25 May
2011
25 May
'11
7:38 p.m.
Dave McGuire wrote:
On 5/25/11 9:34
AM, Jerome H. Fine wrote:
Nah, I
don't really dislike RT11. I'm just accustomed to
multitasking/timesharing operating systems. (beyond RT11FB, you know
what I mean..)
You are either unaware of Multi-User Basic under RT-11
or you may have not remembered. While RT-11 has no
file sharing capability and is certainly slow when run
on a PDP-11/23 and limited in the size of files when
only an RK05 is available, Multi-User Basic was
available even before 1980 under RT-11. The Chicago
Tribune required a system to handle
their multi-million dollar newspaper printing presses.
...
...
All this was done in 1981 with V04.00 of RT-11
with
just 256 KB of physical memory.
That's a fantastic story, thanks for typing it up! I was unaware of
the history of MU-Basic. Those guys did some really impressive things
with it. In addition,
while I agree that for a multi-user environment,
scheduling a job based on its priority is essential, I have
6 VT100 terminals on my desk for the real PDP-11.
System jobs are used to run 5 of the VT100 terminals
in EDIT mode so that I can look at sufficient portions
of the listing files which are produced by MACRO-11
along with having enough of the program listing displayed
when I am debugging the program under SDX.SYS
which freezes the complete system when stopped at
a break point. While a bit inconvenient, it was not
so difficult that switching to TSX-Plus was worth
while to allow access to different parts of the listing
as I progressed through the program. So, again,
within a single user situation, RT-11 does easily
support multiple jobs or multi-tasking, especially
so under RT11XM with multi-terminal support.
While I hadn't forgotten about MU-Basic, I HAD forgotten about
multi-terminal support under XM. I've never actually used it. I will
fire up simh and give it a run sometime soon. One question: How does it handle user authentication
and access
control?
Very well. A "User Id" and "Password" file that can be
managed by the SYSADMIN. I don't have the manuals
handy, so no details.
I hope that my
example of how I use RT-11 has
convinced you that RT-11 (within the limitations
due to the scheduling algorithm) is just as much
of a "multitasking/timesharing" system as RSX-11
and RSTS/E. I often set the background task to
execute a command file which assembles and links
the current program beng developed WHILE I use
the system EDIT jobs to look at the listing of the
program, especially when the program has many
subroutines and many assemblies combined into
one program at the end.
It certainly can be, yes. Note well that I'm not really dissing
RT-11; I hope you don't take my comments that way. I use it when I
feel it's appropriate. I've always found it odd that DEC added two
different ways of achieving multi-user operation to a single-user OS
when systems like RSX existed. It has always seemed a bit kludgy to
me, and it paints RT-11 in a bad light by seemingly making it "play
catch-up" with the OSs of the time which were designed for
multiuser/multitasking operation in the first place.