome Fine replies:

YES!! As Megan Gentry said, all CPUs based on the J11 chip have a
PSW at 177776 within a program and via hardware ODT at:
    777776 on an 18 bit address bus
17777776 on a 22 bit address bus
However, even an LSI-11/02 has a PSW, but you have to use an instruction
(MFPS) to access it and (MTPS) to write to it.
I believe that all Unibus system have a PSW.

There was some mention that the hardware for TCP/IP uses the date as part
of the message (part of ethernet??). Is that true?? And how does that
interact with RT-11 or TSX-PLUS?

Also, do you mean V5.4 "blank" of RT-11 which was released in 1986 or
a later version such as V5.4G which was released in December 1988?

> Also, if you've got a driver for TSX-11 do you have to have corresponding
> driver for RT-11 installed?

If you mean TSX-PLUS, then NO!! Unless of course you also want to us use
the same (hardware - not always) features under RT-11. About the only device
driver which you must have in both RT-11 and TSX-PLUS is the system boot
device since, as far as I know, TSX-PLUS can be booted only as a system
device since the command to boot must be "R TSX", although it is likely that
"RUN SY:TSX.SAV" would also be correct. Note that under V5.4 of RT-11
which are distributed from DEC, if you are on a DU.SYS device driver (you
may boot from RT11FB although RT11SJ is usually recommended), DEC
did not allow you to boot RT-11 from a non-zero partition. There is a patch
to the DU.SYS file which will allow a software boot from a non-zero partition
and thereafter from a non-zero partition for TSX-PLUS.

I won't ask if you want either the RT-11 or the TSX-PLUS to be Y2K compliant.

Sincerely yours,

Jerome Fine
RT-11/TSX-PLUS User/Addict
Received on Fri Jan 22 1999 - 23:23:33 GMT