Posts by hendrikboom3@qoto.org
(DIR) Post #9fVbTVXgod23MPbCpE by hendrikboom3@qoto.org
2019-02-05T01:03:40Z
0 likes, 0 repeats
@federationbot Go ahead and follow me if you like.
(DIR) Post #9fVbV8s44uLJcquP6e by hendrikboom3@qoto.org
2019-02-05T01:04:44Z
0 likes, 0 repeats
@freemo A slower version could be an acoustic delay line.
(DIR) Post #9fWre6HoqkdudmCzuy by hendrikboom3@qoto.org
2019-02-05T15:40:21Z
0 likes, 0 repeats
@freemo The Bendix G-15d computer used delay lines on a magnetic drum. The spacing between read and write heads determined the delay.Those delay lines contained the main memory *and* the registers (such as the arithmetic accumulator).
(DIR) Post #9fX6YsE3CNfytdPaHA by hendrikboom3@qoto.org
2019-02-05T18:27:30Z
0 likes, 0 repeats
@freemo No, I did mean a real magnetic drum on this machine, acquired by the university in 1957. I got to use it in1962. I spent a happy summer hanging about the university's air-conditioned computer room reading its circuit diagrams to learn how it operated. It was a truly magnificent kludge.Main memory consisred of a number of these recirculating tracks, each was 108 words of 29 bits each -- 7 hex digits and a sign bit. The instructions had a source memory line, a destination memory line, and specifications when the instruction was to be executed and when the next one was to be read. These times were essential -- they determined which words were being read and rewritten and thus possibly modified as the drum turned.
(DIR) Post #9fX6zKcuEA18Vdeahs by hendrikboom3@qoto.org
2019-02-05T18:32:18Z
0 likes, 0 repeats
@freemo I wasn't aruond for the mercury delay lines. They were from the 40's and 50's, right? And you can still get them nowadays? I didn't get into computing until '62. I remember reading about William's tube memories. Why do I get the idea they were grasping at straws back then to get anything, just anything, to work?
(DIR) Post #9fXMpk3qPFcxlPheU4 by hendrikboom3@qoto.org
2019-02-05T18:37:16Z
0 likes, 0 repeats
The Bendix used a magnetic drum Each memory line had a read head and a write head. Normally whatever was read would be written immediately, and would then travel around with drum rotation until it got bach to the read head and repeat the cycle.
(DIR) Post #9fXWdDm3cagnh73Gpk by hendrikboom3@qoto.org
2019-02-05T23:19:37Z
0 likes, 0 repeats
@freemo These were still the early days of computing. When did they first start using disks with addressable permanent random-access storage? I don't know, but the first I saw myself appeared on another computer years after this Bendix was made. The Bendix was donated to tge university in 1957 by Pioneer Electric on condition that ghey could continue to use it for transformer design calculations. I do not mnow how old it was when it was donated. I do know it had lots and lots of vacuum tubes.I do know that this ever recirculating memory was basic to the machine's design.There were a few short memory lines of only one or two or four wordsmlong. These were used the way we use registers now. And a few destinations were special circuitry instead of being regular memry lines. The one-word accumulator was two destinations -- one for the usual write process, where you could provide new data to replace what would otherwise be rewritten, and the other that you used to add to what otherwise would be rewritten. So by specifying that a data transfer was to happen for multiple word times, you would end up adding multiple words from the source memory line to the accumulator. One instruction, no loop, many numbers added.The drum was treated as volatile memory.
(DIR) Post #9fXYC8kkNj5GD9eZY8 by hendrikboom3@qoto.org
2019-02-05T23:37:10Z
0 likes, 0 repeats
@freemo A question oof course is whether the so-called property that is used to define the paradixical Russel set is a property at all or merely nonsense. Attempting to determine whether that set is a member of itself leads to infinite recursion.I see this as indicating something about sets. We are used to thinking of sets as justbexisting somewhere and we are discovering their properties. But I'm a constructivist, and view our membership conditions as a kind of construction of sets. It's possible to use language to describe all kinds of nonsense, and this one is nonsense.Not that I mind such nonsense. It's fun. I read fantasy nivels, too, and they're fun.But trying to build fantasy set theories that can admit such descriptions if fraught with difficulty. You have to avoid plot holes.
(DIR) Post #9fXbzQdMzN7JiiOfNA by hendrikboom3@qoto.org
2019-02-06T00:19:40Z
0 likes, 0 repeats
@freemo The wikipedia has a nice write-up:https://en.m.wikipedia.org/wiki/Bendix_G-15
(DIR) Post #9fZ0SG6tmqllXNRtYm by hendrikboom3@qoto.org
2019-02-06T16:28:29Z
0 likes, 0 repeats
@freemo What's interesting, of course, is the *way* it's nonsense. In putting together ZF set theory they found ways to forbid the paradox while still allowing the useful things mathematicians were doing with sets. But there seem to have been multiple attempts to patch it all up, and the one in ZF has gained popularity.As for what is actually *true* in set theory, I suspect there is no objective way of answering that.Mathematical philosophers are still working on ways to make logics that allow the Russel set without its paradoxical nature infecting the rest of the set theory.See for example, Kevin Sharp's note http://kevinscharp.com/ScharpPhilosophyandDefectiveConceptsHandout.pdfThe book he refers to is "Replacing Truth", available for money at Oxford University Press. Or maybe in a library. It may be more detailed than you want to get into.
(DIR) Post #9fdCx9mufGaT5I455M by hendrikboom3@qoto.org
2019-02-08T17:07:21Z
0 likes, 0 repeats
@freemo Which brings up, I suppose, whether any method of reasoning, any approximate understanding, can ever be considered 'true'. That's a philosophical quagmire I don't want to get into, because I suspect there ix no way out.
(DIR) Post #9fnJvMfcrupSuJeODA by hendrikboom3@qoto.org
2019-02-13T14:12:35Z
0 likes, 0 repeats
@freemo @twdockery We occasionally get some sane politics here in Canada. Perhaps that's because everything has to compromise between Quebec and the West. But Canada isn't really a counterexample because it's not really English-speaking, being about a third French.Quebec itself, no not that much sane politics.
(DIR) Post #9iT6feXuoZfMADMWRM by hendrikboom3@qoto.org
2019-05-04T13:46:07Z
0 likes, 0 repeats
@freemo It's still absurd, but killing them wouldn't help. And it's not Bernie Sanders saying to kill them. A violent revolution is dangerous to all, and often just yields a dictatorship worse than the old regime.
(DIR) Post #A0bbeDzwwDhqODrRSa by hendrikboom3@qoto.org
2020-10-28T01:48:26Z
0 likes, 0 repeats
@freemo yes. Bi see it and it is animated.
(DIR) Post #ANuHzG88mrPkpfz5m4 by hendrikboom3@qoto.org
2022-09-25T01:06:26Z
0 likes, 0 repeats
@freemo dolphins?
(DIR) Post #ASBKkawxHPW9KCl5OK by hendrikboom3@qoto.org
2023-01-30T21:55:56Z
0 likes, 0 repeats
@freemo I'm currently using Devuan, but I've wondered about NixOS and Guix. I seem to remember one of these is based on Scheme? Possibly Guile?
(DIR) Post #ASBMddfUySXJdZP7Cq by hendrikboom3@qoto.org
2023-01-30T22:17:03Z
0 likes, 0 repeats
@freemo Do either of NixOS and Guix support tge same style of dual booting as Devuan and Debian so I can choose OS's at coot time? Do their package managers fit insidevanother OS?