< As far as I know, no x86 or 68xxx processor has ever had any degree of
< fault tolerance withing the chip, where it is needed. Getting it externa
Big time problem. Fault detection and instruction resequencing arent
there. That makes even a simple parity error in ram unmanageable.
< Most mainframes, even ones from the 1960s, have error checking throughou
< the entire system - even in the paths between the registers and ALU. If
I was told a story about an old 700 series where the cooling water for
the rooms chiller found a leak. The leak was in the hundreds of gallons
a minute rate. Oh, the 700 series is a vacuum tube machine so the under
floor cable troughs have data and power cables galore. Seems the machine
was still running fine when water started gushing out the bottom pannels
of the racks. All the interconnection cables and PS units were soaked and
it still ran! They shut down, fixed the pipe and dried the room and fired
everything back up no problem.
It was a general presumption that the machines due to the large number of
parts would be unreliable. The designs were robust to say the least and
in practice they were reliable, often far better than predicted.
< something goes wrong, like a gate goes into a "stuck at" condition, the
< redundant circuits and error correctors will jump into action and
< processing will not stop. Most machines will call home and have
Fault tolerence is an art in itself.
Allison
> Date: Fri, 23 Oct 1998 09:15:43 -0400 (EDT)
> From: Ethan Dicks <erd(a)infinet.com>
> To: classiccmp(a)u.washington.edu
> Subject: PDP-11/70 rescued!
> Message-ID: <199810231315.JAA24826(a)user2.infinet.com>
> MIME-Version: 1.0
> Content-Type: text/plain; charset=US-ASCII
> Content-Transfer-Encoding: 7bit
>
>
> The Computer Quonset Hut has its first aquisition - a pair of PDP-11/70's
> with peripherals.
Lucky guy.
> My biggest disappointment is that the CPUs have the corporate front panel,
> not the programmer's front panel. Anyone have a spare front panel they
> want to trade? ;-)
Actually the panel is better in some ways (except looks) than the 11/70
front panel.
I do prefer the DECdatasystem 570 (I think) 11/70 blue corporate
cabinet front panel for style. (The 11/74 used almost the same
front panel -- YES I did work with an 11/74 in DEC Princeton...
They did exist...
The "programmer's" front panel doesn't exist for the PDP11/70.
What you probably have is the 11/70 Remote Diagnostic Console
which allowed DEC to remotely diagnose the 11/70 (even when hung
in a microcode loop or power fail routine) from Colorado.
The front panel hooks to a microprocessor controlled card which interfaced
to a 300 or 1200/300 baud DEC or Racal Vadic modem (in auto answer
mode) when the key is in remote. Colorado would run a diagnostic chain,
examine the bus, read error logs etc.
>
> -ethan
>
> P.S. ISTR that PDP-11/70's and VAX-11/750's use the same hex-height 39-bit
> ECC memory boards. Is this true? I know that 750's had 256K and 1Mb
> boards (and eventually 4Mb boards), but every jump up required a new
> memory controller (and backplane wires ;-) What's the scoop on the 11/70?
They do use the same ones... I don't think the 11/70 supported more than
the 256k MS-11K boards, though.
Bill
ex-DEC Field Service...
If anyone else wants to bid on the list please get them to by 9:00 in the
morning (EST). I will respond with a copy of what I have to submit with
everyone's name on their group of items. Please check your section and part
# to be sure they are correct. To keep peace with the family I can't
respond anymore tonight.
Thanks
Dan
>Date: Sun, 25 Oct 1998 23:33:33 +0000 (GMT)
>Reply-To: classiccmp(a)u.washington.edu
>From: ard(a)p850ug1.demon.co.uk (Tony Duell)
>To: "Discussion re-collecting of classic computers"
<classiccmp(a)u.washington.edu>
>Subject: Re: TRS-80 Model I
>
>> When I was a kid I tho't that the keypad was incredibly lame because
it
>> didn't have a comma key. The only thing I would ever use it for
would have
>
>And I didn't like it because it didn't have A-F on it. Once a machine
>code programmer, always a machine code programmer and all that :-)
>
>That's why I never bought the keypad for my original Model 1.
>
>-tony
>
>
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
Speaking of A-F keys, does anyone here use any of the alternative
keyboards available for PC XTs and ATs? I'm curious if anyone has
ever seen the IrmaKey/3270 (IIRC) keyboards. They must have something
like 130 keys, but I have no idea how to program the macro keys.
Anyone know?
>
>> When I was a kid I tho't that the keypad was incredibly lame because
it
>> didn't have a comma key. The only thing I would ever use it for
would have
>
>And I didn't like it because it didn't have A-F on it. Once a machine
>code programmer, always a machine code programmer and all that :-)
>
>That's why I never bought the keypad for my original Model 1.
>
>-tony
>
>
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
There are some distributions that are sold for $50 but they usually include
book and phone support plus some sort of installation program
Francois
-------------------------------------------------------------
Visit the desperately in need of update
Sanctuary at: http://www.pclink.com/fauradon
-----Original Message-----
From: Jason Willgruber <roblwill(a)usaor.net>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Thursday, October 22, 1998 9:11 PM
Subject: Re: TRS-80 emulators
>I found that out. I was talking to the comp.tech guy at my school last
>week about getting a copy. He told me he'd be able to get me the new
>version for $50.
>
>Shows just how full of bull @#$% he is.
>
>Although he's the same guy that gave me a Tandy 1000TL because the "hard
>drive was shot". The power cable wasn't connected to it <g>
>--
> -Jason
>(roblwill(a)usaor.net)
> ICQ#-1730318
>
>----------
>> From: Sam Ismail <dastar(a)ncal.verio.com>
>> To: Discussion re-collecting of classic computers
><classiccmp(a)u.washington.edu>
>> Subject: Re: TRS-80 emulators
>> Date: Thursday, October 22, 1998 9:14 PM
>>
>> On Thu, 22 Oct 1998, Jason Willgruber wrote:
>>
>> > Actually, Tim Mann's TRS-80 page is where I got the disk images. I was
>> > going to get xtrs, but I don't have Linux (nor do I have the money to
>get
>> > it). I have an emulator that'll run in DOS, but won't recognise the
>file
>>
>> Linux? Money? Heheheh. What stone have you've been hiding under
>junior?
>>
>> LINUX IS FREEE, MAN!
>>
>> Sellam Alternate e-mail:
>dastar(a)siconic.com
>>
>---------------------------------------------------------------------------
-
>---
>> Ever onward.
>>
>> Coming in 1999: Vintage Computer Festival 3.0
>> See http://www.vintage.org/vcf for details!
>> [Last web site update: 09/21/98]
>>
>
< Anyone know how many of the TRS-80 model I computers were made without t
< numeric keypad? I remember a discussion a year or so ago where someone
< the UK was looking specifically for one without the keypad. In checkin
< through my collection, I only found one without the keypad, and am just
< curious.
Quite a few, I'd speculate over 50,000 for sure. The keypad was an
option that was very frequently added though so many originals were
keypadded, LII'd and 16k'd. It's rare to see a stock TRS80 that hasn't had
factory and customer mods.
Other common mods to the base console:
* Lovercase chars, (add a 2102 and a jumper, etch cut).
+++started as customer mod, then DEPOT repair mod.+++
* ^(CTRL) key so ^C and other characters could be done.
===Customer mod.
* Cassette load mod, small board with 4040 counter and a gate to
prevent cload hang under LII.
+++Depot repair, factory LII mod+++
* CPU clock speed up (bump the clock from 1.7mhz to 3.4mhz).
===customer mod.
Some companies also sold some of these mods as kits.
Allison
Folks - apparently this unit (may or may not have disks - the person
who posted about it is unsure) may be trashed if not spoken for by
monday...
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
| Unix Support Engineering Group | (home): mbg!world.std.com |
| Compaq Computer Corporation | addresses need '@' in place of '!' |
| 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ |
| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
| (603) 884 1055 | required." - mbg |
+--------------------------------+-------------------------------------+
OK, so it's not ten years old and therefore it isn't a classic.
But I use my ScanJet 3C to scan documents *about* classic computers,
and make them available on the web. For instance, the PDP-10 documentation
at
http://www.36bit.org/
So if anyone has an ADF (sheet feeder) that they're willing to sell,
please let me know. The one HP intended for it was the C2525A, but
I think the C2525B (for ScanJet 4C) and C6265A (for ScanJet 6100C)
will work as well. Also, the C1751A (for the ScanJet IIc & IIcx) might
work.
Thanks!
Eric
> Gradually I learned to use the pesky number keys at the top of the keyboard
> and ignored the numeric pad completely. Even today I ignore the numeric pads
> because they don't have comma keys on them.
What happens when you come across the One True Keyboard (VT100)
or its descendants, which do have a comma on the keyboard like
god intended?
There's even a DEC keyboard - the LK250 - which has a comma on
the keypad and works on PC-clones.
Tim.
