TUHS

tuhs@tuhs.org

49 participants
6506 discussions

by Warner Losh

In honor of the Unix 50 party tomorrow, I wrote an analysis of the available data to conclude the first PDP-7 that Ken and Dennis used to bring up Unix on was serial number 34. I've not seen this result elsewhere, but if it's common place, please let me know. https://bsdimp.blogspot.com/2019/07/the-pdp-7-where-unix-began.html One surprise from the analysis: there was only one pdp-7 in the world that could have run the original v0 unix. It's the only one that had the RB09 hard drive (though the asset list referenced in the article listed a RC09 on that system). I hope you enjoy Warner

5 years, 10 months

UREP

by Lyndon Nerenberg

Back in the day I had the pleasure of firing up what was possibly the last North American BITNET node (certainly the last one on NetNorth), on a Sun 3/xxx deskside server running SunOS 3.5(+). (AUCS, at Athabasca U.) I'm curious to know if the UREP source code that drove that link ever escaped. I recall it being licensed code at the time, but from academia vs. a commercial product. I don't know if that also applied to the bisync serial driver. --lyndon

5 years, 10 months

Re: [TUHS] Plot 10 Sources

by jnc＠mercury.lcs.mit.edu

> From: "Nelson H. F. Beebe" > In our PDP-10 TOPS-20 archive of what was then utah-science .. I find > these files: Thanks very much for doing that search, and congratulations on finding them! Not that I have the slightest interest/use in the results, but it's so good to see historical software being saved. Noel

5 years, 10 months

IEEE Computing Edge and Unix history

by Nelson H. F. Beebe

Postal mail today brought me the latest issue of the IEEE Computing Edge magazine, which presents short articles from other recent IEEE publications. In it, there is an article with numerous mentions of Doug McIlroy, early Unix, software tools, and software modularization: Gerard J. Holzmann Software Components IEEE Computing Edge 5(7) (July 2019) 38--40 https://ieeexplore.ieee.org/document/8354432 [republished from IEEE Software 35(3) (May/June 2018) 80--82] ------------------------------------------------------------------------------- - Nelson H. F. Beebe Tel: +1 801 581 5254 - - University of Utah FAX: +1 801 581 4148 - - 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/ - -------------------------------------------------------------------------------

5 years, 10 months

Re: [TUHS] groff_man question

by Doug McIlroy

I wouldn't call it an error, merely a misleading sentence. .EX/.EE is, after all, an extension in Gnu, albeit not original to Gnu. And I didn't intend to impugn anybody. The sentence, "Ingo Schwarze stated incorrectly" was apparently slipped into the quotation to provide missing context. I do appreciate, however, how quickly the inexactness was repaired. Doug | Doug McIlroy wrote on Mon, Jul 08, 2019 at 11:17:32PM -0400: | > Ingo Schwarze stated incorrectly: | | >> EE This is a non-standard GNU extension. In mandoc(1), it does the | >> same as the roff(7) fi request (switch to fill mode). | | >> | >> EX This is a non-standard GNU extension. In mandoc(1), it does the | >> same as the roff(7) nf request (switch to no-fill mode). | | > "Gnu extension" should be read as "extension adopted by Gnu". | > .EX/.EE was introduced in 9th Edition Unix. | | Thank you for pointing out the error, i corrected the manual page | in OpenBSD and in portable mandoc, see the commit below.

5 years, 10 months

Weird files in the archive

by Warner Losh

Just sync my personal copy with the tuhs archive. Looks like there are a lot of Mac preview files (that start with ._) mixed in. Is that on purpose? Warner

5 years, 10 months

Testing...

by Dave Horsfall

Sorry for the noise, but this list is awfully quiet. -- Dave

5 years, 10 months

Classic / NOP machines becoming available in Berlin (inc. DECs, Commodores, Apples, HPs, SGIs and more)

by Peter Dreisiger

Dear all, Apologies for this semi-spam message from a long-time appreciator of classic computers and nostalgic obsolete products, but I hope this will be of interest to at least a few people here. So, yes, by way of context, I've been acquiring what I consider to be characterful and/or historically interesting computers for coming up to, maybe, 15 years now, with the intention of being able to curate multiple, interactive temporary exhibits on the history of computing, but since moving continents (amongst other things), my paths and passions have changed, so I am currently in the process of re-testing (and repairing) my machines, and will be trying to sell them off in the coming weeks and months. Under different circumstances, finding people (or groups) with similar interests and plans would have been an equal-first priority, but given my more recent 'life changes', sale price — and the ability to better pursue my new focuses — is now more of a factor. (That said, if you are (or know) a developer of an open source machine emulator who could use one of these machines --- particularly one of the more obscure ones --- please do get in touch, as the prospect of people being able to keep older / rarer operating systems and software running once the physical machines are not longer available or working /is/ actually still kinda important to me, and I'd be open to a lower price and/or setting up some remote access with some kind of kludged-together iLO and vaguely 'dual-ported' disk access via, e.g., an SD2SCSI setup.) But before I list them on eBay (and/or by way of a heads up), I wanted to let people here know, just in case I have something that someone here particularly wants / needs / could use. The current list of systems I will be parting with is accessible at https://docs.google.com/spreadsheets/d/1QqUrO11gnn4fwAPDxqO_phKDt1M0O15G7wJ… but some (hopefully) highlights include (*big breath*): DEC: MicroPDP-11/53+; MicroVAX 2000; VAXstation 4000 VLC/60/90A/96; VAX 4000 100A, 105; DECstation 5000/240, 260 (MIPS-based); DEC 3000/300X; Personal Workstation 600au; AlphaServer 4100; AlphaServer DS20, DS25 systems; Letterwriter 100; VT 101, 220, 520 terminals HP: HP rx2800 Integrity2; 9000 715/100 and Visualize C110 PA-RISC systems SGI: Indy and O2 systems SUN: ELC, SPARCstation Voyager (the portable one), 5 and 20; Ultra 1; Ultra 5; Netra T1-105; Enterprise T5240 Apple: IIc, IIe Platinums, IIgs; Mac 512ke, Mac Pluses; SE/30 and Quadra 700s (also for running A/UX); iMac G3s and a G4 Commodore: PET 3000 systems, PET 8032-SK; various C64 / C64C and 128D systems; SX-64; Music Maker keyboards (the big one, inc. SFX modules); Amiga 1000 Apologies again, please feel free to contact me with any queries or reasonable offers, or even if you'd just like to be kept in the loop as more machines become available, and all the best. Thanks in advance, Peter P.S. In light of the responses I've received to posts I've made elsewhere, I've included a 'Default Reserve' price in the aforementioned spreadsheet. I've written more about this there, but the gist of it is that, given that very few of the more obscure / awesome machines have gone through eBay recently, it's kinda hard for me to gauge what a fair and reasonable (to me and the future buyers) price is for quite a few of my machines --- I've started to put in rough figures for /some/ of them based upon 'what feels right', but if there's nothing there, please don't ask me what I might want for them as I don't know yet (though do feel free to make me an offer). Thanks again!

5 years, 10 months

Mach 2.5 / MK35 booting on i386 (was CMU Mach sources?)

by Jason Stevens

As promised here is the diff & misc info on the build. I installed the Mt Xinu disks to create a build environment and uucp’d the sources from CD#4 of Kirks’ CSRG set (/local/MACH/386/sys). Grepping the source reveals it to be MK35. Which makes sense from the release notes as this was an i386 only release: ------8<------8<------8<------8< ***** MK Version MK35 (rvb) ***** This is an I386 architecture release only. It has been tested on an AT as well as the hypercube. No New features: --- -------- Except possibly that the if_pc586.c is not timing dependent any more. The big deal about this release is that all the files in the i386at directory and the files in Mach2.5 I386q are identical -- that is all improvements in the mainline have been merged to the 3.0 code and vice versa. NOTE: the 3.0 com driver has not been tested cause I did not have any hardware. Also I have lpr and if_par drivers that I did not even install for the same reason. (I needed to install com.c for the mouse support code.) ALSO, this release has the Prime copyrights changed to something less threatening, courtesy of Prime Computer Inc. Bug fix: The panic that rfr reported with the ram_to_ptr is no longer possible. ------8<------8<------8<------8< For people who like DMESG’s here it is: ------8<------8<------8<------8< boot: 442336+46792+115216[+38940+39072] Insert file system Sÿ boot: memory from 0x1000 to 0x7d0000 Kernel virtual space from 0xc0000000 to 0xc25d0000. Available physical space from 0xa000 to 0x7d0000 i386_init: virtual_avail = c07d0000, virtual_end = c25d0000 end c01938d8, sym c01938dc(981c) str = c019d0f8(98a4) [ preserving 78016 bytes of symbol table ] Mach/4.3 #5.1(I386x): Wed Jan 20 00:45:55 WET 1988; obj/STD+WS-afs-nfs (localhost) physical memory = 7.81 megabytes. vm_page_free_count = 689 using 200 buffers containing 0.78 megabytes of memory available memory = 5.55 megabytes. vm_page_free_count = 58e fdc0: port = 3f2, spl = 5, pic = 6. fd0: port = 3f2, spl = 5, pic = 6. (controller 0, slave 0) fd1: port = 3f2, spl = 5, pic = 6. (controller 0, slave 1) com0: port = 3f8, spl = 6, pic = 4. (DOS COM1) lpr0: port = 378, spl = 6, pic = 7. par0: port = 378, spl = 6, pic = 7. root on `b ------8<------8<------8<------8< The diff from the CD is as follows: ------8<------8<------8<------8< jsteve@2006macpro:/mnt/c/temp/csrg$ diff -ruN sys mach25-i386 diff -ruN sys/Makeconf mach25-i386/Makeconf --- sys/Makeconf 1970-01-01 08:00:00.000000000 +0800 +++ mach25-i386/Makeconf 2019-06-24 15:24:49.000000000 +0800 @@ -0,0 +1,102 @@ +# +# Mach Operating System +# Copyright (c) 1989 Carnegie-Mellon University +# All rights reserved. The CMU software License Agreement specifies +# the terms and conditions for use and redistribution. +# +# +# HISTORY +# $Log: Makeconf,v $ +# Revision 2.16 91/09/25 18:51:17 mja +# Fix VAX_CONFIG so that processor number component is last (for +# SUP wild-carding to work); make MMAX_CONFIG consistent with +# other platforms as STD+ANY+EXP+64. +# [91/09/25 18:41:59 mja] +# +# Revision 2.15 91/09/24 20:07:07 mja +# Require new ${KERNEL_SERIES} macro in place of old ${RELEASE} +# even to specify the "latest" series; add temporary +# ${ENVIRON_BASE}; add silent include of Makeconf-local. +# [91/09/22 03:16:36 mja] +# +# Add SITE; set SOURCEDIR to MASTERSOURCEDIR if present (for build). +# [91/09/21 18:06:08 mja] +# +# Revision 2.14 91/08/30 09:37:19 berman +# Set up default config for MMAX which is STD+MP (multiprocessor) +# [91/07/30 12:19:40 ern] +# +# Revision 2.13 91/04/02 16:04:53 mbj +# Added {I,AT}386_CONFIG=STD+WS+EXP lines. +# Changed ${MACHINE} references to ${TARGET_MACHINE}. +# +# Revision 2.12 90/08/30 12:24:52 bohman +# Changes for mac2. +# [90/08/28 bohman] +# +# Revision 2.11 89/09/25 22:43:32 mja +# Correct mis-merged OBJECTDIR. +# +# Revision 2.10 89/09/25 22:20:03 mja +# Use SOURCEDIR instead of VPATH for shadowing. This means we +# can do away with the SRCSUFFIX stuff which "make" does by +# itself, and that Makefiles can use VPATH themselves. I also +# "simplified" the definition of CONFIG and "release_...". +# [89/07/06 bww] +# +# Revision 2.9 89/08/08 21:44:58 jsb +# Defined PMAX_CONFIG. +# [89/08/03 rvb] +# +# Revision 2.8 89/07/12 23:02:52 jjc +# Defined SUN4_CONFIG. +# [89/07/12 23:01:03 jjc] +# +# Revision 2.7 89/04/10 00:34:59 rpd +# Changed OBJECTDIR name to correspond to new organization. +# [89/04/06 mrt] +# +# Revision 2.6 89/02/25 14:12:18 gm0w +# Changes for cleanup. +# +# Revision 2.5 89/02/25 14:08:30 gm0w +# Changes for cleanup. +# +# Revision 2.4 88/11/14 15:04:01 gm0w +# Changed the standard configurations to correspond +# to the new names. +# [88/11/02 15:45:44 mrt] +# +# Revision 2.3 88/09/07 15:44:43 rpd +# Moved CONFIG macros here from Makefile, so that the user +# can easily customize them by modifying Makeconf. +# [88/09/07 01:52:32 rpd] +# +# Revision 2.2 88/07/15 15:11:46 mja +# Created. +# + +VAX_CONFIG = STD+ANY+EXP+16 +mac2_CONFIG = MACMACH-macos_emul +I386_CONFIG = STD+WS+EXP +AT386_CONFIG = STD+WS+EXP +MMAX_CONFIG = STD+ANY+EXP+64 + +#CONFIG = ${${TARGET_MACHINE}_CONFIG?${${TARGET_MACHINE}_CONFIG}:STD+ANY+EXP} +#CONFIG = STD+WS+EXP-afs-nfs +CONFIG = STD+WS-afs-nfs + +SITE = CMUCS + +SOURCEDIR = ${MASTERSOURCEDIR?${MASTERSOURCEDIR}:${SRCBASE}} + +#OBJECTDIR = ../../../obj/@sys/kernel/${KERNEL_SERIES} +OBJECTDIR = ./obj + +# XXX until build is fixed to set these XXX +ENVIRON_BASE = ${RELEASE_BASE} + +.EXPORT: ENVIRON_BASE + +# Provide for private customizations in a shadow directory +-include Makeconf-local diff -ruN sys/Makefile mach25-i386/Makefile --- sys/Makefile 2016-08-08 14:37:11.000000000 +0800 +++ mach25-i386/Makefile 2019-06-24 15:24:49.000000000 +0800 @@ -206,6 +206,12 @@ at386_cpu=i386 sun4_cpu=sun4 cpu=$(${machine}_cpu) +#echo "CPU IS $cpu" +AT386_cpu=i386 +I386_cpu=i386 +cpu=${${TARGET_MACHINE}_cpu?${${TARGET_MACHINE}_cpu}:${target_machine}} +#echo "CPU IS $cpu" + VAX_OUTPUT=Makefile SUN_OUTPUT=Makefile diff -ruN sys/conf/newvers.sh mach25-i386/conf/newvers.sh --- sys/conf/newvers.sh 2016-08-08 14:37:11.000000000 +0800 +++ mach25-i386/conf/newvers.sh 2019-06-24 15:25:15.000000000 +0800 @@ -56,8 +56,17 @@ v="${major}.${minor}(${variant}${edit}${patch})" d=`pwd` h=`hostname` t=`date` CONFIG=`cat vers.config` if [ -z "$d" -o -z "$h" -o -z "$t" -o -z "${CONFIG}" ]; then - exit 1 +# exit 1 +edit="386" +major=5 +minor=1 +variant="I" +patch="x" +copyright="/copyright.txt" +v="${major}.${minor}(${variant}${edit}${patch})" d=`pwd` h=`hostname` t=`date` fi +# + d=`expr "$d" : '.*/$[^/]*$/[^/]*$'`/${CONFIG} ( /bin/echo "int version_major = ${major};" ; diff -ruN sys/i386/start.s mach25-i386/i386/start.s --- sys/i386/start.s 2016-08-08 14:37:11.000000000 +0800 +++ mach25-i386/i386/start.s 2019-07-01 23:47:25.208021800 +0800 @@ -210,13 +210,14 @@ lgdt (%eax) + / flip cr3 before you flip cr0 + mov %edx, %cr3 + / turn PG on mov %cr0, %eax or $PAGEBIT, %eax mov %eax, %cr0 - mov %edx, %cr3 - ljmp $KTSSSEL, $0x0 / ********************************************************************* diff -ruN sys/standi386at/boot/disk.c mach25-i386/standi386at/boot/disk.c --- sys/standi386at/boot/disk.c 2016-08-08 14:37:11.000000000 +0800 +++ mach25-i386/standi386at/boot/disk.c 2019-07-01 23:51:11.261850100 +0800 @@ -340,11 +340,11 @@ #ifndef FIND_PART *rel_off = vp->part[part].p_start; - if (vp->part[part].p_tag != V_ROOT) + if (vp->part[part].p_flag != V_ROOT) printf("warning... partition %d not root\n", part); #else for (i = 0; i < vp->nparts; i++) - if (vp->part[i].p_tag == V_ROOT) + if (vp->part[i].p_flag == V_ROOT) break; if (i == vp->nparts) { ------8<------8<------8<------8<

5 years, 10 months

reviving timbl's WorldWideWeb browser on NEXTSTEP 486 on Dell JAWS

by Charles H Sauer

https://notes.technologists.com/notes/2019/07/01/koko-reviving-timbls-world… While trying to get back to Dell UNIX Ethernet support in VirtualBox, I ended up reviving Tim’s CERN browser... *July 1, 2019 -- * *tl;dr sustaining Dell UNIX <https://notes.technologists.com/notes/?p=1108> -> prolonging JAWS <https://notes.technologists.com/notes/?p=1135> -> exploring NEXTSTEP 486 <https://notes.technologists.com/notes/?p=1146> -> reviving timbl's <https://notes.technologists.com/notes/?p=1150>WorldWideWeb browser <https://notes.technologists.com/notes/?p=1150>* just *k*eepin' *o*n *k*eepin' *o*n permanent reference link <https://technologists.com/tidbits/tidbit190701.html> pixel "Genghis Khan and his brother Don Could not *k*eep *o*n *k*eepin' *o*n" (1971) "You Ain't Goin' Nowhere" <https://smile.amazon.com/dp/B00136RXKK/> - Bob Dylan Charlie -- voice: +1.512.784.7526 e-mail:sauer@technologists.com fax: +1.512.346.5240 Web:https://technologists.com/sauer/ Facebook/Google/Skype/Twitter: CharlesHSauer

5 years, 10 months

CMU Mach sources?

by Jason Stevens

I finally got a chance to talk to someone who knows a hell of a lot about the i386 than I could ever hope to know. I gave him all the materials and I think he spent more time replying to my email than doing the debugging. Basically the registers for entering protected mode with paging are backwards. This is kind of funny as the port was done by Intel of all people. Anyway I reversed them and I now have the Mach kernel from 1988 booted under VMware. I have to say that it's super cool to finally have chased this one down.

5 years, 10 months

Test, please ignore

by Warren Toomey

This e-mail going to the TUHS and Dave Horsfall to see if he's getting the mail from the list. Please ignore. Warren

5 years, 11 months

CMU Mach sources?

by Chris Hanson

Does anyone know whether CMU’s local Mach sources have been preserved? I’m not just talking about MK84.default.tar.Z and so on, I’m talking about all the bits of Mach that were used on cluster systems on campus, prior to the switch to vendor UNIX. I know at least one person who had complete MacMach sources for the last version, but threw out the backup discs with the sources in the process of moving. So I know they exist. If nothing else, CMU did provide other sites their UX source package (eg UX42), which was the BSD single server environment. So I know that has to be out there, somewhere. — Chris Sent from my iPhone

5 years, 11 months

Software Tools Users Group Archive

by Warren Toomey

All, a while back Debbie Scherrer mailed me a copy of a "Software Tools Users Group" archive, and I've been sitting on my hands and forgetting to add it to the Unix Archive. It's now here: https://www.tuhs.org/Archive/Applications/Software_Tools/STUG_Archive/ The mirrors should pick it up soon. I've gzipped most of it as I'm getting a bit tight on space. Thanks to Debbie for the copy and to her and Clem for reminding me to pull my finger out :) Cheers, Warren

5 years, 11 months

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

by Norman Wilson

It's interesting that this comment about ptrace was written as early as 1980. Ron Minnich's reference to Plan 9 /proc misses the mark, though. By the time Plan 9 was written, System V already had /proc; see https://www.usenix.org/sites/default/files/usenix_winter91_faulkner.pdf And as the authors say, the idea actually dates back to Tom Killian's /proc in Research UNIX. I don't know when Tom's code first went live, but I first heard about it by seeing it in action on my first visit to Bell Labs in early 1984, and it was described in public in a talk at the Summer 1984 USENIX conference in Salt Lake City. I cannot quickly find an online copy of the corresponding paper; pointers appreciated. (Is there at least an online index of BTL CSTRs? The big search engine run by the place that still has some 1127 old-timers can't find that either.) As for ptrace itself, I heartily agree that /proc made it obsolete. So did everyone else in 1127 when I was there, but nobody wanted to update adb and sdb, which were big messes inside. So I did, attempting a substantial internal makeover of adb to ease making versions for different systems and even cross-versions, but just a quick hack for sdb. Once I'd done that and shipped the new adb and sdb binaries to all our machines, I removed the ptrace call from the kernel. It happened that in the Eighth (or was it Ninth by then? I'd have to dig out notes to find out) Edition manual, ptrace(2) was on two facing pages. To celebrate, I glued said pages together in the UNIX Room's copy of the manual. Would it were so easy to take out the trash today. Norman Wilson Toronto ON

5 years, 11 months

Re: [TUHS] Paper discussing Unix boot process?

by Pat Barron

The paper I am thinking of (gee, I wish I could remember any other details about it...) was *very* detailed and specific, and was hardware-specific to either the PDP-11 or VAX. It would not at all be applicable to Linux or any kind of modern OS. I am wondering if it is something in the Leffler et al book, I'll have to go back and review that. I'll have to find my copy of it first... --Pat.

5 years, 11 months

The Great NBN Out(r)age

by Dave Horsfall

A few bods have asked to see this, so... Actually, "extracted" would be better description than "redacted", but it's too late now; I could rename it and put in a CGI-redirect, but I'm too busy at the moment. ----- A redacted copy of my complaint to T$. www.horsfall.org/Telstra-comp-redact.rtf (yes, RTF; it was written on a Mac). Utterly inexcusable... Please share etc :-) -- Dave

5 years, 11 months

4.1c bsd ptrace man entry

by Doug McIlroy

Ptrace was short-lived at Research, appearing in 6th through 8th editions. /proc was introduced in the 8th. Norman axed it in the 9th. Norman wrote: nobody wanted to update adb and sdb, which were big messes inside. So I did ... Once I'd done that and shipped the new adb and sdb binaries to all our machines, I removed the ptrace call from the kernel. doug

5 years, 11 months

Re: [TUHS] 4.1c bsd ptrace man entry ("ptrace is unique and arcane")

by Kirk McKusick

> From: ron minnich <rminnich(a)gmail.com> > To: TUHS main list <tuhs(a)minnie.tuhs.org> > Subject: [TUHS] 4.1c bsd ptrace man entry ("ptrace is unique and > arcane") > Message-ID: > <CAP6exYJshbA5HxOJ_iM21Cs0Y4vGfLuFigXxh4WTeqbZreY8UA(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > 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 The manual pages were not yet under SCCS, so the best time gap that I can give you is that the above text was added between the release of 3BSD (Nov 1979) and 4.0BSD (Nov 1980). Most likely it was Bill Joy that made that change. Kirk McKusick

5 years, 11 months

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

5 years, 11 months

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

5 years, 11 months

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

5 years, 11 months

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

5 years, 11 months

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

5 years, 11 months

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

5 years, 11 months

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