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6411 discussions

by John Floren

Today I came across an article about the MGR window system for Unix: https://hack.org/mc/mgr/ One thing that interested me was a note that some versions worked on the Macintosh: > The window system ran on many different hardware platforms, at least > these: Sun 3/xx workstations running SunOS, which was the the original > development platform, Sun SPARCstations (SunOS and then ported by me to > Solaris), Intel x86 based PCs (Coherent, Minix, FreeBSD or Linux), > Atari ST (under MiNT), AT&T UnixPC (SysV) and the Macintosh. As the owner of a Macintosh Plus, I think it would be a very interesting thing to experiment with, but I haven't had much luck finding any more information about it. Does anyone know more about MGR, particularly on the Mac? That page has the source for MGR 0.69, but there's no mention of the Macintosh in it (aside from comments about how it was supported on older versions...) John

2 years, 3 months

Re: "9 skills our grandkids won't have" - Is this a TUHS topic?

by Matthias Bruestle

I know something! On Fri, Jul 01, 2022 at 04:05:30PM +0300, Ori Idan wrote: > > o why CTRL/S and CTRL/Q are used for flow control in a shell command > > line session > > > Also would be happy to know. https://en.wikipedia.org/wiki/Software_flow_control But I don't know the answer to Ctrl-D. :( And also the bus error and maybe the segmentation fault if it hasn't to do with a segment register. Matthias -- When You Find Out Your Normal Daily Lifestyle Is Called Quarantine

2 years, 3 months

Re: Does anybody know the etymology of the term "word" as in collection of bits?

by Douglas McIlroy

> I heard that the IBM 709 > series had 36 bit words because Arthur Samuel, > then at IBM, needed 32 bits to identify the playable squares on a > checkerboard, plus some bits for color and kinged To be precise, Samuel's checkers program was written for the 701, which originated the architecture that the 709 inherited. Note that IBM punched cards had 72 data columns plus 8 columns typically dedicated to sequence numbers. 700-series machines supported binary IO encoded two words per row, 12 rows per card--a perfect fit to established technology. (I do not know whether the fit was deliberate or accidental.) As to where the byte came from, it was christened for the IBM Stretch, aka 7020. The machine was bit-addressed and the width of a byte was variable. Multidimensional arrays of packed bytes could be streamed at blinding speeds. Eight bits, which synced well with the 7020's 64-bit words, was standardized in the 360 series. The term "byte" was not used in connection with 700-series machines. Doug

2 years, 3 months

Extracting files from various old dump/restore tapes

by Lars Brinkhoff

Hello, I have on my hands many images of tapes that seems to have been written by various implementaions of dump. I see the magic numbers 60011 and 60012 in little and big endian at offsets 18 (16-bit version?) and 24 (32-bit version?). I don't know the dating of the tapes, but around 1980 would be a reasonable guess. Are there some easy to use (ready to run on a modern Unix) tools to extract files from such tape files? I'm not looking to restore a file system on disk, just extract the files.

2 years, 3 months

DMD 5620 simulator

by Seth Morabito

Hello all, I've recently been improving the AT&T/Teletype DMD 5620 simulator I wrote a few years ago. It can now run either the 8;7;3 or 8;7;5 firmware. It also now supports executing a local shell or connecting directly to a physical or virtual tty device. It runs natively on Linux or macOS with X11 or Wayland, but I would love help creating a Windows version if you're a Windows programmer (I am an occasional Windows user, but I am not at all knowledgeable about Windows programming). Full details are available here: https://loomcom.com/3b2/dmd5620_emulator.html The source code is here: https://github.com/sethm/dmd_gtk Many thanks go to my friend Sark (@crtdude on Twitter) for tracking down the 8;7;3 firmware and dumping it for me. I'd also like to thank Mike Haertel for helping find bugs, providing feedback, and inspiring me to get it working with Research Unix in addition to SVR3. Feedback, bug reports, and pull requests are all welcome! -Seth -- Seth Morabito Poulsbo, WA web(a)loomcom.com

2 years, 3 months

Re: Does anybody know the etymology of the term "word" as in collection of bits?

by Douglas McIlroy

Anecdote prompted by the advent of Burroughs in this thread: At the 1968 NATO conference on Software Engineering, the discussion turned to language design strategies. I noted that the design of Algol 68, for example, presupposed a word-based machine, whereupon Burroughs architect Bob Barton brought the house down with the remark, "In the beginning was the Word, all right--but it was not a fixed number of bits!" [Algol 68's presupposition is visible in declarations like "long long long ... int". An implementation need support only a limited number of "longs", but each supported variety must have a definite maximum value, which is returned by an "environment enquiry" function. For amusement, consider the natural idea of implementing the longest variety with bignums.] Doug

2 years, 3 months

Re: [COFF] Re: Will someone update the 386BSD Wikipedia page for me?

by David Arnold

The error was introduced on 13 September 2005, by an anonymous user from an IP address allocated to Web Perception, a Californian ISP, and (currently) geolocated to Sonoma. The change comment was: Changes - 386BSD factual errors corrected, potentially libelous statements removed, links updated, refocus on 386BSD history, authority-386BSD authors, published works, DMR refs The same IP address was used for a series of edits over 2005-2006, to topics including 386BSD, Lynne Jolitz, William Jolitz, and Radiocarbon Dating. I imagine it was simply a mistake. d > On 10 Sep 2022, at 12:26, Grant Taylor via COFF <coff(a)tuhs.org> wrote: > > On 9/9/22 8:05 PM, Greg 'groggy' Lehey wrote: >> Done. > > Thank you! > >> Do you have an idea about how this error crept in? > > No, I do not. > > I came to this article after reading about the DDJ DVD archive on the geeks mailing list. I was sensitive to the emails about DDJ because I've been looking to acquire the issues (or at least articles) with the Porting Unix to the 386 articles in them. > > Now I have them! :-D > > > > -- > Grant. . . . > unix || die >

2 years, 3 months

Happy birthday, Unix timestamp!

by Dave Horsfall

https://www.timeanddate.com/on-this-day/september/9 ``Unix time or Unix epoch, POSIX time or Unix timestamp, is a time system that measures the number of seconds since midnight UTC of January 1, 1970, not counting leap seconds. At 01:46:40 UTC on September 9, 2001, Unix time reached the billionth second timestamp.'' Hard to believe that it was that long ago... -- Dave

2 years, 3 months

Re: Does anybody know the etymology of the term "word" as in collection of bits?

by Nelson H. F. Beebe

Paul Winalski and Bakul Shah commented on bit addressable machines on the TUHS list recently. From Blaauw and Brooks' excellent Computer Architecture book http://www.math.utah.edu/pub/tex/bib/master.html#Blaauw:1997:CAC on page 98, I find >> ... >> The earliest computer with bit resolution is the [IBM 7030] Stretch. >> The Burroughs B1700 (1972) and CDC STAR100 (1973) are later examples. >> >> Bit resolution is costly in format space, since it uses a maximum >> number of bits for address and length specification. Sharpening >> resolution from the byte to the bit costs the same as increasing >> address-space size eight-fold. >> >> Since almost all storage realizations are organized as matrices, >> bit resolution is also expensive in time or equipment. >> ... ------------------------------------------------------------------------------- - Nelson H. F. Beebe Tel: +1 801 581 5254 - - University of Utah - - Department of Mathematics, 110 LCB Internet e-mail: beebe(a)math.utah.edu - - 155 S 1400 E RM 233 beebe(a)acm.org beebe(a)computer.org - - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe/ - -------------------------------------------------------------------------------

2 years, 3 months

Re: Does anybody know the etymology of the term "word" as in collection of bits?

by norman＠oclsc.org

Doug McIlroy: Bit-addressing is very helpful for manipulating characters in a word-organized memory. The central idea of my ancient (patented!) string macros that underlay SNOBOL was that it's more efficient to refer to 6-bit characters as living at bits 0,6,12,... of a 36-bit word than as being characters 0,1,2,... of the word. I've heard that this convention was supported in hardware on the PDP-10. ==== Indeed it was. The DEC-10 had `byte pointers' as well as (36-bit) word addresses. A byte pointer comprised an address, a starting bit within the addressed word, and a length. There were instructions to load and store an addressed byte to or from a register, and to do same while incrementing the pointer to the next byte, wrapping the start of the next word if the remainder of the current word was too small. (Bytes couldn't span word boundaries.) Byte pointers were used routinely to process text. ASCII text was conventionally stored as five 7-bit bytes packed into each 36-bit word. The leftover bit was used by some programs as a flag to mean these five characters (usually the first of a line) were special, e.g. represented a five-decimal-digit line number. Byte pointers were used to access Sixbit characters as well (each character six bits, so six to the word, character set comprising the 64-character subset of ASCII starting with 0 == space). Norman Wilson Toronto ON (spent about four years playing with TOPS-10 before growing up to play with UNIX)

2 years, 3 months

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