Sorry if this thread is old hat now - I've been having a hard time keeping up
with the volume of traffic here recently.
> Kits are often more costly than ready-built products because kit builders
> fix their mistakes, while you can't expect the user of ready-made stuff to
> fix your mistakes. Tech support is a necessity, yet most kit builders don't
> need it. Tech support is what costs when you're selling a ready-built
> product for the home computer market.
This is strange. You are saying: Tech support is what costs. Kits don't need
so much. Therefore kits are more expensive. ???
I claim the other way around. Most kit suppliers have to spend _more_ on
technical support because they have to help people who try kits too hard for
them and expect the supplier to sort out their mistakes.
Kits generally have shorter production runs than complete units, hence less
quantity discount / economy of scale.
Finally, kits are generally better documented than complete units sold as such.
And documentation costs a lot!
Philip.
On Mon, 29 Mar 1999, Geoff Roberts wrote:
>I hope it goes as well for me. (But it probably won't).
To which Max replied:
> If you expect to mess up, you'll probably find some way to do just that...
> --Max Eskin (max82(a)surfree.com)
In contrast, if you *don't* expect to mess up, you *definitely* will.
The tricky bit is to foresee exactly what your mess-up will be, and
prevent it.
Bill.
> On Tue, 23 Mar 1999, Max Eskin wrote:
>
>> Perhaps, have the machines run the demos that they were running in the
>> showrooms?
[...]
> Does anyone remember what the VIC-20 was usually up to in department store
> displays?
>
> PETs?
Pets I do remember. At least, the 8032. There was a screen that said in large
letters "80 COLUMNS" which was manipulated in various ways using the (new)
8000-series ROM routines for scrolling in various directions, defining a virtual
screen smaller than the real one, etc.
Philip.
>The rightmost slots in a DD11-PK (11/34 CPU backplane) are special. No
>way is slot 2 an MUD slot, for example. We are talking about the same
>backplane, I trust...
I found a couple of pages in the printset which show the board order
for some standard configurations (11/04, 11/34 and 11/34a), and one
of the pages clearly shows that slot 2 is a MUD slot. It just so happens
that the second board of the CPU goes in it. I guess the printset
could be wrong... but I'd like to believe I can trust it.
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 |
+--------------------------------+-------------------------------------+
Because the Opcode fetch cycle was shorter than other memory cycles, it was
common practice to use M1* to insert a wait state. This added an extra
clock tick to the length of the cycle, making it almost as long as normal
memory cycles. That practice also set back DRAM design by a mite. It would
have been smarter for the chip designers to cough up the MREQ* a bit sooner
during M1* in order to make it easier to distinguish between opcode fetch
cycles and interrupt acknowledg cycles. Hindsight is always 20-20 . . .
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 2:09 PM
Subject: Re: Z-80 M1?
>[Z80 M1 signal]
>
>> M1 signals the start of an instruction fetch or an interrupt cycle start.
>> It's machine status to differentiate a opcode fetch from a data read or
>> write. it serves other uses especially with the Z80 periperal chips.
>
>Sure, and if asserted along with IORQ/ it signals an interrupt
>acknowledge cycle (Which is logical, as at least in Mode 0, it is going
>to execute an instruction fetched from the peripheral chip).
>
>But I guess the question is _why_ would external logic need to know that
>a memory cycle was an instruction fetch rather than a data read. In some
>ways signalling a memory cycle that wasn't addressed from the PC would be
>more use.
>
>I suppose some of the peripheral chips recognised things like RETI
>instructions so they'd need to know that the appropriate bytes were being
>fetched as instructions and not data. Is that the only common use, though?
>
>-tony
>
On Sun, 28 Mar 1999, Derek Peschel <dpeschel(a)u.washington.edu> wrote:
] Periodically I swing by Surplus Property here. It's very disappointing;
... mucho deletia ...
Sounds like certain other surplus shops I know of. If it is
publically accessible, make sure to periodically check their
dumpster. And it is probably a good idea not to be obvious
about it; even if it is legal, any adminstrators getting wind
of it will imagine injury lawsuits, and put up barbed wire
and security guards.
Cheers,
Bill.
I recently acquired, and now have up and running,
an OSI C4PMF. It has composite video output, 16
color. I have a mono composite monitor and the
display is OK, some of the colors show up as grays
(well, greens actually) but others show up in a
sort of flickering effect. Video signals is one
area in which my ignorance shines! I first tried
to plug it straight into the 'video in' RCA jack on
my color TV. It was trying to do something, but no
dice. Next I RTFM. Says I need an RF Modulator.
"I've got one of those" I think. I dig through my
box of Timex-Sinclairs (BTW has just about everybody
on this list, when they told their friends and family
that they were collecting old computers, been given
piles of TS-1000s?). I find one of those little
silver boxes and hook it up. One problem, the box
has the old 2-wire TV antenna cable on it, the TV
has coaxial antenna in, but I dig through my junk
box and find a converter. Switch the TV to channel 3
and... still no good. Pop the back off the little
silver box... it looks like it's just a switch. No
other components in the box except for a couple of
torids that the wire loops around. Is this box an
RF Modulator? Is there some simple circut I can build
>from Radio Shack parts that would convert to (NTSC I
guess?) 'video in' on my TV.
Thanks,
Bill Sudbrink
I took the time to copy Colan's address and was planning on replacing the list
address with Colan's and the rest is history. I'm really sorry.
----------------------------------------------------------------------------
-------------------------------
Kevin Stumpf * Unusual systems * www.unusual.on.ca
+1.519.744.2900 * EST/EDT GMT - 5
Collector - Commercial Mainframes & Minicomputers from
the 50s, 60s, & 70s and control panels and consoles.
Author & Publisher - A Guide to Collecting Computers &
Computer Collectibles * ISBN 0-9684244-0-6
.
Hello Brian,
>
>
>I've raised the idea with Larry about a get together sometime on the
>weekend after easter, lunch on me.
>
>
>Colan
>
>
Please excuse me too, but the timing is incredible. I'd like to have a BBQ
in Kitchener
in June. Not an organizational event, but just a social gathering of
computer collectors.
I was thinking of supplying the propane and iced tea and everyone
contributing a few
dollars for burgers, etc. We could meet around noon on a sunny Saturday
afternoon
in June and be bidding each other farewell by supper time. My "ware"house is
large
enough and convenient enough to hold the gathering.
Please bounce that idea around also. What does t3c stand for?
Yours in good faith.
I don't remember what my point was or where the original notion that kits
often cost more that ready-made, except that if one sells kits, the folks
who buy them usually are competent and capable of fixing their mistakes. If
you sell both kits and ready-made, not only do you have to offer tech
support to the buyers of the ready-made product because you attract a wholly
less competent buyer, but a goodly share of your kit buyers are peoplenot
otherwise competent hoping to save a few dollars by messing the kit up and
then having your tech support people nursemaid them through the repair. I
remember that the kits I bought were accompanied by a parts inventory, an
assembly drawing, a schematic, and an extensive set of assembly and checkout
instructions, none of which accompanies today's PC-oriented products.
You're lucky if you can figure out from any of the paperwork, who built the
product and whom to call if you have a problem.
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
building it, though that's an added benefit for those who really do enjoy
it, but rather to circumvent FCC restrictions if that's still possible. The
FCC testing would keep almost any of the products of this sort with which I
became familiar back in the '70's off the market, first because they would
knock out TV reception for a considerable distance, and secondly because
these volume in which they were built would not cover the cost of the
testing.
If one took the films used twenty years ago for, say, an S-100 board set and
made it available as a kit, i.e. with all the IC's, passives, and hardware,
it would cost quite a bit more than it did back 20 years ago. That's
because of inflation and because labor to buy, stock , kit, and document the
thing would cost more, not just the difference for inflation, but really
more, because the labor cost buys less these days, and because people simply
expect more than they once did. It would also make sense to silkscreen as
much of the documentation for jumper and switch settings onto the board so
the user can't lose it. Though the old IMSAI boards I have are
solder-masked, the old ALTAIR ones are not. That could complicate building
a kit as well, particularly for folks not experienced with soldering.
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.
Frequently one finds places where key words and phrases have been left out .
. . words like "not" . . .
Dick
-----Original Message-----
From: Philip.Belben(a)pgen.com <Philip.Belben(a)pgen.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, March 31, 1999 10:04 AM
Subject: Re: Kits vs ready-made (was RE: Rebirth of IMSAI)
>
>Sorry if this thread is old hat now - I've been having a hard time keeping
up
>with the volume of traffic here recently.
>
>> Kits are often more costly than ready-built products because kit builders
>> fix their mistakes, while you can't expect the user of ready-made stuff
to
>> fix your mistakes. Tech support is a necessity, yet most kit builders
don't
>> need it. Tech support is what costs when you're selling a ready-built
>> product for the home computer market.
>
>
>This is strange. You are saying: Tech support is what costs. Kits don't
need
>so much. Therefore kits are more expensive. ???
>
>I claim the other way around. Most kit suppliers have to spend _more_ on
>technical support because they have to help people who try kits too hard
for
>them and expect the supplier to sort out their mistakes.
>
>Kits generally have shorter production runs than complete units, hence less
>quantity discount / economy of scale.
>
>Finally, kits are generally better documented than complete units sold as
such.
>And documentation costs a lot!
>
>Philip.
>
>
>
>
>
