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<p>I am trying to remember the lights on the 11's that I used; these
are in the 1978-1981 time frame. WPI had an 11/45 with a (NICE!)
GT40 in mechanical engineering which ran RT-11. I remember that
busy looping. The computer science department had a (mighty)
11/05 which ran a couple of things:</p>
<ul>
<li>RT, looping (lots of blinky)</li>
<li>Unix, can't remember as we almost never ran it. It was pretty
much a curiosity and the terminal handling of the time was
thoroughly despised.</li>
<li>RSX, not so much blinky</li>
</ul>
<p>Columbia had a very nice 11/45 which ran RSTS which didn't blink
so much. 11/40's (which were the front-end's for the 20's) ran a
version of RSX called 20F (Johnny can speak to it better than I
can). For Tops-20 3A, it didn't have much to do as the DH's
handled a bit of the buffering, so it didn't blink so much. From
version 4 on, it had to handle smooth scrolling which broke
everything; it had to do continuous polling to looking for ^S's,
which the hardware would not pause on. Lots of blinky, which was
a shame because you used to be able to open the door and could
guess at how many users you had by looking at the lights for 3A.</p>
<p>The DN20's ran either MCB (DECnet) or DN60 (IBM bisynch
communications). However, these were 11/34's which couldn't even
do blinky. I don't know how MCB idle's; I don't think we had
source.</p>
<p>We did have source for the DN60, which I was responsible for
being the Galaxy dude. The DN60 appears to be written from
scratch, but some of it strikes me as possibly being from RSX. It
had a three level 'friendly' round-robin scheduler (I.E., no
preemption). Basically, the idle task either updates various
clocks, checking for certain conditions or it loops checking to
see if any tasks can be run. I would predict that, were it to be
run on something with a bit display, that there would be a lot of
blinky.<br>
</p>
<div class="moz-cite-prefix"><font size="+1"><tt>;</tt><tt><br>
</tt><tt>; SUBROUTINE CALLED BY THE DISPATCHER WHEN ALL TASKS
ARE WAITING.</tt><tt><br>
</tt><tt>;</tt><tt><br>
</tt><tt>DSPIDL: INC DSPMTY ;NOTE DISPATCHER IDLE
CYCLE</tt><tt><br>
</tt><tt> BVC 11$ ;BRANCH IF NO OVERFLOW</tt><tt><br>
</tt><tt> STOPCD WDG ;CLOCK HAS STOPPED
TICKING</tt><tt><br>
</tt><tt>11$: CMP DSPCLK,JIFCLK ;IS THE DISPATCHER
CLOCK UP TO DATE?</tt><tt><br>
</tt><tt> BNE 12$ ;NO.</tt><tt><br>
</tt><tt> RTS PC ;YES, CHECK ALL TASKS
AGAIN.</tt></font><br>
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<div class="moz-cite-prefix"><br>
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<div class="moz-cite-prefix">Those quotes are great; I don't
remember anything like that in DN60.<br>
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<pre class="moz-quote-pre" wrap="">On 10/1/21 9:00 PM, Paul Koning wrote:
That's what I thought but that's only half correct. RT-11 SJ does busy looping; RT-11 FB has an idle task that includes a wait instruction (which is how it gets the rotating lights pattern -- the difference with other OSs is that it sets the pattern into the display register rather than into R0).
; "A SOURCE OF INNOCENT MERRIMENT!"
; - W.S. GILBERT, "MIKADO"
; "DID NOTHING IN PARTICULAR, AND DID IT VERY WELL"
; - W.S. GILBERT, "IOLANTHE"
; "TO BE IDLE IS THE ULTIMATE PURPOSE OF THE BUSY"
; - SAMUEL JOHNSON, "THE IDLER"
10$: DEC (PC)+ ;THE RT-11 LIGHTS ROUTINE!
20$: 1
BNE 14$ ;NOT TOO OFTEN
ADD #512.,20$ ;RESET COUNT, CLEAR CARRY
16$: ROL 13$ ;JUGGLE THE LIGHTS
BNE 11$ ;NOT CLEAR YET
COM 13$ ;TURN ON LIGHTS, SET CARRY
11$: BCC 12$ ;NOTHING FELL OFF, KEEP MOVING
ADD #100,16$ ;REVERSE DIRECTION
BIC #200,16$ ;ROL/ROR FLIP
12$: MOV (PC)+,@(PC)+ ;PUT IN LIGHTS
13$: .WORD 0,SR
14$: MOVB #MXJNUM/2+200,INTACT ;DO A COMPLETE SCAN
EXUSLK: BR EXUSER ;BACK INTO LOOKFOR LOOP
paul
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<pre class="moz-quote-pre" wrap="">On Oct 1, 2021, at 8:54 PM, Johnny Billquist <a class="moz-txt-link-rfc2396E" href="mailto:bqt@softjar.se"><bqt@softjar.se></a> wrote:
<pre class="moz-quote-pre" wrap="">Also for RSX. Basically, they both use WAIT, and that's all that is required from simh. RT-11 is busy-looping, though.
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<pre class="moz-quote-pre" wrap=""><pre class="moz-quote-pre" wrap="">On 21-Oct-01 15:25, Paul Koning wrote:
Yes for RSTS, I don't remember RSX, and I don't think so for RT11.</pre></pre>
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<pre class="moz-quote-pre" wrap="">On Oct 1, 2021, at 4:00 AM, Brian Hechinger <a class="moz-txt-link-rfc2396E" href="mailto:wonko@4amlunch.net"><wonko@4amlunch.net></a> wrote:
Man I wish we weren't on the Amber list. Such a hassle to travel there right now.
I should get simh fired up on the NUC. I'm thinking something PDP-11 and then maybe..... RSX? I don't even know what I'd want to run.
Does the PDP-11 stuff properly do idle? The NUC is pretty powerful, why not run several PDP-11s? :-D
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