At 21:27 29/03/99 -0800, Sellam Ismail wrote:
>On Mon, 29 Mar 1999, Bruce Lane wrote:
>
>> Actually, ASR-33's ran at 110 Baud rather than BPS.
>
>Same difference.
No, Baud and BPS are different. Baud is the number of signalling changes
per second. Normally, each signal change gives one bit and then Baud ==
BPS, but if you encode more than one bit per signal change then they are
not the same. This is easily achieved if you have different voltages mean
different values. For example, if you use -10V, -5V, 5V and 10V to encode
0, 1, 2 and 3 then the bit rate is twice the baud rate.
Huw Davies | e-mail: Huw.Davies(a)latrobe.edu.au
Information Technology Services | Phone: +61 3 9479 1550 Fax: +61 3 9479
1999
La Trobe University | "If God had wanted soccer played in the
Melbourne Australia 3083 | air, the sky would be painted green"
> What were they? I assume one was the termination switch.
Well, I'm home now and I realize that I was using a Panasonic
TR-120, not my Amdek (I wonder where that's buried?). The
only switch that makes a difference is labled:
Hi-Z
75 <ohm symbol>
It looks good in the "Hi-Z" position although I can now see
that if I turn up the brightness and contrast all the way I can
just make out the display in the 75ohm position. I've just
spent a couple of minutes fooling with the pot shaft sticking
out of the back panel and, sure enough, it makes a difference
in the behavior of the color regions that the color test program
displays. I'll try it on my "good" TV in a little while.
Your commment below about production is true enough, but such arrangements
built sloppily will suffer from day-to-day use in an environment where cards
are being move about. I'd say one should glue the part down and keep the
haywires as short as possible.
By the way, in the aerospace industry, 25 pieces is a long run. Almost
everything is built in small quantity because you're only building one or
two of those rockets or satellites, and by the time you do it again, the
design requirements have changed.
Dick
-----Original Message-----
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, March 31, 1999 5:40 PM
Subject: Re: Kits vs ready-made (was RE: Rebirth of IMSAI)
>>
>> The classic example is an IC suspended over a PCB by means of the little
>> pieces of #40 wire which connect it to the circuit. They're not always a
>
>Well I'd probably stick the IC down to something, and use thicker wire
>(stander wire-wrap wire is quite good for this), but I really don't see
>the problem with doing this for experimental/prototype circuits, even
>ones that are going to be used. I've done it many times and it's never
>given any trouble.
>
>> terrible way to do things, and they've even been blessed by the analog
>> weenies at NatSemi, but their use in modifying or even building circuits
>> intended for some practical use is an abomination. Experimentation,
well,
>> OK, but to use it repeatedly? . . .
>
>Well, obviously you don't want to use it in production (far too
>labour-intensive), but that should be the only problem if it's properly
done.
>
>-tony
>
take a look below, please.
Dick
-----Original Message-----
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, March 31, 1999 5:40 PM
Subject: Re: Kits vs ready-made (was RE: Rebirth of IMSAI)
>>
>> Unfortunately, in today's climate ("NOTHING's MY fault!") people buy a
kit
>
>Yes, that attitude is _very_ annoying....
>
>> A degree in engineering isn't sufficient qualification, either. Some of
the
>> crappiest work I ever saw while in the aerospace industry, was by fairly
>
>Oh, don't get me started on that. I have no engineering qualifications at
>all, but, even if I say so myself, I could out-design, out-construct, and
>plain out-hack a number of people with degrees in engineering that I met...
>
>A few classic cases that spring to mind :
>
>One chap said 'There are no 362.8 Ohm resistors in the box'. I said I
>wasn't supprised and asked him what on earth he wanted it for. The
>answer : An LED current limiting resistor. That was the value that the
>formula had given, so that was obviously the value he needed.
>
>Another person had problems with a simple RC low-pass filter. And he
>certainly had no idea about making sensible approximations.
>
>The only problem that comes from this is that mangement-droids seem to
>think that qualifications imply competence/knowledge. So I'm stuck unable
>to get a job :-(
>
>> senior engineers. The excuse was that "it's not a deliverable," but
often
>> the shoddy technique (air-wires, etc) made for problems which couldn't
>
>If that's another name for dead-bugging, there's nothing wrong with it if
>used correctly. In fact IMHO it's the _only_ way to prototype
>high-frequency circuits with any sort of reliability
I have used dead-bug patches quite a few times myself. More specifically,
dead-bugging is typically gluing or taping an IC onto another's back and
running wires between it and the appropriate points in the circuit. I don't
mean that, so much, but using multiple feet of #40 magnet wire with the
shellac sanded or scraped off and having the scabbed-in IC floating on a web
of wires 3" above the board . . . ???
>And if you trust simulations to correclty predict the behaviour of even
>simple circuits, well, have I got some storys to tell you...
>
Yes, I have a few, too, but . . . Careful now . . . I've spend thousands of
hours in front of a big tube waiting for a simulation. I am a big believer,
and believe further, that anyone who claims that simulators don't have a
place, as some old-timers do, just hasn't investigated sufficiently.
>
>-tony
>
>I have an 7 KBaud modem over here so, where's your stick ?
>(Hint: server side of an 56K analouge dial in :)
>(small print: the calculation can be done different :)
As I understand it, a baud is 'number of signal changes per
second'. If you use an encoding method which requires a signal
change for each bit, then 9600baud = 9600bps. Another encoding
scheme might only require 4800baud (4800 signal changes) to get
9600 bps across the wire.
In this case, it sounds like your modem uses a scheme which
somehow gets 4 bits across the wire per signal change, so
7Kbaud (7000 signal changes per second) gets across 56Kbps
(56000 bits per second).
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 |
+--------------------------------+-------------------------------------+
Okay, I own a computer so of course to everyone who doesn't I'm some
kind of expert (not).
So the other day this guy brings me this 256k Wang, wants me to set
it up for him. Set up to do what? Alright maybe I may have some old DOS
stuff a wordprocessor, spreadsheet, hell maybe I even got a pong game still
laying around. My problem is how do I write to this thing?
Its got one of those old floppy drives with the lever and all (never
used them I was running a Mac before IBM saw the light). The hard drive is
>from the stone age (is this SCSI compatible?) And the mother of all boards
with connections for a network possibly? Probably a mainframe Yuk. Anybody
ever own one of these things? Can anything be salvaged? Is this just an
overgrown typewriter? How am I going to write to this thing without
destroying my computer? Help Help Help...
Here's some numbers: cpu 256kb, two PMO30-b 128k Memory expansion, PMO08 c.g.I (monitor controller?), pm02/022-b Winchester controller,Seagate HD, and of course the standard Wang kb and monitor (RGB I think they called them you know green just green). Everything works even has some old data base software still on it.
FrednLenny(a)compuage.com
please see imbedded comments below.
regards,
Dick
-----Original Message-----
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, March 31, 1999 4:49 PM
Subject: Re: Kits vs ready-made (was RE: Rebirth of IMSAI)
>> The kit, of course, has to be properly documented. In today's ready-made
>> environment, little documentation accompanies a product, though even
that's
>> not often used. Today, the kit would be offered not so people can enjoy
>
>The reason why the documentation is 'seldom used' is that it's useless.
>Some of the manuals I've seen for modern computer products would insult
>anybody with more than 2 working braincells...
>
You are on the money there! There's so much simplistic fluff, yet no meat.
>
>> You're certainly right about the cost of documentation. That's why it's
>> hard to recommend LINUX and some of the rather excellent pieces of
software
>> work which have been done in conjunction with it. The documentation is
>> generally quite poor, and always several generations out of date.
>
>Eh? I'd much rather do something obscure with Linux given a standard
>distribution and _any_ linux book (of _your_ choice if you like) than do
>something simpler with, say, Windows given _every_ published book and SDK.
>
I've never been a promoter of heavily commercialized software, nor have I
believed in the things the MS is doing with its software, e.g. the flight
simulator built into EXCEL, but I've had VERY little trouble with '95. I've
had to read very little documentation about the OS. Likewise, NT, though
you can leave out the "VERY" with respect to it. '95 has always worked
exactly as I expected and although there are a few things I can't explain
about it, THIS very machine on which I normally do my communications, has
been up continuously since June of '95 when I loaded a BETA on it and I've
continuously updated it to where it's running OSR2 dated about a year ago,
and the only times it's been down habe been due to hardware upgrades or
hardware faults.
At the POP, there are three LINUX boxes running satisfactorily for over a
year, as terminal server, among other things, and one really can't complain.
I just complained because of the documentation maze, which is certainly in
ample evidence.
>
That would be really nice if there were a genuinely "standard" distribution.
Perhaps the current trend toward increased commercialization will lead to
that. I've never claimed to be a software expert, though I've been coding
for a living, on and off, since about 1965. I've never managed to get even
one instant of useful work for myself out of LINUX, even though I've gone
through numerous releases and several distributions. The documents are
almost always so far out of sync as to be useless and are NEVER sufficiently
correct to instill confidence in one unfamiliar with its inards. I suppose
one who knows exactly what he's looking for will find it, but as a foreigner
to LINUX, I didn't find the dozens of GBytes of doc files, often
conflicting, to be much help.
Example: Simple tasks like installing LINUX on an ESDI drive larger than
what the BIOS supports are not supported by any written documents, though
the writing about other drive types (not SCSI) may shed light on it, though
the doc's about EIDE are also conflicting. These are made hopelessly
complicated by the various often self-contradictory attempts at describing
what's to be done. I finally gave up on the half-dozen or so conflicting
write-ups I had and worked the details out with a fellow in Germany who,
though his English was limited, as is my German-"computerese," managed to
convince me that it was really quite straightforward.
My goal, however, was to use a LINUX box rather than an NT box in order to
provide a TCP/IP gateway to share the modem, replace my NETWARE server, and
process FAX traffic over the LAN as well. Though it claimed (announced) to
have loaded all the appropriate modules, it didn't show any signs of doing
what I wanted. Now, there was no indication that it wouldn't. . .
>
>Linux documentation, at least the stuff I've worked with is an order of
>magnitude better than that of most other OS's (although some DEC docs
>kits are even better). For one thing, Linux documentation is pretty
>complete (it doesn't normally miss out stuff that might 'confuse the
>user'). And if you have problems, you cd /usr/src/linux and dig around :-)
>
Yes, you can and must do that, but it's like having a system of 25 equations
in 12 unknowns. The solution is in there somewhere, but which one?
>
>And yes, I do consider source code to be possible documentation for a
>piece of software, just as I consider a schematic to be possible
>documentation for a piece of hardware.
It's true that source code SHOULD be part of the documentation. In too many
cases it's ALL the documentation, and though the code was modified, the
comments weren't kept in sync. That's where it's a real pain when they
leave out key words like NOT.
>
>-tony
>
Hi all,
Because i feel so lonely here in Denver, i got the idea of collecting a
list of the listmembers. I simply want to see, in what areas you can meet
people an what they collecting.
I think a list with only a zip code, name, which computer/other stuff you
collect should do it.
What do you think ?
cheers,
emanuel
The Timonium Hamfest had an excellent turnout. Tailgating spots were
sold out. I spent half the day there, purchasing the following equipment:
2 Bell & Howell Apple II+'s. Both are in rather poor condition, the one
even has an ordinairy II+ keyboard and no power supply. I'm thinking
about putting a IIgs mb in it for a "Stealth GS". The other is missing
the '0' key. Anybody have one they'd like to part with?
6 NEC Ultralite Notebooks. Does anybody know what the power adapter for
these is like? They have interesting connectors. I'll probably just
hook the power up to the battery connectors. Two of the notebooks are
labeled "lights up, but won't boot." If anybody wants one of these most
likely borken units before I start to fool around with them, the price is
$10.
2 Compaq Portables. I'll sell one of them for $25, if anybody's
interested. I just need to test it first.
6 IBM PC Convertibles. Last summer I purchased about a dozen IBM PC
Convertible AC adapters at a hamfest for $1, knowing that some day I'd
come across a pile of Convertibles at a Hamfest, lacking power supplies.
Well wouldn't you know there was a stack of Convertibles at the Timonium
show - and not one of them had an AC adapter. If anybody's interested in
one of these, figure about $25.
IBM 5155
Compaq Portable III
Grid Gridlite
IBM 3127
Apple IIgs-style ADB keyboard - finally!
I know next to nothing about the following units, and I'm not sure if any
of them are ten years old. If somebody could give me some details on
them (espeically on the SparcServer 470), I'd appreciate it.
HP Apollo 400 ("upgraded to 439")
Sun SparcServer 470
Sun SparcStation IPX
Sun SparcStation ELC
DecServer 200/MC (I have two - any interest?)
Anbody know where I can get kb, mice, and monitors for these systems?
What I missed:
A Xycon computer, complete with two external 8" drives and keyboard.
Three all-in-one "business" computers, with 5.25" drives (I forget the
name, but they sure looked interesting)
A PDP-11/44.
Would the offending party identify himself? :-)
Anyone have any idea what was/is the best bus design?
I'm thinking a stripped down Z-bus (without the M1 signal and etc). What
else should be on a bus besides:
ADDRESS
DATA
RD/WR
MEM/IO
BUS REQ
BUS ACK
INT
INT ACK
WAIT
HALT
RESET
CLOCK
----------------------------------------
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Move up to a REAL OS...
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