We're lucky here in Austin, TX to have the Goodwill Computer
Store. They often get old classics from people and sell them
for non-ePay-like prices. I was just there today, and they
had 3 Kaypro II machines for $20 per machine. On a scale of
1 to 10, they were quality 5, 6, & 7 or so. Alas, no software...
but it beats $50-$100 deals on ePay.
der Mouse wrote:
...
>Once, years ago, I was involved in building a designed-on-the-spot Qbus
>board.
Which raises a question I've been meaning to ask.
Has anyone made their own unibus boards? Is this fool-hearty?
I have half a mind to look over the "IDE for Soviet unibus" zip file I
found and make my own uniboard board with a modern day CPLD and IDE
interface.
How crazy is that?
I have 4-8 layer PCB's fabricated regularly and have a reasonable CAD
setup to do that, so design, layout & fabrication is not a problem, nor
is TTL design (heh, especially at unibus speeds :-) And I write VHDL for
CPLD's all the time and program them.
Seems like a 4 layer board with gold fingers would work - the few boards
I've handled seemed pretty thick, however. I'm guessing the thickness
needs to be correct.
I have not (yet) looked at a unibus card schematic - would be it hard to
create a bus master IDE interface?
Is a unibus controller a relatively straight forward TTL design ?
I should probably ask on the PUP list also, but I thougth I'd see if
anyone here has opinions.
And, if I did manage to create a realiable IDE interface, would anyone
else want one?
(I realize cost would be the overriding factor - believe it or not on
small runs like I do the PCB is by far the most expensive part)
-brad
> For me, at least, the hard part of designing a modern Qbus and/or
> Unibus interface would be what to select for bus drivers.
Well, for Qbus...there's an appendix in the KA630 document that's
titled "Q22-Bus Specification". Based on that:
>From the looks of it, for a driver you can use almost any
open-collector TTL output - at least, a quick look at the specs doesn't
reveal anything that stands out as incompatible.
The receivers are a bit more interesting. The spec says that their
threshold must be between 1.3 and 1.7 volts and that their high-level
input current must be no greater than 80?A; it fails to give any limits
on how much current they source into a low-level input, though there
surely must be such a limit. Are there any bus receiver chips that
have a reference-voltage pin, which could be connected to (say) 1.5V?
Basically, a bunch of specialized voltage comparators?
Personally, I'd be tempted to just use TTL and see if it works (LSTTL,
probably, since that sources less current into low-level inputs). But
of course "it works for me" isn't good enough if you're designing for
other people's use.
/~\ The ASCII der Mouse
\ / Ribbon Campaign
X Against HTML mouse(a)rodents.montreal.qc.ca
/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
Ethan Dicks <dickset(a)amanda.spole.gov> wrote:
> Yes, but some devices are not so old and _do_ use ASICs. There are some
> peripherals that came out at the same time as the 11/20 (~1970) that
> they are made up of several square feet of TTL/Linear chips.
Well, what I meant was that UNIBUS and Q-bus were designed to be implementable
without ASICS using only discrete logic, and the simpler devices were
implemented that way.
> Unibus? 8640, 8641, 340, 8881, DC013 (custom DEC chip)
> Qbus? DC003, DC004, DC005, DC006, DC010, 74LS240, 8837, 8838
>
> In other words, with few exceptions, *not* ordinary TTL chips (though ISTR
> one of their busses used hand-selected 7438s chosen for low (1uA?) leakage.
Hmm, 74LS240 for Q-bus? It's just a standard three-state TTL inverting buffer,
isn't it? For driver, receiver, or both?
> designed-as-such bus drivers/receivers from companies like
> National Semiconductor.
Does NS still make them?
MS
Quick question,
What would folks here be prepared to pay for this machine, particularly as
it's boxed and never been used? It went into the workshop to have a hard
drive fitted shortly after being bought in 1992 or thereabouts and for
whatever reason it sat on a shelf forever thereafter.
Or is the general concensus 'oh it's just a 386SX PC running DOS 5'
Pix at http://www.binarydinosaurs.co.uk/ebay/ibm/ibm.php
cheers
--
Adrian/Witchy
www.binarydinosaurs.co.uk - possibly the UK's biggest online computer museum
www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(
Hello Friend,
I actually have an old Qube box in my closet. The weird thing is that it doesn't work on any other cable systems, except the old qube system.
My unit used to work when we had the qube system. Once they shut off Qube, the unit no longer works.
I remember these things from when I was a kid, that is why I have kept it.
You know much about how they work? I would like to get this one to work. I have opened the unit, but see nothing wrong that would cause it to power up and then the display goes dead.
Glad to see someone has the same interest in these old things
Can anyone tell me what the BC20K is used on?
Thanks
Cynde
Cynde Moya, MLIS
Archives Cataloguer
Vulcan Inc.
www.vulcan.com
Office Tel. 206-223-4901
Mobile Tel. 206.369.3205
Fax. 206-223-4207
Hmm,
well u know what, the system programmers i guess use
the right side of their brain, while the admins use
their left.
i guess, as an admin, u need to look at individual
problems and try to solve them with a more logical and
rational approach
while, a programmer would have to use his creativity,
and intuition to be able to "design" programs/SWs.
and,
i'm neither of them, so no bias here!!!
what do u think, curt???
>
>
>
>Message: 1
Date: Fri, 16 Jan 2004 22:17:33 -0800
From: Ernest <ernestls(a)comcast.net>
Subject: System programmers vs. administrators
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk(a)classiccmp.org>
Message-ID: <1074320253.1586.16.camel@ernest>
Content-Type: text/plain
I was having a discussion with a friend earlier
tonight about
programming, and how I've never been the least bit
interested in
learning how to program -I'm convinced that I have a
mental block
against it, or something like that.
As the discussion progressed, we decided that there
are two types of
advanced computer users -system programmers and system
administrators.
That in itself is debatable but where our discussion
became bogged down
was when we tried to decide which user was left brain,
and which was
right brain.
We started by agreeing that programmers are artists,
while the
administrators are more scientific. But then, as we
talked, we decided
that you could make the same arguement for each side.
So, I thought I would throw the discussion out here,
and see what you
guys think. Assuming that there really are two types
of computer users
-programmers and administrators- which side is left
brain thinking, and
which is right brain thinking?
I pulled the following off some psycho-babble website:
Experimentation has shown that the two different
sides, or hemispheres,
of the brain are responsible for different manners of
thinking. The
following table illustrates the differences between
left-brain and
right-brain thinking:
Left Brain:
Logical
Sequential
Rational
Analytical
Objective
Looks at parts
Right Brain:
Random
Intuitive
Holistic
Synthesizing
Subjective
Looks at wholes
Most individuals have a distinct preference for one of
these styles of
thinking. Some, however, are more whole-brained and
equally adept at
both modes. In general, schools tend to favor
left-brain modes of
thinking, while downplaying the right-brain ones.
Left-brain scholastic
subjects focus on logical thinking, analysis, and
accuracy.
Right-brained subjects, on the other hand, focus on
aesthetics,
feeling,
and creativity.
------------------------------
Message: 2
Date: Sat, 17 Jan 2004 12:19:54 -0500
From: "Curt vendel" <curt(a)atarimuseum.com>
Subject: Re: Re: Apple 'Star Trek'?
To: <freddyboomboom(a)comcast.net>, "General Discussion:
On-Topic and
Off-Topic Posts" <cctalk(a)classiccmp.org>
Message-ID: <000601c3dd1e$211f6990$1a02a8c0@starship1>
Content-Type: text/plain; charset="iso-8859-1"
Hmmmm....
D/L'ing now... curious to check this out :-)
I have a Mac OS X 10.2 Server running in my office, so
I'm curious to
see
how these interact...
Curt
________________________________________________________________________
Yahoo! Messenger - Communicate instantly..."Ping"
your friends today! Download Messenger Now
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Hi folks,
Has anyone got a spare 2.5mm 12V DC power socket that's PCB mounted? The one
I'm replacing looks exactly like these:
http://tinyurl.com/2mhkrhttp://tinyurl.com/3gtau
I can only get 'em in packs of 10 and I don't really want to buy 10!
Cheers all!
--
Adrian/Witchy
www.binarydinosaurs.co.uk - possibly the UK's biggest online computer museum
www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(
