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PDP-11 and Funny Facts

Hunta

Experienced Member
Joined
Mar 23, 2021
Messages
459
Location
Samara, Russian Federation
Code:
The PDP-11 is DEC's first and only 16-bit processor.

It was perfect right away :)

From DOS-11 V004A documentation:

Code:
If CTRL/C is typed immediately following the RETURN key, the Monitor will echo the ^C and hang
- a Monitor restart is required. A very slight hesitation (blink your eyes) after typing the RETURN key
is all that is necessary to circumvent this problem.

No, turning it off and on was not the FIRST way to solve problems on computers. The first was - blink-blink.

From RT-11 v5.7 source distribution kit:

Code:
...
SST   .SAV  186. 1977-03-31
RT11SR.SYS   97. 1997-02-29
VD    .MAC    1. 1995-05-06
...
IDCND .MAC    1. 1995-05-06
SBROL .CND    2. 1997-02-29
SBROL .ANS    6. 1997-02-29
SBROL .BLD    1. 1997-02-29
SBROL .MON    3. 1997-02-29
SBROL .DEV    2. 1997-02-29
SBROL .TBL    4. 1997-02-29
TIM   .COM    1. 1997-11-27
...

From SBROL.ANS

Code:
; SYSGEN V05.14001 Answer File Created  29-Feb-97  00:32:37
;
; THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY ONLY  BE  USED
; OR COPIED IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE.
;
; COPYRIGHT 1989, 1990, 1991, 1992 BY DIGITAL EQUIPMENT CORPORATION.
; ALL RIGHTS RESERVED.
;
...

Code:
There is no reason anyone would want a computer in their home.
Ken Olsen, President, Chairman and founder of Digital, 1977

RSX-11M-Plus stack:

Code:
;
; EXECUTIVE STACK AREA
;
        .ASCII  /COPR. (C) MENTEC  1995/ ;ASCII COPYRIGHT NOTICE

        .ASCIZ  /*PDP-11 25TH ANNIVERSARY*/

        .ASCIZ  /*RSX-11 20TH ANNIVERSARY*/

RMON comments:

Code:
; "GORT, Klaatu...borada...nikto"
; - "Day the Earth Stood Still"
;
; "The death of God left the angels in a strange position."
; - Barthelme, "On Angels"
;
; "I could prove God statistically."
; - George Gallop

From RSX-11M-Plus

Code:
;+
; **-$CKINT-CLOCK INTERRUPT
;
.....
;+
;  If we cannot process a clock interrupt within 10 seconds, we are
;       no longer processing in real time, and we may as well become
;       a VAX ... Call an end to this ... NOW!
;-
        BGCK$A  BF.SAN,BE.IDC,<FATAL>   ;;; System massively confused

From memo:

Code:
BLUEFISH represents the new high end of the PDP-11 architecture offering performance in excess of
the 11/74 (target at 1.5 times 11/74 base processor) at a significantly reduced cost (0.5 transfer cost
of 11/74).
...
Upon execution, the MFPT instruction returns to the low byte of R0 a processor model code
(octal 3 for PDP 11/68). The high byte of R0 will be loaded with a processor specified subcode
(octal 0 for PDP 11/68.

From RSTS/E history

Code:
...

1994

New DECtape 4, based on optical paper tape reader that senses round holes punched in the tape,
now able to back up an entire 2 inch RA95 disk (1792 megabytes) in less than 20 miles.

...

1995

New PDP-11 processor, capable of running in compatibility mode, includes a subset of
VAX machine code instructions within the user programmable microcode.

...

1996

RSTS Version 14 supported new PDP-11/800 series systems, which are based on GaAs
(Gallium Arsenide) G-11 processor. Benchmarks show that the new CPUs run at 4.5 times
the speed of PDP-11/70 and feature a new 24 bit memory management unit:

11/20                      16  bits     64 Kb
11/40                      18   "       256 Kb
11/70                      22   "       4 Mb
11/810                     24   "       16 Mb

PDP-800 series regarded as simple "upgrade" for VAX 9000 users.

...

1998

First prototypes of video phones based on PDP-11 (using new K-11 chips) now available
at less than $100. This unit also incorporated both speech and fax circuits.

...

2005

FINS-11, special military version of the PDP-11 developed for US Navy. It features both
TUNABUS and OCTOBUS for high speed transfers, DECwet/E for communication via micro-fiche
and, of course, a CORAL compiler. The whole system is mounted on special ten legged
DECapod chassis.

...

2027

First computer 100% designed and built by a PDP-11 artificial intelligence system resembles
an early 11/45, complete with a FASTER-BUS and a CHEAPERNET.

...

2031

Robinsons Ripples allow the polarising of radio frequencies to be both multiplexed and magnetised
in smaller waves (Ripples) which transmits data at 8 times the speed of light.

Vapournet becomes trade mark of Digital Press Office.

...

2048

New PDP-11/900 series announced with 32 bit memory management unit. Range now comprises of:

PDP-11/924 Unibus Entry model-being discontinued
PDP-11/944 Unibus Mid range
PDP-11/928 Top of the range
PDP-11/911 Fastest PDP-11 ever built

LONG LIVE THE PDP-11!"
 
Last edited:
I love some of the comments in code

Wasn't there some Tolkein in a DEC OS ?

In one of our source code listings for a bit of the Reactor control code there is a rant from one of the programmers about how some essential information on how an instruction actually works was missing from the programming manual :)
 
A comment seen in some simulator code: The documentation for this code was last seen in Lord Lucan's hand luggage.

Dave
 
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