Re: PDP-11/40 modified to be a PDP-11/23

2016-06-23 Thread COURYHOUSE
now, there is a 11/23 I could love! ---Ed# In a message dated 6/22/2016 9:44:20 P.M. US Mountain Standard Time, glen.sl...@gmail.com writes: BACKPLANE", > so the operation is not so mysterious. I had never seen a hex-wide Q-bus > backplane before this. > > There are some pictures of the s

Re: CDC 6600 - Why so awesome?

2016-06-23 Thread Lionel Johnson
On 23/06/2016 2:38 AM, Brian Walenz wrote: On Wed, Jun 22, 2016 at 12:01 PM, Noel Chiappa wrote: Werner Buchholz (editor), "Planning a Computer System: Project Stretch", McGraw-Hill, New York, 1962 http://ed-thelen.org/comp-hist/IBM-7030-Planning-McJones.pdf Speaking of books

Re: two's complement, was Re: Now OT

2016-06-23 Thread Paul Koning
> On Jun 22, 2016, at 11:05 PM, Swift Griggs wrote: > > ... > Just some internet bungholes on reddit. Brother, just remember, *you* > asked, and you can never get the time back: > > https://www.reddit.com/r/programming/comments/d92jj/why_computers_use_twos_complement_to_represent/ Nice. I ha

Re: CDC 6600 - Why so awesome?

2016-06-23 Thread Toby Thain
On 2016-06-23 3:20 AM, Lionel Johnson wrote: ... I joined CDC in Melbourne, Aust in 1972, worked mostly on 3200 machines - Didn't like the Cybers, but admired the horsepower. I could fix a 3200, every time, that was the best training I ever had, alone with my machine in Hobart, I loved it. When t

Re: two's complement, was Re: Now OT

2016-06-23 Thread Camiel Vanderhoeven
On Thu, Jun 23, 2016 at 4:31 PM, Paul Koning wrote: > > Another interesting aspect where people may not be aware of how much > variety existed is in the encoding of floating point numbers. IEEE > is now the standard, but PDP-11 users will remember the DEC format > which is a bit different. CDC a

Re: two's complement, was Re: Now OT

2016-06-23 Thread Chuck Guzis
On 06/23/2016 07:31 AM, Paul Koning wrote: > I have a copy of 1948 (!) lecture notes on computer design. It > discusses one's complement and two's complement. It points out the > advantage of two's complement (no two zeroes) but also the > disadvantage that negating is harder (requiring two step

Re: two's complement, was Re: Now OT

2016-06-23 Thread Paul Koning
> On Jun 23, 2016, at 10:50 AM, Camiel Vanderhoeven wrote: > > ... > There are many, many varieties of floating point formats. This page > gives a nice overview: http://www.quadibloc.com/comp/cp0201.htm Nice. The CDC 6000 description isn't quite right (or not clear) because a negative float i

Re: two's complement, was Re: Now OT

2016-06-23 Thread Al Kossow
On 6/23/16 8:17 AM, Chuck Guzis wrote: > On 06/23/2016 07:31 AM, Paul Koning wrote: > >> I have a copy of 1948 (!) lecture notes on computer design. It >> discusses one's complement and two's complement. It points out the >> advantage of two's complement (no two zeroes) but also the >> disadva

Re: two's complement, was Re: Now OT

2016-06-23 Thread Paul Koning
> On Jun 23, 2016, at 11:17 AM, Chuck Guzis wrote: > > ... > Of course, there were also machines that used the floating point > facility for all arithmetic. Integer computations is performed as a > subset of floating-point. This has the ramification that an integer > does not occupy an entire

Re: two's complement, was Re: Now OT

2016-06-23 Thread Paul Koning
> On Jun 23, 2016, at 12:07 PM, Al Kossow wrote: > ... > I have also heard that 2s compliment was popular in shorter word length > machines because 1s compliment multiple precision arithmetic is a PITA > to implement. That's true. It certainly can be done and has been. But since one's complemen

Re: two's complement, was Re: Now OT

2016-06-23 Thread Paul Koning
> On Jun 23, 2016, at 12:11 PM, Paul Koning wrote: > > >> On Jun 23, 2016, at 12:07 PM, Al Kossow wrote: >> ... >> I have also heard that 2s compliment was popular in shorter word length >> machines because 1s compliment multiple precision arithmetic is a PITA >> to implement. > > That's true

Re: two's complement, was Re: Now OT

2016-06-23 Thread Chuck Guzis
On 06/23/2016 09:09 AM, Paul Koning wrote: > The CDC 6000 did that in part. It has full 60 bit integer > add/subtract, but multiply and divide are done using the floating > point operations so they work only for numbers up to 47 bits. The CYBER 200/STAR 100 limited integers to 48 (of 64) or 24 (

LINC-8 and PDP-8 manuals

2016-06-23 Thread Mattis Lind
I have been going through our library of documentation and found some items that are duplicates. There are a LINC-8 programming manual, PDP-8 DecTape programming manual, PDP-8/L maintenance manual, PDP-8/e maintenance manual volume I and volume III. http://i.imgur.com/YEAdnZV.jpg?1 http://i.imgur

Re: two's complement, was Re: Now OT

2016-06-23 Thread Lars Brinkhoff
Paul Koning writes: > in the Electrologica machines (Dutch computers from the late 1950s to > mid 1960s), double-length values are encoded with the sign bit > replicated in each word. The PDP-10 double integer format also duplicates the sign bit, but is two's complement.

Forth for RSTS

2016-06-23 Thread Paul Koning
> On Jan 3, 2016, at 4:56 PM, Paul Koning wrote: > > ... > This Forth implementation is a port of Fig-FORTH by John S. James, with some > RSTS-specific magic added. I just realized the file header says that it is > in the public domain, so I suppose I should post the source... Done. Thanks

RE: CDC 6600 - Why so awesome?

2016-06-23 Thread Rich Alderson
From: Swift Griggs Sent: Wednesday, June 22, 2016 6:46 PM >On Wed, 22 Jun 2016, Rich Alderson wrote: >> We have [a DD60] running at LCM, attached to an instance of dtCyber, the >> 6000/Cyber simulator, via John Zabolitzky's Xilinx-based display adapter. >> We're in the process of refurbing the on

Re: LINC-8 and PDP-8 manuals

2016-06-23 Thread Pontus Pihlgren
Hmm, I'm thinking hard of what I should bring on saturday that might interrest you. This is right up my alley. You already have one of each of what I own :D /P On Thu, Jun 23, 2016 at 07:20:13PM +0200, Mattis Lind wrote: > I have been going through our library of documentation and found some it

Re: CDC 6600 - Why so awesome?

2016-06-23 Thread James Vess
Hey guys, I was looking and found that the Tektronix 4010 is a calligraphic display, for which I found a video! https://www.youtube.com/watch?v=IztxeoHhoyM Let me know if it bares a resemblance to the display on the 6600 On Wed, Jun 22, 2016 at 10:32 AM, Swift Griggs wrote: > On Tue, 21 Jun 20

Re: CDC 6600 - Why so awesome?

2016-06-23 Thread Jon Elson
On 06/23/2016 10:28 PM, James Vess wrote: Hey guys, I was looking and found that the Tektronix 4010 is a calligraphic display, for which I found a video! https://www.youtube.com/watch?v=IztxeoHhoyM Let me know if it bares a resemblance to the display on the 6600 It wasn't normally used in tha

Other then being original is there any reason to get a RX02 ?

2016-06-23 Thread Pete Lancashire
Someday I want to have a PDP11 even if it is a QBUS version I can get a clean RX02 for about $150. When my life involved PDP11's starting with 34A and ending with 44's I never used one. -pete

Re: Other then being original is there any reason to get a RX02 ?

2016-06-23 Thread Ethan Dicks
On Thu, Jun 23, 2016 at 1:17 PM, Pete Lancashire wrote: > Someday I want to have a PDP11 even if it is a QBUS version > > I can get a clean RX02 for about $150. When my life involved PDP11's > starting with 34A and ending with 44's I never used one. They are useful on low-end systems, like an RT-