test-drb May 2016

test-drb@ccmp.vtda.org

202 participants
259 discussions

When did Memory- and IO Protection Emerge (Esp. in Minis)?

by erik＠baigar.de

Dear Experts, during discussing the Rolms I came accross the following question: What was the first (Minicomputer) architecture which offered memory- and IO protection? I'd define the minimum requirements as: - Existence of a superuser mode (Rolm calls this Executive mode) - Existence of a user mode (With at least two users, Rolm offers 4) - In superuser mode, IO and memory protection for each user can be set up individually. - Any access violation is trapped and handeled by superuser code. - Of course commands for mode switching and setting up the memory and IO ranges must exist. I have got a real machine (Rolm 1602) having this implemented and dating from 1975. A document on this "Access Protection Module" as Rolm calls it also is dated 1975. It consists of a microcode module which realizes an extension of the 16 bit Nova instruction set and an additinoal CPU module, taking care of the new modes and supervising the IO- and memory accesses. My question is not regarding virtual memory memory, but regarding protection (IO and memory) to ensure capsulation of indivitual processes - not necessarily for multi user environments but e.g. for safety critical applications... Probably OS/2 in 1987 was one of the first home computer OSes to support memory protection (how about IO protection?), BSD on some Digital PDP-* was earlier (1977?) but still after the 1602. Any hints out there on other "Mini" architectures of that era having someting similar? Erik.

8 years, 2 months

PDP-11/05 microcode dump?

by jnc＠mercury.lcs.mit.edu

> From: Mattis Lind > Now I am convinced that if I program a new A04A2 PROM the machine > should behave much better. Indeed! I have annotated the PROM tables on the Computer History wiki page with the function of each, and that PROM is the high part of the 'next microinstruction' field, so if it's bad, the computer will be acting very strangely indeed! :-) > The failing chip was yet another NS chip in plastic Can you see the type? I'd like to add to the page lists of all the alternate chip types DEC used in place of the Intersil chips specified in the drawings. >> the 'F' etch rev has one less PROM chip than the 'E' etch rev, but I >> suspect .. that it's not a micro-program chip, though My guess was correct; the missing chip is the one I called "Internal interrupt acknowledge"; it was replaced with a 74154 4->16 demux. Noel

8 years, 2 months

Free to a Good Home - VAX 4000-105A in the UK

by robert.jarratt＠ntlworld.com

This one has a failed BCACHE, but I am told it will still boot and run VMS, albeit slowly. I have not tried this myself, but I have verified that it boots to the console. It is in a BA42B enclosure (i.e. desktop not rackmount). Is there any interest or should I just take out the bits I want from it and then throw it away? It is in Manchester, UK. I do occasionally travel to the East Midlands and to the Reading area though. Not keen on shipping it, but will do so if it means not throwing it away. The machine is free, any shipping would have to be paid for of course. Regards Rob

8 years, 2 months

AlphaStation 200 NVRAM Problem

by robert.jarratt＠ntlworld.com

I want to read the DROM chip with my programmer, but I can't ID the chip. Does anyone know what kind it is? It is in a PLCC32 package and the label on it is: 369E7 AYOMA 49/95 I am sure at least some of that is DEC stuff, unrelated to the type of chip. However, none of those parts of the label seem to correspond to any EPROM I can find. My programmer's software has an auto detect feature, but that also failed to ID the chip. I don't really want to remove the label if I can avoid it. The underside is marked 76394-23 Singapore C4 522 (might be 322) 512X None of these appear to match anything either. Any ideas what it might be? Thanks Rob

8 years, 2 months

PDP-11/05 microcode dump?

by jnc＠mercury.lcs.mit.edu

> From: Mattis Lind > Has anyone dumped the microcode of the PDP-11/05? > ... > When tracing the microprogram flow it looks very suspicious. Comparing > the same sequence with a better working pair reveal a few differences. > All these can be narrowed down to one single PROM chip. Josh had an 11/05 that had a uROM fail, and he had to blow a new one (IIRC he sent in a report, it's in the list archive). I'm not sure if it's the same one as the one you need, but if his post doesn't give the chip ID, no doubt he can let us know. > There are microcode listings in the manual but they need to be treated > to get into a dump. Which is exactly what Josh did. Speaking of which, is there any chance we can get those machine-readable listings online? I can host them with my other DEC material, and I can also put them in the Computer History wiki. Noel

8 years, 2 months

Facit 4070 to PC interface

by tsw-cc＠johana.com

Request for information about a Facit 4070. Yes, it can be hooked up to a parallel port interface. It takes a single 74LS00 chip to generate the proper signals, and the ACK signals. I did it in a simple jumper wire block (it has a male and female connector along with a jumper field. At the moment I have lost my documentation, but I have a working unit ready to be dissected to produce the proper diagram (it may take a while). I have connected it to a "real" and a USB parallel port and used direct writes to the parallel port device under Linux with no modification. Also if you are interested, I have a program that sends out block letters to be punched on the tape (along with leader). The letters are 5x7 and the 8th is the descender for lower case letters. The various docs for the 4070 are on Bitsavers, and you want to be sure that the "option" board just has jumpers on it (as it comes from the factory).

8 years, 2 months

Memory and I/O protection on the 940

by mark.kahrs＠gmail.com

Al mentioned the 940 so I thought I would fill in the details: Lichtenberger and Pirtle extended the hardware to include a page map: 14 bits of VA was divided into 3 bits of page # and 11 bits of offset. The 8 pages were held in 2 x 24 bit words divided into a 8 x 6 bit page numbers. The high order bit of the mapped page number served as the Read Only bit. This meant that "subsystems" (a.k.a. applications) could be shared between users. Additionally, the instruction set was protected against users with specific prohibition against using the I/O instructions. This was described in FJCC 1965 with modifications done in 1964.

8 years, 2 months

PDP-11/05 microcode dump?

by jnc＠mercury.lcs.mit.edu

> From: William Degnan >> I would need a dump of .. at least A04A2 / E102 on the Control board. > Can you clarify? Is this a typo? No, there are two different major versions of the M7261 Control board; see http://gunkies.org/wiki/PDP-11/05#CPU_board_versions A04A2 is inded E102 on the later major version of the board; on the earlier version (prints for that version are in the GT40 prints online, pg. 162 and on) A04A2 is E92. Speaking of the two major versions, though, I wonder if the ucode in the two versions is identical? The uROM chip numbers should give it, (if they are the same on both versions, albeit in different locations on the board), but I have yet to check. Does anyone happen to know? Noel

8 years, 2 months

Pics of a FASTRAND and other fun things.

by pontus＠Update.UU.SE

Hi I follow a facebook group of Swedes mainly interrested in micros of the 80:ies. While that is fun in it's own right I recently decided to ask what "heavy iron", if any, the members might possess. I was pleasantly surprised of what surfaced. I though that some of you might also enjoy this, so here is the pick of the litter (reproduced with permission). A GE/PAC 4060 Drum memory, from person A: http://www.update.uu.se/~pontus/slask/fb_comphist/ge_pac_4060_drum_1.jpg http://www.update.uu.se/~pontus/slask/fb_comphist/ge_pac_4060_drum_2.jpg Univac artefacts, from person B: http://www.update.uu.se/~pontus/slask/fb_comphist/FASTRAND_III.jpg http://www.update.uu.se/~pontus/slask/fb_comphist/FASTRAND_III_2.jpg http://www.update.uu.se/~pontus/slask/fb_comphist/FASTRAND_III_3.jpg http://www.update.uu.se/~pontus/slask/fb_comphist/1701_memory.jpg http://www.update.uu.se/~pontus/slask/fb_comphist/saab_univac_poster.jpg The following is the teletype that I believe must come from a UNIVAC 418 or 1106 console desk. It looks like a model 28. Can anyone confirm? http://www.update.uu.se/~pontus/slask/fb_comphist/teletypeXX.jpg http://www.update.uu.se/~pontus/slask/fb_comphist/418-II.jpg DIAB racks from person C, probably only interesting for Swedish unix buffs. DIAB machines are somewhat uncommon and the rack versions even more so. http://www.update.uu.se/~pontus/slask/fb_comphist/diab_racks.jpg Have a nice weekend, Pontus.

8 years, 2 months

The Radio Boys and Girls: Radio, Telegraph, Telephone and Wireless Adventures f

by COURYHOUSE＠aol.com

Before there were books of kids doing thins with computers there was: The Radio Boys and Girls: Radio, Telegraph, Telephone and Wireless Adventures for Juvenile Readers, 1890-1945 - A View Though Literature By Mike Adams A Review By Ed Sharpe Director and Lead Archivist for Southwest Museum of Engineering Communications and Computation Glendale Daily Planet / KKAT-IPTV Read At http://glendaledailyplanet.com/the-radio-boys-and-girls-radio-telegraph-tele phone-and-wireless-adventu-p570-154.htm

8 years, 2 months

← Newer
1
...
19
20
21
22
23
24
25
26
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb May 2016