TUHS

tuhs@tuhs.org

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6534 discussions

by Warren Toomey

So what is the etymology of the word "shell"? I see that Multics has a shell. What the user interface in CTSS also called a shell? Cheers, Warren

9 years, 6 months

Mirror of Mike Mahoney's oral history of Unix

by Warren Toomey

All, Doug McIlroy sent me an e-mail about the late Mike Mahoney's project to create an oral history of Unix. His documents are at http://www.princeton.edu/~hos/Mahoney/unixhistory I've taken the liberty to mirror them into the Unix Archive and they are now also at http://minnie.tuhs.org/Archive/Documentation/OralHistory/ Cheers, Warren

9 years, 6 months

Re: [TUHS] etymology of cron

by norman＠oclsc.org

John Cowan: Wikipedia is by nature a *summary of the published literature*. If you want to get some folklore, like what "cron" stands for, into Wikipedia, then publish a folklore article in a journal, book, or similar reputable publication. Random uncontrolled mailing lists simply do not count. ====== That sounds fair enough on the surface. But if you follow the references cited to support the cron acronyms, you find that random unsupported assertions in conference papers do count. That's not a lot better. I'd like to see a published, citable reference for the true origin of `cron'. Even better, better published material for a lot of the charming minutiae of the early days of UNIX. (Anyone feel up to interviewing Doug and Ken and Brian and whoever else is left, and writing it up for publication in ;login:?) But I'd be satisfied if we could somehow stamp out the use of spurious references to support spurious claims. If I had the time and energy I'd look into how to challenge the cron acronyms on those grounds. Any volunteers? Norman Wilson Toronto ON

9 years, 6 months

Re: [TUHS] Does anybody recall how the TU10 bootstrap code actually operates?

by jnc＠mercury.lcs.mit.edu

> From: Will Senn > 000777 HALT That's actually "BR ."; the difference is important, since the CPU (IIRC) doesn't honour DMA requests when it is halted, and DMA needs to be working for the controller to read that first block (a secondary tape bootstrap) into memory. > This seems like gobbledegook to me. :-) > It moves the MTCMA (Magtape Current Memory Address) into R0, then it > moves the MTCMA into the MTBRC (Magtape Byte Record Count) "The address of the MTCMA into", etc. Looking quickly at the programming spec for the TM11 controllers, it wants a negative of the byte count to transfer in this register; the address of the MTCMA just happens to also be a large enough negative number to be usable as the (negative) size of the transfer request. (The first record is probably shorter than that, but that doesn't matter.) Note that this code could probably also have been written: MOV #172524, R0 MOV R0,@R0 and been equally functional. > then it moves 60003 into the MTC (Magtape control register), which > causes a read operation with 800BPI 9 Channel density. I'm too lazy to look at the programming spec for the details, but that sounds right. > Am I misinterpreting the byte codes or is this some idiosyncratic way to > get the Magnetic tape to rewind or something (the TM11 has a control > function to rewind, so it seems unlikely that this is the case No, it's just the shortest possible program to read the first block off the tape. It depends on i) the operator having manually set the tape to the right point (the start of the tape), so that it's the first block that gets read, and ii) the fact that the reset performed by hitting the 'Start' key on the CPU clears the TM11 registers, including the Current Memory Address register, so the block that's read is read into memory location zero. Hence the direction to 'once the tape has stopped moving, re-start the CPU at 0'. Noel

9 years, 6 months

(no subject)

by scj＠yaccman.com

Actually, I could easily see Usenix doing this kind of thing on a regular basis. Add my vote as another ex president...

9 years, 6 months

(no subject)

by scj＠yaccman.com

Actually, I could easily see Usenix doing this kind of thing on a regular basis. Add my vote as another ex president...

9 years, 6 months

Re: [TUHS] Does anybody recall how the TU10 bootstrap code actually operates?

by jnc＠mercury.lcs.mit.edu

> Thank you for responding so carefully. The devil is in the details... > I have been reading the PDP-11/40 handbook, much too much :) I'm not sure that's possible! :-) Yes, yes, I know, the architecture is deader than a doornail for serious use, but I liken it to sailing vessels: nobody uses them for serious cargo haul any more, but they are still much beloved (and for good reasons, IMO). The PDP-11 is an incredibly elegant architecture, perhaps the best ever (IMO), which remains one of the very best examples ever of how to get 30 pounds into the proverbial ten-pount sack - like early UNIX (more below). > this is really elegant code. The guys who thought this up were amazing. Nah, it's just a clever hack (small-scale). What is really, almost un-approachably, brilliant about early UNIX is the amount of functionality they got into such a small machine. It's hard to really appreciate, now, the impact UNIX had when it first appeared on the scene: just as it's impossible for people who didn't themselves actually experience the pre-Internet world to _really_ appreciate what it was like (even turning off all one's computers for a day only approximates it). I think only people who lived with prior 'small computer OS's' could really grasp what a giant leap it was, compared to what came before. I remember first being shown it in circa 1975 or so, and just being utterly blown away: the ability to trivially add arbitrary commands, I/O redirection, invisibly mountable sections of the directory tree - the list just goes on and on. Heck, it was better than all but a few 'big machine' OS's! > Thanks again for your help. Eh, de nada. Noel

9 years, 6 months

Re: [TUHS] etymology of cron

by Norman Wilson

John Cowan: Well, of course there are conferences and there are conferences. The only conference I've ever had a paper published at, Balisage, is as peer-reviewed as any journal. (And it is gold open access and doesn't charge for pages -- the storage costs are absorbed as conference overhead.) ==== Have you actually looked up the cited reference? The trouble is not that it's a conference paper. The trouble is that that the `authority' being cited is just a random assertion, not backed up. It's as if I mentioned your name in a paper about something else, remarked in passing and without any citation of my own that you have a wooden leg, and Wikipedia accepted that as proof of your prosthesis. Norman Wilson Toronto ON (Four limbs and eight eyes, thank you very much)

9 years, 6 months

Re: [TUHS] etymology of cron

by jnc＠mercury.lcs.mit.edu

On Dec 22, 2015, at 5:44 PM, Norman Wilson <norman(a)oclsc.org> wrote: > If that's the quality of reference they accept, there is simply no > reason to take anything they publish as gospel. You're mistaking Wikipedia for an information source you can rely on. It's not. It's more akin to an attempt to prove that an infinite number of monkeys, with an infinite number of typewriters, and an infinite amount of time, can produce a reliable encyclopaedia. (Yes, yes, spare me the surveys that show that Wikipedia's error rates aren't that bad, when compared with other encyclopaedias, etc.) Don't get me wrong, Wikipedia is quite useful as a place for an _introduction_ to any topic, but anyone who really wants to _reliably_ know anything about a topic needs to look at the references, not the articles. There was an attempt to do a Wikipedia-like online encyclopaedia that one could rely on - Citizendium - but alas it doesn't seem to have taken off (or hadn't when I got distracted from working on it). And I know whereof I speak; those who wish to be amused may want to read: http://en.wikipedia.org/wiki/User:Jnc/Astronomer_vs_Amateur And apologies for continuing the off-topic (this group certainly can't fix Wikipedia, people have been complaining about this problem for many years now), but some buttons, you just have to respond when they are pushed... Noel

9 years, 6 months

Re: [TUHS] etymology of cron

by Johnny Billquist

On 2015-12-23 17:04, norman(a)oclsc.org (Norman Wilson) wrote: > John Cowan: > > Wikipedia is by nature a*summary of the published literature*. If you > want to get some folklore, like what "cron" stands for, into Wikipedia, > then publish a folklore article in a journal, book, or similar reputable > publication. Random uncontrolled mailing lists simply do not count. > > ====== > > That sounds fair enough on the surface. > > But if you follow the references cited to support the cron > acronyms, you find that random unsupported assertions in > conference papers do count. That's not a lot better. I've had similar experiences with Wikipedia in the past. At one point I was trying to get the PDP-11 article corrected, as it said that the PDP-11 was an architecture that disappeared in the 80s (paraphrasing). I pointed out that the last *new* PDP-11 model from DEC itself was released in 1990, and that others are still making new PDP-11 CPUs. My corrections were reverted, and I was asked for citations. I went through a silly loop of requests for sources for my claims, while there seems to have been no demand for citation for the original claims, more than the "knowledge" of someone. It wasn't until I dug up the system manuals and documentation from DEC about the PDP-11/93 and PDP-11/94 (which have actual time of original publishing date printed) that my claims were (somewhat) accepted. I've also had numerous fights about the Wikipedia articles about virtual memory, where the original authors on the article clearly had not understood the difference between virtual memory and demand paged memory. The articles are better today, but when I last looked, they still had some details wrong in there. And getting anything corrected is hell, as any silly statement that is already in is almost regarded as gospel, and anything you try to correct is questioned to hell and back before anyone will accept it. (Hey, according to Wikipedia, a PDP-11 do not have virtual memory... I wonder what it has then. Fake memory? Although, the article might now actually accept that a PDP-11 do have virtual memory, although no OS I know of implements demand paging, but that could be done as well, if anyone wanted to.) Nowadays, I use Wikipedia to find information, but just take everything in there with a large grain of salt when it comes to details. There are just too many ignorant people who are writing stuff, and who seem to get anything accepted, and too much hassle to get anything corrected when you actually knows the subject. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

9 years, 6 months

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TUHS