COFF December 2024

coff@tuhs.org

7 participants
4 discussions

Re: [TUHS] "Webster's Second on the Head of a Pin"?

by sjenkin＠canb.auug.org.au

Not dissimilar work at AT&T Research ~2000 - compressing fixed-length records, better than gzip, +30% for similar compute time. ‘pzip’ - Adam Bushman & Glen Fowler <https://web.archive.org/web/20041019142227/http://www.research.att.com/~gsf…> Later work by others, building on ‘pzip’ ,claims ‘100x’. > On 30 Dec 2024, at 00:44, Douglas McIlroy <douglas.mcilroy(a)dartmouth.edu> wrote: > > I can supply a copy if no one else has beaten me to it. > > Ron Hardin subsequently pushed the limit even further. Unfortunately, > I do not have a record of that work. > > Doug > > On Sat, Dec 28, 2024 at 9:54 PM Royce Williams <royce(a)techsolvency.com> wrote: >> >> Someone I know is seeking the original version of an internal Bell Labs memo from 1974 titled "Webster's Second on the Head of a Pin" by Morris and Thompson. The topic appears to be related to improving the speed of lookups or search. It's cited in a few papers as "Unpublished Technical Memo, Bell Laboratories, Murray Hill, NJ 1974." All I can find online is citations. Any leads appreciated! >> >> -- >> Royce Other links: This repository included ksh-93 sources Glen Fowlers’ downloads <https://web.archive.org/web/20130514131958/http://www2.research.att.com/~gs…> Later AT&T Research page with Software downloads <https://web.archive.org/web/20090626002505/http://public.research.att.com/i…> THE AT&T AST OPENSOURCE SOFTWARE COLLECTION 2000 <https://www.usenix.org/legacy/publications/library/proceedings/usenix2000/f…> Github Repo for AST - I couldn’t make these compile <https://github.com/att/ast/tree/master> KSH93 <https://github.com/ksh93> -- Steve Jenkin, IT Systems and Design 0412 786 915 (+61 412 786 915) PO Box 38, Kippax ACT 2615, AUSTRALIA mailto:sjenkin@canb.auug.org.au http://members.tip.net.au/~sjenkin

3 months, 1 week

DEC computer Christmas carols

by Paul Winalski

The PDP-10 had an alarm bell that could be rung under program control. When the TOPS-10 operating system crashed, it displayed a numeric code on the console indicating the reason for the crash. This was called a "stopcode" and is the equivalent of a Unix panic. It also rang the alarm bell. DDT (Dynamic Debugging Tool) was the primary debugger for TOPS-10. PPN (Project-Programmer Number) was used for system security. Each user account was assigned by number to a Project, and within that Project a unique Programmer Number. The low numbers (such as [7,3]) were usually privileged accounts. So here we have the Christmas carol Stopcode Bells, to the tune of Jingle Bells: ========== Stopcode bells, stopcode bells, stopcode all the way. Oh what fun it is to crash the system night and day. Stopcode bells, stopcode bells, stopcode all the way. Oh what fun it is to crash the system night and day. Poking through the core With a bug in DDT Change your PPN To [7,3]. Halt somebody's job. Make them scream and shout. Oh what fun it is to log The operator out. ========== This is one that I wrote while I worked in DEC's software development tools department. Around Christmas time the first baselevels of VAX/VMS Version 3.0 were being sent to alpha test. The engineering departments got first crack at the new system and so were the first to encounter bugs and design problems. VMS Version 3 had been a very ambitious project and was eventually split up into Version 3A (released as Version 3.0) and Version 3B (released as Version 4.0). There was a lot of grumbling by groups whose new features got put into 3B and thus delayed. The early baselevels of 3A broke the VAX C runtime library. So here we have Version 3 is Coming to Town: ========== You'd better work hard You'd better code fast. The system you use Just ain't gonna last. Version 3 is coming to town. They fixed some old bugs And put new ones in, Added some features They think will win. Version 3 is coming to town. There's so many new features. Too bad we can't use C. And the things that we most wanted Were deferred until 3B. You'd better work hard You'd better code fast. The system you use Just ain't gonna last. Version 3 is coming to town. ========= -Paul W.

3 months, 3 weeks

Re: [TUHS] After 50 years, what has the Impact of Unix been?

by Douglas McIlroy

Apropos of file types, which Rich Salz commends Unix for discarding. Early in Multics development, I and others visited various influential time-sharing systems in search of good ideas. I tried each one on a simple model of software updating, in particular of remaking a compiler. In every instance I could not make my program work without expert help to get past file-type barriers. My model was based on a trivial Fortran program that copied input to output until an input line with END in column 7 had been processed. Every system was able to compile this program, but ... After compiling, I tried to use the program to make a copy of itself. Here was the first file-type hurdle. Input was typically expected to be of type data, not source code. Gurus had to scramble to overcome this nominal incompatibility. Next I tried to compile the new Fortran program. Same trouble in reverse--data used as source. More scrambling of gurus. Then I ran the newly compiled program to do the above steps over again. This time the gurus had the file-type workarounds under control. One comp center still had trouble, however, which took some time to diagnose. It turned out that Fortran programs were, for unknown reasons, specifically forbidden to read their own source code! One side effect of file-type conventions was that instead of learning once and for all how to create text files, one had to learn different ways to edit files of different types. Doug

4 months

AI and spin locks

by Warren Toomey

I was just trying to find out if there was a way of uploading the TUHS mailing list as a corpus of text into a LLM so that I could ask questions based on the knowledge contained therein. I'm not having much luck yet. Anyway, while messing around with things I asked a simple question and got this answer: What is a spin lock? A spin lock, also known as a spinning lock or spinning lock mechanism, is a type of mechanical locking device used to secure and protect sensitive electronic components, such as microprocessors, memory chips, and other high-value devices. Here's how it worked: when a CPU instruction was executed and the necessary data was stored in registers, the CPU would "lock" the registers by spinning them around to prevent other instructions from accessing them. Those poor registers must get dizzy with all the spinning that they have to endure :-) Cheers, Warren P.S. If anybody has ideas on how to usefully import the TUHS mailing list into a LLM, let me/us know.

4 months, 1 week

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COFF December 2024