15 Jun
2009
15 Jun
'09
2:39 p.m.
Tony Duell wrote:
And that's fine, Tony. I agree, and I share your affinity for this.
But I don't have the resources to indulge my hobbyist desires in this
field. I've recently been rudely uprooted, and lost my entire
electronics shop.
This isn't a specifically Brit term. I am refering to the 'bus grant' and
'non processor grant' signals on a DEC Unibus (or Q-bus) backplane. The
former are used for interrupts, the latter for DMA transfers.
Oh. Okay. Thanks. I've not heard it expressed that way.
Yes, it's possible. No, I've not seen it. Hey, there might be
something you'd enjoy doing in software.... <Grin>
Oh, no, that doesn't sound crazy. I share your interest. I just don't
always want to HAVE TO solve problems before I can accomplish
something. My current set-up is much more reliable than the IMSAI
hardware, mostly because of the 2102 memory. Long ago, I got rid of
that, and replaced it with 6116-based memory, and life got much easier
in the CP/M world.
All I'm saying is that it is much easier to expand the hobby of the
software side of classic computing. Also, about half the people don't
have to spend ANYTHING to start it.
Warren
I am also interested in old clocks and old (valve)
radios, and none of
the magazies devoted to collecting/restoring those seem to think there's
much a problem. The 'pool' of both of those items is surely finite too.
It's just a matter of degree. I suspect there were very many more valve
radios produced than classic computers, probably a couple orders of
magnitude. However, even those will be, for all practical purposes,
gone in time. While it won't have any effect on you or me, run the
clock ahead a hundred years... and very little of either will remain.
I guess if you want a particular model of classic
computer you are going
to have problems finding it, but there seem to be plenty of classics out
there at the momnet if you'll work on just about anything.
True... but, even WAY old classic computers are less than 50 years
old. I mean, is there even someone out there with an IBM 360?
No it's not free. Even if the emulator software is
free, the machine to
run it on is not. Period. You have, alas, touched a nerve here, I object
to this attitude that 'everybody' has a PC/cellphone/MP3 player/digital
camera. I don't, nor do many people I know.
You've got to look at the numbers... When the IBM PC was first
released, fewer than 5% of homes in the U.S. had computers. The number
went over 50% in 2000, and has not looked back. Do the math. 10 times
as many people have computers now, as did then. If everybody wanted a
classic computer, even a personal classic, there aren't enough to go around.
More than half of current households have a PC. What percentage have
o'scopes? Quite small, I'm sure. The chances of a person being able to
run an emulator are significantly better than their chances of being
able to work on old hardware and fix it. And, for those who do not have
the requisites, what is the cost? What's the cost of an old PC
machine? I see them all the time for less than $100. What's the cost
of an electronics shop? I spent thousands, and was still lacking many
items.
It's clearly true that not EVERYBODY has any of the items you list.
However, most people have access to most of them, and the percentages
keep rising.
In fact for me to be able to run any of the emulators
at a sensible speed
it would cost me more than I've spent on any one of my classic computers.
OK, I was lucky and got many of them before they became collectable, but
I've bought interesting machines (to me) in the last year or so for a lot
less than I'd spend on a machine to run an emulator.
I think you're assuming you need a new machine to run an emulator....
Not true! A five-year-old PC is quite cheap. Not useful in the "speed
demon" sense, and not yet "classic," they sit at the nadir of their
value. Fish THERE for cost effectiveness.
this branch of
the hobby, I have the money and space to take it as far
as I want. I like that.
If you enjoy running old software on emulators, great. I am not going to
say you're wrong to do so (because you're not) .But I'd rather grab
'scope and soldering iron and dive into a 1970's TTL-built CPU...
[...]
Yes, but the emulator won't allow you to stick in
a KM11, put one of the
CPU boards on an extender and probe arround will single-stepping at the
clock cycle level. You won't have the fun of replacing a disk head and
doing the alingment. You won't have to chase grants up and down the
backplane.
I thought I was up on Brit tech-speak, but "grants" is one I
don't
know. What are "grants?"
True enough,
Tony, but with the right emulator, I CAN single step, and
Aingle-step instructiosn, possibly. But single-step the CPU microcode?
And at a clock cycle level (even lower than microcode)? I've not seen an
emulator thart does that (it's possible, of course).
examine
register contents, and so on. And I don't HAVE to repair the
hardware to keep it going. I used to maintain a mailing list on a
Crazy as it sounds, I like finding hardware faults. It's like solving
puzzles...