>I have read something at applefritter that intrigued me: that Apple was
>thinking about marketing a system known as the "Johnathon" (Successor the
>the Mac, perhaps?). The basic design was very similar to that of an Acorn
>RISC PC: You bought the base "module" (What OS that run? Mac OS?) as it was
>called, & you could buy additional modules that would allow you to run other
>operating systems. Unfortunately, Apple canned this computer because they
>thought that everybody would just buy the MS-DOS module.
>
>My question is: Was this the original concept for the Mac II, or is this
>something completely diffrent.
No. Johnathan and the Mac II were in fact competing projects.
The book AppleDesign has some beautiful pictures of the system as well as a nice overview:
http://www.amazon.com/exec/obidos/ASIN/1888001259/theapplefritter
Tom
------------------------------Applefritter------------------------------
Apple Prototypes, Clones, & Hacks - The obscure, unusual, & exceptional.
---------------------<http://www.applefritter.com/>---------------------
>I have in my posession one of the few real Mac Clones....It's called
>the Jonathan by Akkord Computer out of Taiwan. It's a real clone with
>the exception of the Mac ROMs, the hardware was all original and supposed
>to get around a lot of the Apple patents. It's a neat little machine, I
>met the Akkord guys back in 1990-91.
I'm reading the archives, so I can't see your email address, but would you like to provide some
pictures for Applefritter?
A response off list is fine.
Thanks,
Tom Owad
------------------------------Applefritter------------------------------
Apple Prototypes, Clones, & Hacks - The obscure, unusual, & exceptional.
---------------------<http://www.applefritter.com/>---------------------
[Please email me if you feel this announcement is not appropriate for the
classiccmp mailing list.]
You can now get xtrs version 4.3, a Radio Shack TRS-80 Model I/III/4/4P
emulator for Unix and the X Window System, from my TRS-80 Web pages:
http://www.tim-mann.org/xtrs.html
Version 4.3 adds emulation of the serial port (connecting to a Unix tty
device), and of both Radio Shack and Micro Labs hi-res graphics cards
for the Model III. There are also several small bug fixes. See the included
ChangeLog for details.
Thanks to the folks who sent me information on Model III graphics cards
in response to my request in the xtrs 4.2 announcement! Now I have another
request: can anyone send me specs for TRS-80 joysticks?
General xtrs blurb:
xtrs is a Radio Shack TRS-80 Model I/III/4/4P emulator for Unix and the
X Window System. It includes lower case, the real time clock, hi-res
graphics, serial port, parallel printer, mouse, cassette, sound and music
output (requires OSS), 5" and 8" floppy disk drives in single and double
density, and even hard disk drives. The emulated floppy and hard disk
file formats are compatible with the popular MSDOS-based emulators by
Jeff Vavasour, Matthew Reed, and David Keil, and (if you choose a capable
enough file format), all features of the original TRS-80 floppy disk
controller are emulated. Under Linux, physical floppy disk drives are
also supported. Physical cassettes can be read and written too. The user
interface is a bit spartan, but it gets the job done.
Tim Mann tim.mann(a)compaq.com http://www.tim-mann.org
Compaq Computer Corporation, Systems Research Center, Palo Alto, CA
Hello all,
I'm back after a month and a half long hiatus. Is there an up-to-date archive of the list publicly
available so that I can catch up on my reading? All of the ones I've managed to find are outdated.
Thanks.
Tom
------------------------------Applefritter------------------------------
Apple Prototypes, Clones, & Hacks - The obscure, unusual, & exceptional.
---------------------<http://www.applefritter.com/>---------------------
> -----Original Message-----
> From: ard(a)p850ug1.demon.co.uk [mailto:ard@p850ug1.demon.co.uk]
> Sent: Friday, July 21, 2000 6:05 PM
> To: classiccmp(a)classiccmp.org
> Subject: Re: Other useful test equipment (was: RE: Scope use...)
>
>
> > One last word on test equipment. Unless you are into vintage
> > test equipment collecting (a very respectable hobby in it's own
> > right!) I suggest that you try to get the most modern/reliable
> > version you can _reasonably_ afford, especially if your point
>
> Relaible, sure, but not necessarily modern.
>
> Often the choice (at least for a hobbyist) is between an
> older high-class instrument (like a Tektronix 'scope) and a more modern,
> cheaper, and much worse instrument.
I agree with this in concept. What you're shooting for above
all is _quality_ of design. My point was that given 2 O'scopes,
One by HP and One by Tektronix (both quality manufacturers)
approx. same condition and at approximately the same price,
I would lean towards the one with the newest fabrication date.
This is especially true if you are considering 2 scopes of the
same model/manufacturer. The newer model will most likely have
the newest engineering revisions/mods.
>
> Take the better one _every time_. You may have to spend a
> couple of days repairing it, but after that it will be reliable
> again. And it will work properly.
Here again, I agree with this in principle. My only comment is that
you should _know_ what you are doing if you buy a 'Scope with
problems. If you feel comfortable with your ability to repair
this level of equipment, you can end up with some real bargains!
But then again, I didn't target the original post to those people,
as they already know what they are doing. If you look at the root
message that this thread was derived from, it concerned someone
asking on how to "use" a scope to debug digital hardware.
We must keep in mind that a lot of people on the mailing list are
"digital" experts (except for all you PDP-8 owners with "real"
Transistor logic flipchips :-), and most older scopes are as far from
"digital" internally as you can get. Different worlds.
> You will be able to trust the results you get from it. Some
> hobbyist-grade instruments couldn't possible give sensible results !
> A lot of cheap 'scopes don't trigger properly -- I have seen one that
> can't trigger on a 1kHz TTL square wave (!). And without a
> decent trigger
> system you won't get a stable trace, and without a stable
> trace you can't
> make measurements.
>
> My first 'scope was a Solartron CD1400. Old, valved, and not
> particularly
> high spec (15MHz IIRC). I spent a good few days tracking down
> the open
> resistor on the timebase PCB. After I'd done that I had a 'scope that
> worked and which still works some 20 years later (it's needed _no_
> repairs in those 20 years). Having seen some of the modern
> 'cheap scopes'
> (that would have cost about 20 times what I paid for the
> Solartron), I
> know I made the right decision.
>
>
> > in obtaining it is to use it to debug something else. This goes
> > for O'scopes as well as Logic Analyzers, meters, etc.
> > As any engineer will tell you, you want to reduce the number of
> > variables in a problem you are trying to troubleshoot, and the
> > last thing you need in such a situation is a piece of test
> > equipment that you can't trust. Also be realistic in your
>
> True. But don't make the mistake of thinking that a new instrument is
> _necessarily_ a trustworthy instrument. And don't make the mistake of
> assuming that if you get 'crazy results' that the instrument
> is working fine, no matter how good a brand it is, and how new it is.
> _Check it_.
>
I couldn't agree with you more! The primary ingredient of troubleshooting
is Common Sense. If your test equipment is telling you nonsense, then
suspect the test gear. Of course, experience is the greatest way to
develop Common Sense.
> It doesn't take long to ensure that the 'scope gives a sensible
> trace when tapped on the supply line. Or when connected to a known-good
clock
> generator. And it might save many hours of looking for a
> non-existant fault!
>
> It is well worth learning how to verify that your instruments
> are giving sensible results. Not necessarily knowing how to calibrate
> them (because 99% of the time you don't need accuracy). But at least
> to ensure that they're not out by a factor of 10. Or that the 'scope
> hasn't suddenly lost all high frequency response, or that it's ringing
> like crazy on a sharp edge.
>
> > selection. If you have a choice between an 1997 Fluke DVM (in
> > good condition) and a 2000 "Bonusmart blisterpack special"
> > you might be much better off choosing the Fluke from a
> > reliability/dependability viewpoint.
>
> Err, 1997 is not old. Any Fluke meter that didn't last at
> least 10 years would disappoint me...
Agreed... I just picked that date at random. I still use an
analog meter (Brain Rot has caused me to block out the Manufacturer
at the momement... perhaps a Triplett Mod 260? Black thing with a
mirrored scale...oh well :-)when working on some circuits. It's
older than sin, but as far as I'm concerned, it's one of the
best analog meters around.
>
> Given the choice between a 1960's Fluke/Solartron/HP and a modern
> no-name, I'd probably take the older instrument. Spend a few
> days getting it back to rights. And then know it would carry on working.
>
> -tony
>
I picked up a Tek 2230, a 100 MHz two-channel digital storage oscilloscope
for $150 today, on a rolling stand. It shows signs of life in the sense
that the display works and the buttons seem to have some effect, like
stepping through menus.
I've always wanted a nice 'scope, even though I have very little experience
using one. Where do I begin? I have no manual, just the little tech ref
booklet. A manual sold on eBay a few weeks ago for $25 or so. It has a
half-dozen probes.
Was this a good deal? I found a number of refurb places on the web selling
them for $1400-$2500.
- John
The 2230 Digital Storage Oscilloscope is a combination
non-storage and digital storage dual-channel 100 MHz
bandwidth instrument. It is a rugged, lightweight
oscilloscope featuring microprocessor operation and
alphanumeric CRT readout of many of the front panel
controls. In the digital storage mode, up to three
waveform sets (CH 1 and/or CH 2) may be stored in a
save ref. memory and recalled for display at a later
time. The digital storage sampling rate is 20
megasamples per second maximum, and the acquired
record length is 4 k samples (1 k may also be selected)
for a single channel or 2 k samples for dual-channel
(Chop or Alt) displays. Manufacturer's Standard
Accessories 2 10X Voltage Probes Front Panel Cover
Accessory Pouch Operators Manual Users Reference
Card Manufacturer's Options Option 10 = GPIB IEEE-488
Interface includes 26K battery backed memory
Tektronix 2230
This is a 100MHz, digital storage and non-storage oscilloscope. Features
include cursors for time and voltage measurements, 100ns glitch capture,
and signal averaging.
TEKTRONIX/ 2230 100 MHz Digitizing Oscilloscope
100 MHz, 2 channel, combination analog and digital storage oscilloscope.
Features microprocessor operation and alphanumeric CRT readout of many
of the front panel controls. Up to three waveform sets may be stored
in digital storage mode.
Dual Mode portable Oscilloscope. Bandwidth: DC to 100 MHz (storage or non-storage),
Single-shot: 2 MHz (single channel). Vertical deflection factors: 2 mV/div to
5 V/div. Sweep Ranges: 0.05us to 0.5 s/div. Triggering modes: Normal, P-P,
Auto, TV Line, TV Field, Single Sweep, and HF Reject. Glitch capture: 100ns.
Record Length: 4K. Sampling Speed: 20 MSa/s with 10 bit vertical resolution.
Switch between real time analog ? digital storage modes at a touch of a button.
Full waveform measurements with on screen cursors. 4 memory locations.
Hi, I'm new to the list,
was wondering if anyone could help me with a Compucorp 140
(Statistician) nixie tube calculator I found the other day.
The calc is missing a couple of items. I was wondering if anyone has a
power cord (fits 1 in dia socket with 3 pins in equilateral triangle on
3/8" spacing), 'chg sign' key, 'reset' key and the key with 2 bell
shaped curves on it (or a complete junk unit).
I would be greatful for any help
Mitch Billian
OK, to clarify, what I'm asking about is whether or not all 11/34A PSU's
have those three particular power supplies in the main box and if so, is
that where those three belong?
Will J
________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
> -----Original Message-----
> From: Douglas Quebbeman [mailto:dhquebbeman@theestopinalgroup.com]
> Sent: Friday, July 21, 2000 3:17 PM
> To: 'classiccmp(a)classiccmp.org'
> Subject: RE: Other useful test equipment (was: RE: Scope use...)
>
>
> > I'll second that. I picked up a used HP 16xx something or
> other with 4
> > pods of 8 inputs each, and it's been so useful debugging my home
> > designs. An alternative would be a PC parallel port
> based model, but
> > they seem kind of cheesy compared to a nice, solid, HP unit.
>
> I used an (older?) HP Logic Analyzer that appeared to be an embedded
> Macintosh; I never opened it up to make that determination, though,
> as it was on lease.
I don't know about the earlier HP units, but I think a number of
the really _early_ designs for logic analyzers were based on some
of the microprocessing systems available at the time. At one
time I had 2 logic analyzers, both made by Nicolet, separated by
a few years. The innards of the earlier (and smaller) unit turned
out to be a repackaged Apple II. the later unit was a Z80 based
CP/M unit with a built-in 5.25" drive. It even came with a
CP/M boot disk that turned the unit into a general CP/M machine.
>
> Are these the vintage of units that are being dumped?
>
> -dq
>
No, I didn't mean to imply that any particular manufacturer's units
were being dumped on the market... although I have noticed quite
a number of HP1631A and D systems at the hamfests in my area
of the country (VA-MD). My current analyzer is a HP1631D, and I
paid < $200 (with probes.) It has a 200 Mhz sample rate (50 Mhz
analog bandwidth.) It can even display analog waveforms, so you
can use it as an Digital O'scope in some situations.
We still use this same model where I work, and I am
very pleased with it.
BTW, A number of pieces of HP equipment of this era (circa 1985)
shared the same physical "look", i.e. the HP1631D Logic analizer
looks virtually identical the the HP54201D (and HP54101?)
Digital O'scopes (unless you pay close attention to the
button legends and nameplate), so If you happen across a
stack of identical HP equipment at a hamfest, don't assume
that they are all the same model from simply a casual glance.
One last word on test equipment. Unless you are into vintage
test equipment collecting (a very respectable hobby in it's own
right!) I suggest that you try to get the most modern/reliable
version you can _reasonably_ afford, especially if your point
in obtaining it is to use it to debug something else. This goes
for O'scopes as well as Logic Analyzers, meters, etc.
As any engineer will tell you, you want to reduce the number of
variables in a problem you are trying to troubleshoot, and the
last thing you need in such a situation is a piece of test
equipment that you can't trust. Also be realistic in your
selection. If you have a choice between an 1997 Fluke DVM (in
good condition) and a 2000 "Bonusmart blisterpack special"
you might be much better off choosing the Fluke from a
reliability/dependability viewpoint.
-al-
-acorda(a)1bigred.com
