TUHS

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6532 discussions

4.1c bsd ptrace man entry ("ptrace is unique and arcane")

by ron minnich

I always wondered who wrote this, anyone know? I have my suspicions but ... ".SH BUGS .I Ptrace is unique and arcane; it should be replaced with a special file which can be opened and read and written. The control functions could then be implemented with .IR ioctl (2) calls on this file. This would be simpler to understand and have much higher performance." it's interesting in the light of the later plan 9 proc interface. ron

6 years

OT: Need help getting old 9 track tapes read

by arnold＠skeeve.com

Hi All. Scott Lee, who worked with me on the Georgia Tech Software Tools Subystem for Pr1me Computers, recently unearthed two tapes with some version of that software. These may be the only copies extant anywhere. He says: | I was cleaning out the basement of my house. They're 35 years old, but | they've never been left in the heat or anything. I opened one of them | up and checked the tape and it's not self-sticky or anything. The odds | that they're readable is slim, because old 9-track bits tended to bleed | through each other. You were supposed to spin through the tape every | couple of years to make them last longer. That's obviously not happened. There was discussion here a while back about services that will recover such tapes and so on. But I didn't save any of that information. If you have information, PLEASE send it to me so that I can relay it to Scott. Dennis Boone & Bill Gunshannon (are you on this list?) - I may ask you to contribute $$ towards this once I know more. Thanks! Arnold

6 years

Re: [TUHS] CMU Mach sources?

by jnc＠mercury.lcs.mit.edu

> From: Andrew Warkentin > Mach and the other kernels influenced by it basically destroyed the > reputation of microkernels ... a simple read() of a disk file, which is > a single kernel call on a monolithic kernel and usually two context > switches on QNX, takes at least 8 context switches - client->VFS->disk > FS->partition driver->disk driver and back again). Hammer-nail syndrome. When the only tool you have for creating separate subsystems is processes, you wind up with a lot of processes. Who'd a thunk it. A system with a segmented memory which allows subroutine calls from one subsystem to another will have a lot less overhead. It does take hardware support to be really efficient, though. The x86 processors had that support, until Intel dropped it from the latest ones because nobody used it. Excuse me while I go bang my head on a very hard wall until the pain stops. Noel

6 years

Any oldtimers remember anything about the KS11 on the -11/20?

by jnc＠mercury.lcs.mit.edu

This is an appeal to the few really-old-timers (i.e. who used the PDP-11/20 version of Unix) on the list to see if they remember _anything_ of the KS11 memory mapping unit used on that machine. Next to nothing is known of the KS11. Dennis' page "Odd Comments and Strange Doings in Unix": https://www.bell-labs.com/usr/dmr/www/odd.html has a story involving it (at the end), and that is all I've ever been able to find out about it. I don't expect documentation, but I am hoping someone will remember _basically_ what it did. My original guess as to its functionality, from that page, was that it's not part of the CPU, but a UNIBUS device, placed between the UNIBUS leaving the CPU, and the rest of the the bus, which perhaps mapped addresses around (and definitely limited user access to I/O page addresses). It might also have mapped part of the UNIBUS space which the -11/20 CPU _can_ see (i.e. in the 0-56KB range) up to UNIBUS higher addresses, where 'extra' memory is configured - but that's just a guess; but it is an example of the kind of info I'd like to find out about it - just the briefest of high-level descriptions would be an improvement on what little we have now! On re-reading that page, I see it apparently supported some sort of user/kernel mode distinction, which might have require a tie-in to the CPU. (But not necessarily; if there was a flop in the KS11 which stored the 'CPU mode' bit, it might be automatically cleared on all interrupts. Not sure how it would have handled traps, though.) Even extremely dim memories will be an improvement on the blank canvas we have now! Noel

6 years

Re: [TUHS] Any oldtimers remember anything about the KS11 on the 11/20?

by jnc＠mercury.lcs.mit.edu

> From: Rudi Blom > Probably already known, but to be sure Interesting options: MX11 - > Memory Extension Option: this enabled the usage of 128 KW memory (18-bit > addressing range) Actually, I didn't know of that; something else to track down. Wrong list for that, though. Noel

6 years

Any oldtimers remember anything about the KS11 on the 11/20?

by Rudi Blom

Probably already known, but to be sure Interesting options: MX11 - Memory Extension Option: this enabled the usage of 128 KW memory (18-bit addressing range); KS11: this option provided hardware memory protection, which the plain /20 lacked. Both options were developed by the Digital CSS (Computer Special Systems). http://hampage.hu/pdp-11/1120.html PS the page listed below has a very nice picture of the 'two fathers of UNIX" working on a PDP-11/20 http://hampage.hu/unix/unix1.html

6 years

Re: [TUHS] UNIX 50th at USENIX ATC

by Norman Wilson

Kevin Bowling: The conference looks supremely uninteresting outside one WAFL talk to me. ==== That is, of course, a matter of opinion. Just from skimming titles I see about two dozen talks of at least some interest to me in the ATC program. And that's just ATC; I'm planning to attend the Hot* workshops on Monday and Tuesday as well. Of course I won't attend every one of those talks--some coincide in time, some I'll miss because I get stuck in the hallway track. And some will prove less interesting in practice, though others that don't seem all that interesting in the program will likely prove much better in person. I've been attending USENIX ATC for decades, and although some conferences have been meatier than others, I've never ended up feeling the trip was a waste of time. Perhaps us old farts just aren't as discriminating as you youngsters. That said, I think Kevin's question Is there a way to participate [on the UNIX50 event] without attending Usenix ATC? is a good one. Norman Wilson Toronto ON

6 years

RIP Bud Lawson

by Doug McIlroy

Bud Lawson, long an expat living in Sweden, died yesterday. Not a Unix person, he was, however, the originator of a characteristic Unix programmer's idiom. Using an idea adapted from Ken Knowlton, Bud invented the pointer- chasing arrow operator that Dennis Ritchie adopted for C. I played matchmaker. When Bud first proposed the "based storage" (pointer) facility for PL/I, he used the well-established field(pointer) notation. I introduced him to the pointer-chasing notation Knowlton devised for L6. Knowlton, however, had no operator because he had only single-letter identifiers. What we now write as a->b->c, Knowlton wrote as abc. Appreciating the absence of parentheses, Bud came up with the wonderfully intuitive pointer->field notation. Doug

6 years

MtXinu floppy set for Mach386

by Jason Stevens

I came across Scott Taylor’s site which mentions his adventure with MtXinu (https://www.retrosys.net/) I had asked a few years ago (February 2017?) about locating a set Of this to no avail, but thanks to Scott the binary set is now available. ftp://ftp.mrynet.com/operatingsystems/Mach2.5/MtXinu-binary-dist/floppies/M… There is some additional documentation to be found here. ftp://ftp.mrynet.com/operatingsystems/Mach2.5/MtXinu-binary-dist/docs The floppy drive like 386BSD is super weak and I had no luck with Qemu. VMWare worked fine to install. The VMDK will run on Qemu as low as 0.90 just fine. I haven’t tried the networking at all, so I don’t know about adapters/protocol support. I’ve been using a serial line to uuencode stuff in & out but it’s been stable.

6 years

Celebration of Internet History with their UNIX at 50 Event

by Clem Cole

We are all thrilled and thankful for the generosity of SDF and LCM+L by sponsoring and providing a celebration of Internet History with their UNIX at 50 Event for the USENIX ATC Attendees. We understand not all of you can participate in the conference, but would still like to be part of the celebration. Our hosts have graciously opened the event to the community at large, as I said in my previous message, it should be an evening of computer people being able to be around and discussing computer history. However, if you are not planning to attend the conference but wish to attend the evening's event, we wish that you would at least consider joining one or more of the organizations to help support them all in the future. All three organizations are members supported and need all our help and contributions to function and bring their services to everyone today and hopefully 50 years from now. Membership details for each can be found at Join SDF <https://sdf.org/join>, LCM+L Memberships <https://livingcomputers.org/Join/Memberships.aspx>, and USENIX Association Memberships <https://www.usenix.org/membership-services> ᐧ

6 years

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