27 Feb
2024
27 Feb
'24
2:58 p.m.
Hi Jon!
think the Bendix G-15 had cassettes for the 5-level
tape
they used.
Aha, interesting! Did a short search, but have not been able to
find a picture of a casette. Just a pile of paper tape instead ;-)
https://images.app.goo.gl/HYqkpYHJUxZeGfiA8
of mylar tape instead of paper. OS boot tapes might
be punched
on that.
Yes, for heavy use (and e.g. humid environments), the mil guys obviously
used Mylar or heavily oiled tape. Although not experrienced myself, I was
told that the Mylar tape cuts through the guiding pins of the readers over
time. And yes, it also may easily cut one's fingers ;-)
much like plain paper tape, and simple mylar alone.
The latter often
comes metallized on one side, and is glossy.
Yes, that is the one within the casette and the aluminum as you expect
is for optical reading (Most plastics including Mylar are quite
transparent for IR light and in the old days, when thungsten bulbs
where used, the IR part of the light was the major part contributing
to the response of the photodiodes!
input medium for the university mainframe computer
(Electrologica X8),
they used optical readers rated at 2000 characters per second.
Wow - that is indeed pretty fast!!! My FACIT is 1200cps maximum and
stopping "on character" as it is called is VERY hard at that speed.
But buffering helps here and in case of the 920M, the casette is
used for, there was no buffering. So software needs to be read in
one run.
Best wishes,
Erik.
''~``
( o o )
+--------------------------.oooO--(_)--Oooo.-------------------------+
| Dr. Erik Baigar Inertial Navigation & |
| Salzstrasse 1 .oooO Vintage Computer |
| D87616 Marktoberdorf ( ) Oooo. Hobbyist / Physicist |
| erik(a)baigar.de +------\ (----( )---------------------------+
| www.baigar.de | \_) ) /
+----------------------+ (_/
27 Feb
27 Feb
4:20 p.m.
New subject: Paper tape in casettes...
It's not a cassette, but the PB-440 (Pitney-Bowes), renamed Raytheon 440 and its
upgrade the raytheon 520 had a large reel paper tape with a bidirectional read and an
"operating system" Load the os, say we want to run fortran, spin down to
fortran, read the program in on 80 column cards (probably 2 pass, I don'trecall),
automatically reload the monitor when done, read and execute the program from cards.
Frequently used programs could be on the OS paper tape reel.
btw, that computer was user level microcode. multiple "machine" definitions,
with typical 24 bit word, one instruction set optimized for fortran execution, one for
fortran compilation, etc (don't remember exactly, as I only programmed in the
microcode of mostly 2 micro instructions per word).
<pre>--Carey</pre>
On 02/27/2024 8:58 AM CST erik--- via cctalk
<cctalk(a)classiccmp.org> wrote:
Hi Jon!
think the Bendix G-15 had cassettes for the
5-level tape
they used.
6:10 p.m.
New subject: Paper tape in casettes...
On 2024-02-27 9:20 a.m., CAREY SCHUG via cctalk wrote:
It's not a cassette, but the PB-440
(Pitney-Bowes), renamed Raytheon 440 and its upgrade the raytheon 520 had a large reel
paper tape with a bidirectional read and an "operating system" Load the os, say
we want to run fortran, spin down to fortran, read the program in on 80 column cards
(probably 2 pass, I don'trecall), automatically reload the monitor when done, read and
execute the program from cards. Frequently used programs could be on the OS paper tape
reel.
btw, that computer was user level microcode. multiple "machine" definitions,
with typical 24 bit word, one instruction set optimized for fortran execution, one for
fortran compilation, etc (don't remember exactly, as I only programmed in the
microcode of mostly 2 micro instructions per word).
<pre>--Carey</pre>
Where is some document ion on that machine?
I finally got around to building the TTL home-brew computer I wanted
from the 1970's and now I need all the goodies like paper tape and i/o
that is Algol ready. :)
Ben.
OK I cheated using Cmos 2901's and 22v10's, but that is what I had
to make the PCB layouts easy.I don't think 1 74H04 counts for making it
a TTL computer. :)
PS: With low cost Chinese PCB's and vintage parts, why are people not
building real hardware replica's of interesting machines.
6:40 p.m.
New subject: Paper tape in casettes...
On 2/27/24 10:10, ben via cctalk wrote:
On 2024-02-27 9:20 a.m., CAREY SCHUG via cctalk
wrote:
> It's not a cassette, but the PB-440 (Pitney-Bowes), renamed Raytheon
> 440 and its upgrade the raytheon 520 had a large reel paper tape with
> a bidirectional read and an "operating system" Load the os, say we
> want to run fortran, spin down to fortran, read the program in on 80
> column cards (probably 2 pass, I don'trecall), automatically reload
> the monitor when done, read and execute the program from cards.
> Frequently used programs could be on the OS paper tape reel.
>
> btw, that computer was user level microcode. multiple "machine"
> definitions, with typical 24 bit word, one instruction set optimized
> for fortran execution, one for fortran compilation, etc (don't
> remember exactly, as I only programmed in the microcode of mostly 2
> micro instructions per word).
Is the "PB" Pitney-Bowes or Packard-Bell? I note that only because that
Raytheon bought out Packard-Bell's computer operation and re-dubbed
their models. So a Packard-Bell PB 250 became the Raytheon PB 250.
As regards the 440, it's on my short list of interesting "hybrid"
computers of the 1960s, which was a hot topic then: It was part of the
TRICE setup:
http://www.bitsavers.org/pdf/raytheon/trice/TRICE_440_Oct64.pdf
--Chuck
9:28 p.m.
New subject: PB-440 [was: Paper tape in casettes...]
you are correct. Packard Bell. apologies. And the picture on page 8 is (or is close to)
the paper tape reader I remember. So many fun things to program (I programmed in octal
only).
conditional instructions were "skip if", so if the first microinstruction in the
word, applied to the
second, if the second, applied to the next word, that is, 2 micro instructions, the first
of which
might also be a conditional...
two relative jumps in one word allowed a jump to be twice as big.
I *think* I should have the microcode programming book for this on paper. all boxed up
when I got
married and never unboxed after the divorce. brown and black cover.
<pre>--Carey</pre>
On 02/27/2024 12:40 PM CST Chuck Guzis via cctalk
<cctalk(a)classiccmp.org> wrote:
On 2/27/24 10:10, ben via cctalk wrote:
Is the "PB" Pitney-Bowes or Packard-Bell? I note that only because that
Raytheon bought out Packard-Bell's computer operation and re-dubbed
their models. So a Packard-Bell PB 250 became the Raytheon PB 250.
As regards the 440, it's on my short list of interesting "hybrid"
computers of the 1960s, which was a hot topic then: It was part of the
TRICE setup:
http://www.bitsavers.org/pdf/raytheon/trice/TRICE_440_Oct64.pdf
--Chuck
> On 2024-02-27 9:20 a.m., CAREY SCHUG via cctalk
wrote:
>> It's not a cassette, but the PB-440 (Pitney-Bowes), renamed Raytheon
>> 440 and its upgrade the raytheon 520 had a large reel paper tape with
>> a bidirectional read and an "operating system" Load the os, say we
>> want to run fortran, spin down to fortran, read the program in on 80
>> column cards (probably 2 pass, I don'trecall), automatically reload
>> the monitor when done, read and execute the program from cards.
>> Frequently used programs could be on the OS paper tape reel.
>>
>> btw, that computer was user level microcode. multiple "machine"
>> definitions, with typical 24 bit word, one instruction set optimized
>> for fortran execution, one for fortran compilation, etc (don't
>> remember exactly, as I only programmed in the microcode of mostly 2
>> micro instructions per word).
9:45 p.m.
New subject: PB-440 [was: Paper tape in casettes...]
On 2/27/24 13:28, CAREY SCHUG wrote:
you are correct. Packard Bell. apologies. And the
picture on page 8 is (or is close to)
the paper tape reader I remember. So many fun things to program (I programmed in octal
only).
I like the description on that same page referring to "octal arabic
character" as opposed to, say, Babylonian character. :)
--Chuck
8:13 p.m.
New subject: Paper tape in casettes...
On Tue, Feb 27, 2024 at 11:10:34AM -0700, ben via cctalk wrote:
PS: With low cost Chinese PCB's and vintage parts,
why are people not
building real hardware replica's of interesting machines.
But they are..
I can't tell what you'd find interesting since the list is pretty wide.
I've got an Apple I replica board that someday I intend to populate and get running.
You've got the ReAmiga project producing new boards for using up old parts on broken
boards.
https://www.reamiga.info/?page_id=36
One thing that I find interesting (although I'd never do it), is a board to emulate
a 68000 CPU at much higher speeds running barebones emulator on a Raspberry Pi.
Aimed at Amiga A1200 again.
https://wiki.amiga.org/index.php?title=Pistorm32-Lite
I've put together my IMSAI 8080 frontpanel kit, with the CPU emulated on an ESP32.
https://thehighnibble.com/imsai8080/
Or they are about to ship out the PiDP-10 blinkenlights kits
https://obsolescence.dev/pidp10.html
The CPU again emulated on a RaPi, but all new boards and plastic for the console kit
I'm not sure if anybody has ever thought about making flipchip boards themselves
though.
Although they might have been..
https://forum.vcfed.org/index.php?threads/a-general-purpose-flip-chip-adapt…
9:30 p.m.
New subject: Paper tape in casettes...
On 2024-02-27 1:13 p.m., Doug McIntyre via cctalk wrote:
On Tue, Feb 27, 2024 at 11:10:34AM -0700, ben via
cctalk wrote:
Anything not APPLE or IBM or DEC or a PI-emulation for a home brew
computer.
PS: With low cost Chinese PCB's and vintage
parts, why are people not
building real hardware replica's of interesting machines.
But they are..
I can't tell what you'd find interesting since the list is pretty wide.
I've got an Apple I replica board that someday I
intend to populate and get running.
1) Get a good power supply
2) hack in a 6809.
3) get a good power supply.
You've got the ReAmiga project producing new
boards for using up old parts on broken boards.
https://www.reamiga.info/?page_id=36
One thing that I find interesting (although I'd never do it), is a board to emulate
a 68000 CPU at much higher speeds running barebones emulator on a Raspberry Pi.
Aimed at Amiga A1200 again.
https://wiki.amiga.org/index.php?title=Pistorm32-Lite
I've put together my IMSAI 8080 frontpanel kit, with the CPU emulated on an ESP32.
https://thehighnibble.com/imsai8080/
I had z80/s100 kit once, but the power supply failed taking every thing out.
Or they are about to ship out the PiDP-10
blinkenlights kits
https://obsolescence.dev/pidp10.html
The CPU again emulated on a RaPi, but all new boards and plastic for the console kit
I think the PI is too cheap of computer build wise for emulation
of any system. It might blink your lights, but never run 20 users
timesharing.
I'm not sure if anybody has ever thought about
making flipchip boards
themselves though.
Although they might have been..
https://forum.vcfed.org/index.php?threads/a-general-purpose-flip-chip-adapt…
Small PCB's run at $5 each and PAL 22v10 in each could replace a lot
simple cards.
I would love to see a PDP-8 with 1/2 size flip chips using today's
smaller logic.
A good home brew computer is what I am looking for.
In hindsight I want 18 bit addressing (bytes optional)
and single word memory ref's. Since 2901 alu's are 4
bits wide, 20,24,28 bits are my only option for a COMPUTER
not for digital controller faking it.
Still working on the pro-type stage here.
For test pcb's I have,
good source of Chinese toggle switches with a PCB foot print.
https://www.ebay.ca/itm/143887059040
Hex displays are here.
https://www.ebay.ca/itm/281809099152
10:31 p.m.
New subject: Paper tape in casettes...
> I would love to see a PDP-8 with 1/2 size flip
chips using today's smaller logic.
Can you get the logic ? Especially the bus / backplane driving parts.
https://retrocmp.com/projects/qbone/326-qbone-unibone-alternative-bus-drive…
Q-bus transceivers (DS8641 being a classic) are unobtainium in commercial qtys, the
substitutes listed seem little more available
Omnibus parts ...
https://www.microchip.com/en-us/product/pic16f13145
An 8..28 pin microcontroller with 32 (4-1) LUTs on 1.8 - 5 V supply, might control output
transistors for roll your own bus transceivers
Small, cheap and perhaps sufficiently fast / flexible; also, perhaps competition for the
22V10 ?
Martin
10:42 p.m.
New subject: Paper tape in casettes...
Take a look at the Applesauce.
It hooks up to a lot of different floppy drives and records and decodes the flux.
Version2 of the hardware is being sourced and should be available in a few months.
Sent from my iPhone
On Feb 27, 2024, at 14:32, Martin Bishop via cctalk
<cctalk(a)classiccmp.org> wrote:
> I would love to see a PDP-8 with 1/2 size flip chips using today's smaller
logic.
Can you get the logic ? Especially the bus / backplane driving parts.
https://retrocmp.com/projects/qbone/326-qbone-unibone-alternative-bus-drive…
Q-bus transceivers (DS8641 being a classic) are unobtainium in commercial qtys, the
substitutes listed seem little more available
Omnibus parts ...
https://www.microchip.com/en-us/product/pic16f13145
An 8..28 pin microcontroller with 32 (4-1) LUTs on 1.8 - 5 V supply, might control output
transistors for roll your own bus transceivers
Small, cheap and perhaps sufficiently fast / flexible; also, perhaps competition for the
22V10 ?
Martin
10:50 p.m.
New subject: applesauce vs western digital emulator
but still only floppy speeds. maybe they have software mods for larger capacity, but
still only floppy speeds. emulate the western digital chip and go as fast as the
original machine can handle it.
there were non-apple disk emulators (including one designed for automatic loom weavers or
something).
I think still would be far more expensive than circuitry to decode floppy drive data
lines.
<pre>--Carey</pre>
On 02/27/2024 4:42 PM CST Wayne S via cctalk
<cctalk(a)classiccmp.org> wrote:
Take a look at the Applesauce.
It hooks up to a lot of different floppy drives and records and decodes the flux.
Version2 of the hardware is being sourced and should be available in a few months.
11:26 p.m.
New subject: applesauce vs western digital emulator
On 2/27/24 14:50, CAREY SCHUG via cctalk wrote:
but still only floppy speeds. maybe they have
software mods for larger capacity, but
still only floppy speeds. emulate the western digital chip and go as fast as the
original machine can handle it.
There are inexpensive floppy emulators available with custom software.
Search for "Gotek". You can even modify the basic cheap unit to have a
small OLED screen and a rotary encoder for switching among the hundreds
of images that you've recorded using your Greaseweazle.
The Gotek is essentially a cheap MCU-with some level-shifting logic and
a USB port for a pen drive.
There is also an emulator for an MFM hard drive. Silicon just keeps
marching on...
--Chuck
11:02 p.m.
New subject: Paper tape in casettes...
On 2/27/24 14:42, Wayne S via cctalk wrote:
Take a look at the Applesauce.
It hooks up to a lot of different floppy drives and records and decodes the flux.
Version2 of the hardware is being sourced and should be available in a few months.
Good grief, there are more of these things floating around than one can
shake a stick at. The Greasweazel is perhaps the cheapest, using a $3
($1.30 or so from Aliexpress) STM32F103 "Blue Pill" board.
It's almost trivial doing this if you don't need the "eye candy".
Basically you run a timer in capture mode, with capture triggered by an
edge on the drive's "read data" line.
Modern MCUs don't even break a sweat doing this.
It's nice seeing the proliferation after many years of harping on the
subject...
--Chuck
11:12 p.m.
New subject: Paper tape in casettes...
Chuck, not to disagree much, because you are an expert, but there’s more to decoding
floppies than just reading them. Some floppies have tracks that are recorded at different
speeds. Some have tracks that use different modulation gcr on some and mfm on others. A
lot of floppies have different skew. The applesauce tries to handle these problems and
give you a readable file. It’s mostly in the software.
I tried to send the discord link but don’t know if it got thru so here it is again
https://discord.gg/njetE8zU
Wayne
Sent from my iPhone
On Feb 27, 2024, at 15:02, Chuck Guzis via cctalk <cctalk(a)classiccmp.org> wrote:
On 2/27/24 14:42, Wayne S via cctalk wrote:
Take a look at the Applesauce.
It hooks up to a lot of different floppy drives and records and decodes the flux.
Version2 of the hardware is being sourced and should be available in a few months.
Good grief, there are more of these things floating around than one can
shake a stick at. The Greasweazel is perhaps the cheapest, using a $3
($1.30 or so from Aliexpress) STM32F103 "Blue Pill" board.
It's almost trivial doing this if you don't need the "eye candy".
Basically you run a timer in capture mode, with capture triggered by an
edge on the drive's "read data" line.
Modern MCUs don't even break a sweat doing this.
It's nice seeing the proliferation after many years of harping on the
subject...
--Chuck
11:18 p.m.
New subject: Paper tape in casettes...
The “support” channel has the most info on the applesause.
Sent from my iPhone
On Feb 27, 2024, at 15:12, Wayne S <wayne.sudol(a)hotmail.com> wrote:
Chuck, not to disagree much, because you are an expert, but there’s more to decoding
floppies than just reading them. Some floppies have tracks that are recorded at different
speeds. Some have tracks that use different modulation gcr on some and mfm on others. A
lot of floppies have different skew. The applesauce tries to handle these problems and
give you a readable file. It’s mostly in the software.
I tried to send the discord link but don’t know if it got thru so here it is again
https://discord.gg/njetE8zU
Wayne
Sent from my iPhone
On Feb 27, 2024, at 15:02, Chuck Guzis via cctalk <cctalk(a)classiccmp.org> wrote:
On 2/27/24 14:42, Wayne S via cctalk wrote:
Take a look at the Applesauce.
It hooks up to a lot of different floppy drives and records and decodes the flux.
Version2 of the hardware is being sourced and should be available in a few months.
Good grief, there are more of these things floating around than one can
shake a stick at. The Greasweazel is perhaps the cheapest, using a $3
($1.30 or so from Aliexpress) STM32F103 "Blue Pill" board.
It's almost trivial doing this if you don't need the "eye candy".
Basically you run a timer in capture mode, with capture triggered by an
edge on the drive's "read data" line.
Modern MCUs don't even break a sweat doing this.
It's nice seeing the proliferation after many years of harping on the
subject...
--Chuck
11:33 p.m.
New subject: emulating floppies [was: Paper tape in casettes...]
I knew most of this, which is why emulating the floppy controller should be easier.
applesauce is platform specific (ok, ANY floppy emulation will be platform specific for
apple)
I thought the applesauce page said it was not yet available for standard shugart style as
in trs-80, s-100...
greaseweasel is platform specific. the color coco is not yet available in the USA,
needing shipping from Europe, which in my experience is not cheap. not even promised for
trs80 1/3/4 or s-100. and are the parts cheap? dunno.
did not know about gcr/mfm on same floppy...if you respond, please mention who does that.
gaak, I don't even
recognize "gcr" at this point. I remember mfm and something else. mfm was
single density, right? was gcr
double density? does not seem familiar, but certainly there was a double density encoding
scheme that the
device attached to the floppy cable would have to recognize.
I had forgotten that atari? commodore? changed speed, though I remember I knew that
before.
<pre>--Carey</pre>
On 02/27/2024 5:18 PM CST Wayne S via cctalk
<cctalk(a)classiccmp.org> wrote:
The “support” channel has the most info on the applesause.
Sent from my iPhone
On Feb 27, 2024, at 15:12, Wayne S <wayne.sudol(a)hotmail.com> wrote:
Chuck, not to disagree much, because you are an expert, but there’s more to decoding
floppies than just reading them. Some floppies have tracks that are recorded at different
speeds. Some have tracks that use different modulation gcr on some and mfm on others. A
lot of floppies have different skew. The applesauce tries to handle these problems and
give you a readable file. It’s mostly in the software.
I tried to send the discord link but don’t know if it got thru so here it is again
https://discord.gg/njetE8zU
Wayne
Sent from my iPhone
On Feb 27, 2024, at 15:02, Chuck Guzis via cctalk <cctalk(a)classiccmp.org> wrote:
On 2/27/24 14:42, Wayne S via cctalk wrote:
Take a look at the Applesauce.
It hooks up to a lot of different floppy drives and records and decodes the flux.
Version2 of the hardware is being sourced and should be available in a few months.
Good grief, there are more of these things floating around than one can
shake a stick at. The Greasweazel is perhaps the cheapest, using a $3
($1.30 or so from Aliexpress) STM32F103 "Blue Pill" board.
It's almost trivial doing this if you don't need the "eye candy".
Basically you run a timer in capture mode, with capture triggered by an
edge on the drive's "read data" line.
Modern MCUs don't even break a sweat doing this.
It's nice seeing the proliferation after many years of harping on the
subject...
--Chuck
11:43 p.m.
New subject: emulating floppies [was: Paper tape in casettes...]
I know you do this for a living and are good at it. Most of us don’t do it as a living but
have piles of floppies that we want to recover cheaply using an existing method. Grease,
cat and other wezels, are fine but you have to do more work to get usable stuff, unless
your floppies are all c64 😀 The applesauce just seems further along than the others.
Just my opinion.
Sent from my iPhone
On Feb 27, 2024, at 15:33, CAREY SCHUG via cctalk
<cctalk(a)classiccmp.org> wrote:
I knew most of this, which is why emulating the floppy controller should be easier.
applesauce is platform specific (ok, ANY floppy emulation will be platform specific for
apple)
I thought the applesauce page said it was not yet available for standard shugart style as
in trs-80, s-100...
greaseweasel is platform specific. the color coco is not yet available in the USA,
needing shipping from Europe, which in my experience is not cheap. not even promised for
trs80 1/3/4 or s-100. and are the parts cheap? dunno.
did not know about gcr/mfm on same floppy...if you respond, please mention who does that.
gaak, I don't even
recognize "gcr" at this point. I remember mfm and something else. mfm was
single density, right? was gcr
double density? does not seem familiar, but certainly there was a double density
encoding scheme that the
device attached to the floppy cable would have to recognize.
I had forgotten that atari? commodore? changed speed, though I remember I knew that
before.
<pre>--Carey</pre>
> On 02/27/2024 5:18 PM CST Wayne S via cctalk <cctalk(a)classiccmp.org> wrote:
>
>
> The “support” channel has the most info on the applesause.
>
>
> Sent from my iPhone
>
> On Feb 27, 2024, at 15:12, Wayne S <wayne.sudol(a)hotmail.com> wrote:
>
> Chuck, not to disagree much, because you are an expert, but there’s more to
decoding floppies than just reading them. Some floppies have tracks that are recorded at
different speeds. Some have tracks that use different modulation gcr on some and mfm on
others. A lot of floppies have different skew. The applesauce tries to handle these
problems and give you a readable file. It’s mostly in the software.
>
> I tried to send the discord link but don’t know if it got thru so here it is again
>
> https://discord.gg/njetE8zU
>
> Wayne
>
>
> Sent from my iPhone
>
> On Feb 27, 2024, at 15:02, Chuck Guzis via cctalk <cctalk(a)classiccmp.org>
wrote:
>
> On 2/27/24 14:42, Wayne S via cctalk wrote:
> Take a look at the Applesauce.
> It hooks up to a lot of different floppy drives and records and decodes the flux.
> Version2 of the hardware is being sourced and should be available in a few months.
>
> Good grief, there are more of these things floating around than one can
> shake a stick at. The Greasweazel is perhaps the cheapest, using a $3
> ($1.30 or so from Aliexpress) STM32F103 "Blue Pill" board.
>
> It's almost trivial doing this if you don't need the "eye candy".
> Basically you run a timer in capture mode, with capture triggered by an
> edge on the drive's "read data" line.
>
> Modern MCUs don't even break a sweat doing this.
>
> It's nice seeing the proliferation after many years of harping on the
> subject...
>
> --Chuck
11:48 p.m.
New subject: emulating floppies [was: Paper tape in casettes...]
Vector uses gcr. Apparently.
I’m not well versed in any of this, just relaying stuff i read from the Applesauce discord
support channel. People ask questions like all of yours there all the time.
Join it and scroll back on that channel. Lotsa interesting stuff.
Sent from my iPhone
On Feb 27, 2024, at 15:43, Wayne S
<wayne.sudol(a)hotmail.com> wrote:
I know you do this for a living and are good at it. Most of us don’t do it as a living
but have piles of floppies that we want to recover cheaply using an existing method.
Grease, cat and other wezels, are fine but you have to do more work to get usable stuff,
unless your floppies are all c64 😀 The applesauce just seems further along than the
others.
Just my opinion.
Sent from my iPhone
> On Feb 27, 2024, at 15:33, CAREY SCHUG via cctalk <cctalk(a)classiccmp.org>
wrote:
>
> I knew most of this, which is why emulating the floppy controller should be
easier.
>
> applesauce is platform specific (ok, ANY floppy emulation will be platform specific
for apple)
>
> I thought the applesauce page said it was not yet available for standard shugart
style as in trs-80, s-100...
>
> greaseweasel is platform specific. the color coco is not yet available in the USA,
needing shipping from Europe, which in my experience is not cheap. not even promised for
trs80 1/3/4 or s-100. and are the parts cheap? dunno.
>
> did not know about gcr/mfm on same floppy...if you respond, please mention who does
that. gaak, I don't even
> recognize "gcr" at this point. I remember mfm and something else. mfm was
single density, right? was gcr
> double density? does not seem familiar, but certainly there was a double density
encoding scheme that the
> device attached to the floppy cable would have to recognize.
>
> I had forgotten that atari? commodore? changed speed, though I remember I knew that
before.
>
> <pre>--Carey</pre>
>
>>> On 02/27/2024 5:18 PM CST Wayne S via cctalk <cctalk(a)classiccmp.org>
wrote:
>>
>>
>> The “support” channel has the most info on the applesause.
>>
>>
>> Sent from my iPhone
>>
>>> On Feb 27, 2024, at 15:12, Wayne S <wayne.sudol(a)hotmail.com> wrote:
>>
>> Chuck, not to disagree much, because you are an expert, but there’s more to
decoding floppies than just reading them. Some floppies have tracks that are recorded at
different speeds. Some have tracks that use different modulation gcr on some and mfm on
others. A lot of floppies have different skew. The applesauce tries to handle these
problems and give you a readable file. It’s mostly in the software.
>>
>> I tried to send the discord link but don’t know if it got thru so here it is
again
>>
>> https://discord.gg/njetE8zU
>>
>> Wayne
>>
>>
>> Sent from my iPhone
>>
>>> On Feb 27, 2024, at 15:02, Chuck Guzis via cctalk
<cctalk(a)classiccmp.org> wrote:
>>
>> On 2/27/24 14:42, Wayne S via cctalk wrote:
>> Take a look at the Applesauce.
>> It hooks up to a lot of different floppy drives and records and decodes the
flux.
>> Version2 of the hardware is being sourced and should be available in a few
months.
>>
>> Good grief, there are more of these things floating around than one can
>> shake a stick at. The Greasweazel is perhaps the cheapest, using a $3
>> ($1.30 or so from Aliexpress) STM32F103 "Blue Pill" board.
>>
>> It's almost trivial doing this if you don't need the "eye
candy".
>> Basically you run a timer in capture mode, with capture triggered by an
>> edge on the drive's "read data" line.
>>
>> Modern MCUs don't even break a sweat doing this.
>>
>> It's nice seeing the proliferation after many years of harping on the
>> subject...
>>
>> --Chuck
28 Feb
28 Feb
12:01 a.m.
New subject: emulating floppies [was: Paper tape in casettes...]
On 2/27/24 15:43, Wayne S via cctalk wrote:
I know you do this for a living and are good at it.
Most of us don’t do it as a living but have piles of floppies that we want to recover
cheaply using an existing method. Grease, cat and other wezels, are fine but you have to
do more work to get usable stuff, unless your floppies are all c64 😀 The applesauce just
seems further along than the others.
Just my opinion.
To be fair, the OP was talking about replacing the WD disk controller.
As far as I know, WD 17xx and 27xx controllers can do FM and MFM. Heck,
they can't even do M2FM.
A small exception. Back in the 1970s, we did do GCR using the WD1781,
which is basically a 1771 without the modulation appendages. And even
then, it took a Multibus-sized board to implement the scheme.
--Chuck
12:12 a.m.
New subject: emulating floppies [was: Paper tape in casettes...]
On Tue, 27 Feb 2024, CAREY SCHUG via cctalk wrote:
did not know about gcr/mfm on same floppy...if you
respond, please mention who does that. gaak, I don't even
recognize "gcr" at this point. I remember mfm and something else. mfm was
single density, right? was gcr
double density? does not seem familiar, but certainly there was a double density
encoding scheme that the
device attached to the floppy cable would have to recognize.
Grossly oversimplified:
FM is Frequency Modulation, often called "single density".
There are clock pulses, and bit or no bit between the pulses, therefore,
strings of off bits look like one frewuency, and strings of on bits look
like another (double) frequency.
MFM is Modified Frequency modulation. when it came out, it was almost
double the capacity of FM, so the marketing people called it "double
density". It wasn't until after that naming that FM began to be called
"single density" (In a very similar way, if you look at old newspapers,
"World War 1" wasn't called that until the existence or spectre of
"World
War 2")
It was obvious that clock pulses weren't really needed between on bits.
By leaving those ones out, the average frequency/signal density was much
lower, making it possible to increase (typically double) the data transfer
rate. and thus almost twice the capacity per track.
GCR is Group Coded Record. Some patterns of bits are more "spread out"
than others. If you can find those, you could break up your 8 bit data
into 2 "nybbles" of 4 bits each, using only the nybbles that were spread
out enough to increase the data transfer rate, and squeeze more of those
pairs into the space that the 8 bit bytes had taken. If you can find 32
"loose" patterns, then you could record 5 bytes into 8 of those patterns.
A little extra firmware to do the conversion, but nothing horrendous.
Thus GCR typically would be about one and a half as much data per track
as FM,
GCR was used on Apple2, 400K/800K Mac, Commodore, Sirius/Vector, etc.
1.4M Mac is ordinary MFM, and can be done with WD style disk controllers.
Commodore Amiga was MFM, BUT, did not have the IBM/WD track and sector
structures; losing those, and reading a track at a time, and decoding that
into sectors in software permitted a little more capacity per track/disk.
In addition, on some hard drives, RLL (Run Length limited) is similar to
GCR.
Changing the motor speed or the data transfer rate for different tracks,
makes it easier to use different numbers of sectors, to put less data on
the small inner tracks, and more on the longer outer tracks. In order to
get closer to a standard linear velocity on the track, instead of a
standard angular velocity.
There are a few machines, such as Ensoniq, that would put multiple sizes
of sectors on a track! You can fit 5 1024 byte sectors on a track, but
not enough left for a sixth; however there was enough space for an
additional 512 byte sector.
There were more recording formats, such as MMFM, having FM sector
headers, with MFM sector content, etc.
The NEC 765 and its ilk are similar to WD 179x in capability, but with
important differences, including, WD has a "track read" command, NEC does
not but has a "multiple sector resd", NEC is "flash blinded" by the
index
pulse, and needs a little more time after index before reading, some NEC
controllers can't handle 128 byte MFM sector, many are implemented
without support for FM on the FDC board, . . .
--
Grumpy Ol' Fred cisin(a)xenosoft.com
12:15 a.m.
New subject: emulating floppies [was: Paper tape in casettes...]
CORRECTION:
GCR was used on Apple2, 400K/800K Mac, Commodore,
Sirius/Vector, etc.
That should read Victor 9000, NOT Vector [Graphics]
Vector Graphics was hard sectored, and not GCR.
Northstar is probably the best known of the hard sector formats.
6:46 p.m.
New subject: Paper tape in casettes...
On Tuesday, February 27th, 2024 at 13:30, ben via cctalk <cctalk(a)classiccmp.org>
wrote:
I had z80/s100 kit once, but the power supply failed
taking every thing out.
Ouch.
I think the PI is too cheap of computer build wise for
emulation
of any system. It might blink your lights, but never run 20 users
timesharing.
It depends on what they're doing. I've had twelve folks using a 3B+ as a regular
old
messing around server before. The microSD card wound up being the bottleneck. Anyway.
A good home brew computer is what I am looking for.
Like this, maybe?
https://rc2014.co.uk/
The Doctor [412/724/301/703/415/510]
WWW: https://drwho.virtadpt.net/
Don't be mean. You don't have to be mean.
27 Feb
27 Feb
9:49 p.m.
New subject: recreating old computers [was: Paper tape in casettes...]
Religion warning: I was a mainframer. Since at any practical budget, they can only be
emulated, for
small computers, I would like pure hardware as much as possible, and what did or could
have existed (no fpga).
What I wish somebody would create is an S-100 card (probably with a raspberry pie daughter
running
simulation for future upgradeability) that, initially emulates a complete Byte-8 or Imsai
computer
including memory and disk images on sdc cards, 24x40 display on an HDMI display and USB
keyboard.
serial and parallel ports emulated.
software upgrades could be:
-- a full web page with clickable front panels and ascii terminals.
-- support other CPU cards, e.g. 8088, 68000, 6502, etc
but the big thing:
bidirectional ports on all S-100 data lines. go into supervisory mode and define
--this memory range go to the s-100 bus so you can get that old 8k memory card working.
--this io range go to s-100 bus to get the old printer interface, etc going
--eventually down to just the CPU, pull this new card, put in old CPU and you have an
original.
--possibly reverse also, so would be super board emulating memory, disk, etc for an
original CPU card.
AND maybe headers to connect to ribbon cables to do the same functions to recover other
busses:
apple, TRS-80, OSI, unibus, isa, eisa, s-bus
<pre>--Carey</pre>
On 02/27/2024 2:13 PM CST Doug McIntyre via cctalk
<cctalk(a)classiccmp.org> wrote:
On Tue, Feb 27, 2024 at 11:10:34AM -0700, ben via cctalk wrote:
PS: With low cost Chinese PCB's and vintage
parts, why are people not
building real hardware replica's of interesting machines.
But they are..
I can't tell what you'd find interesting since the list is pretty wide.
I've got an Apple I replica board that someday I intend to populate and get running.
You've got the ReAmiga project producing new boards for using up old parts on broken
boards.
https://www.reamiga.info/?page_id=36
One thing that I find interesting (although I'd never do it), is a board to emulate
a 68000 CPU at much higher speeds running barebones emulator on a Raspberry Pi.
Aimed at Amiga A1200 again.
https://wiki.amiga.org/index.php?title=Pistorm32-Lite
I've put together my IMSAI 8080 frontpanel kit, with the CPU emulated on an ESP32.
https://thehighnibble.com/imsai8080/
Or they are about to ship out the PiDP-10 blinkenlights kits
https://obsolescence.dev/pidp10.html
The CPU again emulated on a RaPi, but all new boards and plastic for the console kit
I'm not sure if anybody has ever thought about making flipchip boards themselves
though.
Although they might have been..
https://forum.vcfed.org/index.php?threads/a-general-purpose-flip-chip-adapt…
10:09 p.m.
New subject: recreating old computers [was: Paper tape in casettes...]
On Feb 27, 2024, at 4:49 PM, CAREY SCHUG via cctalk
<cctalk(a)classiccmp.org> wrote:
Religion warning: I was a mainframer. Since at any practical budget, they can only be
emulated,
Depends on your definition of emulated. Is an FPGA version merely an
"emulation"? You might say yes if it's a functional model. Arguably no, if
it's a gate level model.
Suppose you had schematics of, say, a KA-10. You could turn those gates into VHDL or
Verilog, and that should deliver an exact replica of the original machine, bug for bug
compatible. That assumes the timing quirks are manageable, which for most machines should
be true. (It isn't for a CDC 6600.)
paul
10:52 p.m.
New subject: recreating old computers [was: Paper tape in casettes...]
On 2/27/24 14:09, Paul Koning via cctalk wrote:
Suppose you had schematics of, say, a KA-10. You
could turn those gates into VHDL or Verilog, and that should deliver an exact replica of
the original machine, bug for bug compatible. That assumes the timing quirks are
manageable, which for most machines should be true. (It isn't for a CDC 6600.)
A section manager from years ago mentioned to me that, as a fresh EE out
of school, his first job at CDC was measuring the loops of (taper pin)
wire on the 6600 to which Seymour had attached tags that said "tune".
--Chuck
28 Feb
28 Feb
1:16 a.m.
New subject: recreating old computers [was: Paper tape in casettes...]
On 2024-02-27 3:09 p.m., Paul Koning via cctalk wrote:
Dumpster diving is a 0 dollar budget.
People could afford the APPLE II, 8080 S-100 bus, SWTPC 6909. I assume
with careful shopping one can rebuild them for about the same price, in
small quanities.
Power supplies require harder to find parts.
Main frame rebuilding is costly, but I suspect the real cost is I/O
that can't be duplicated. A hardware emulation using microcode to me
is real computer, a windows fly by night emulation is not, as the base
platform is too unstable.
On Feb 27, 2024, at 4:49 PM, CAREY SCHUG via
cctalk <cctalk(a)classiccmp.org> wrote:
Religion warning: I was a mainframer. Since at any practical budget, they can only be
emulated,
Depends on your definition of emulated. Is an FPGA
version merely an "emulation"? You might say yes if it's a functional
model. Arguably no, if it's a gate level model.
I have bad luck with FPGA's, too many timing issues with routing.
I have better luck with a 2901 4 bit alu and some support logic mounted
on a small pcb.
Suppose you had schematics of, say, a KA-10. You
could turn those gates into VHDL or Verilog, and that should deliver an exact replica of
the original machine, bug for bug compatible. That assumes the timing quirks are
manageable, which for most machines should be true. (It isn't for a CDC 6600.)
paul
The IBM 1130 is also a pretty scary machine inside.
The blog is here.
https://rescue1130.blogspot.com/
Ben.
2:34 a.m.
New subject: recreating old computers [was: Paper tape in casettes...]
I'd say the real cost is the second or third system to get spare parts.
that is why I want to replace the WD chip. the microprocessor talks to it
at bus speed. the os knows it has to wait, though some waits are for the
wd chip to say it is done. a SIMPLE mod to the legacy OS can eliminate
those waits, thus IO as fast as a real hard disk, maybe as fast as an SSD.
I love the 1130, the only I/O instructions given to the printer are input.
And the 1620 does addition and multiplication by table lookup.
Again, even if somebody offered me a complete IBM model 30 with disk and
tape drives, I could not afford the shipping. would probably have to
take out the a window to get it inside (big expense), and it might
instantly become a basement installation. I'd have to have much more
power and A/C installed. And no spare parts. Now, any front panels...
Even recreations of front panels would be treasured. In the 1980s the
Bradford exchange had a 360/40 front panel mounted in their space with
lights artificially flashing. I might even attempt to modify an
emulator program to flash the lights appropriately.
<pre>--Carey</pre>
On 02/27/2024 7:16 PM CST ben via cctalk
<cctalk(a)classiccmp.org> wrote:
On 2024-02-27 3:09 p.m., Paul Koning via cctalk wrote:
Dumpster diving is a 0 dollar budget.
People could afford the APPLE II, 8080 S-100 bus, SWTPC 6909. I assume
with careful shopping one can rebuild them for about the same price, in
small quanities.
Power supplies require harder to find parts.
Main frame rebuilding is costly, but I suspect the real cost is I/O
that can't be duplicated. A hardware emulation using microcode to me
is real computer, a windows fly by night emulation is not, as the base
platform is too unstable.
On Feb 27, 2024, at 4:49 PM, CAREY SCHUG via
cctalk <cctalk(a)classiccmp.org> wrote:
Religion warning: I was a mainframer. Since at any practical budget, they can only be
emulated,
Depends on your definition of emulated. Is an
FPGA version merely an "emulation"? You might say yes if it's a functional
model. Arguably no, if it's a gate level model.
I have bad luck with FPGA's, too many timing issues with routing.
I have better luck with a 2901 4 bit alu and some support logic mounted
on a small pcb.
Suppose you had schematics of, say, a KA-10. You
could turn those gates into VHDL or Verilog, and that should deliver an exact replica of
the original machine, bug for bug compatible. That assumes the timing quirks are
manageable, which for most machines should be true. (It isn't for a CDC 6600.)
paul
The IBM 1130 is also a pretty scary machine inside.
The blog is here.
https://rescue1130.blogspot.com/
Ben. 
2:56 a.m.
New subject: recreating old computers [was: Paper tape in casettes...]
On 2/27/24 20:34, CAREY SCHUG via cctalk wrote:
Again, even if somebody offered me a complete IBM
model 30 with disk and
tape drives, I could not afford the shipping. would
A 360/30 could be a real problem. It used air bags to push
the microcode cards against the bit line boards. Those air
bags looked suspiciously like IV bags from the hospital. I
can't imagine they would still hold air after 50 years.
The 360/40 had mylar cards with flex-print to make the
microcode word lines, these were punched to break the lines
so they went either through, or around the sense
transformers to select a 1 or 0 for that bit. Old mylar
tends to crack, and I assume that would break the conductive
printing.
The 360/50 and /65 had capacitive microcode read only
storage which consisted of bit line boards with copper
squares and word line boards that had zig-zag word line
traces that had either the drive line or balance line
widened to cover the bit line square, to select 1 or 0.
These boards were separated by a 1 mil mylar sheet, and
squeezed by a spring-loaded metal plate and a foam pressure
spreader. I think these have at least a SLIGHT chance of
still working after 5 decades.
The power was not real high on these machines, although the
peripherals could draw a lot. The 360/50 and /65 CPUs drew
just a couple KW each.
Of course, the models /50 and /65 were a LOT bigger than a
/30, and much heavier. There's a reason people used to talk
about "big iron".
As for the logic, the 360's used SLT, a 1/2" square ceramic
hybrid with, generally two transistors, 4 diodes and 4
resistors per package. The complete schematics for all of
them are in the FEMM, and I'll bet one could replace them
with a tiny PCB with SOT23 transistors, etc. to replace any
bad modules.
Jon
3:53 a.m.
New subject: recreating old computers [was: Paper tape in casettes...]
On 2/27/24 18:34, CAREY SCHUG via cctalk wrote:
And the 1620 does addition and multiplication by table
lookup.
That was only the CADET; the Model II had the math hardcoded. There was
an octal arithmetic option for the Model II, so it could do binary math
of a sort. Spent lots of fun hours on a CADET with a 1311 disk drive.
--Chuck
5:02 a.m.
New subject: recreating old computers [was: Paper tape in casettes...]
our 1620 model 2 still did multiplication by table lookup.
<pre>--Carey</pre>
On 02/27/2024 9:53 PM CST Chuck Guzis via cctalk
<cctalk(a)classiccmp.org> wrote:
On 2/27/24 18:34, CAREY SCHUG via cctalk wrote:
And the 1620 does addition and multiplication by
table lookup.
That was only the CADET; the Model II had the math hardcoded. There was
an octal arithmetic option for the Model II, so it could do binary math
of a sort. Spent lots of fun hours on a CADET with a 1311 disk drive.
--Chuck 
6:44 a.m.
New subject: recreating old computers [was: Paper tape in casettes...]
Paul Koning wrote:
Suppose you had schematics of, say, a KA-10. You
could turn those
gates into VHDL or Verilog, and that should deliver an exact replica
of the original machine, bug for bug compatible. That assumes the
timing quirks are manageable
The mapping from asynchronous pulses, delay lines, etc, to VHDL or
Verilog isn't entirely straight forward. Still, it can be done, and
in the case of a KA10, it has. See https://github.com/aap/fpdpga
6:41 a.m.
New subject: recreating old computers [was: Paper tape in casettes...]
CAREY SCHUG wrote:
What I wish somebody would create is an S-100 card
(probably with a
raspberry pie daughter running simulation for future upgradeability)
that, initially emulates a complete Byte-8 or Imsai computer including
memory and disk images on sdc cards, 24x40 display on an HDMI display
and USB keyboard. serial and parallel ports emulated.
I believe this tick some of your boxes:
https://thehighnibble.com/imsai8080/
27 Feb
27 Feb
10:22 p.m.
New subject: Resurrecting old microcomputers
OK, probably the hardest part is the floppy disk, as the mechanics corrode over time
more than chips.
People have built electronics to connect to a floppy cable and emulate a drive
electronically. Difficult to catch the timing on flux changes and digitize.
More than I want to spend at this time.
Couldn't somebody more clever than me develop something that would plug into a
Western Digital floppy disk controller socket, catch the commands to the device directly?
Probably need to be an FPGA, to actively monitor and catch the bus signals.
Yes, and apple would have to have it's own, probably a card to plug into the bus.
Although I think I have an apple ][ 3rd party card what uses a WD controller and
standards shugart style drives. probably the disks are incompatible with those
from the apple ][ card, which is why I then bought a 3rd party apple style card
and disk (but did not do enough with any of them to remember details). IIRC there
was one other early PC that did not use WD floppy controller chips.
connect this wd emulator via USB to a modern tablet/desktop/smartphone where storage
and heavy lifting would be done.
With minimal changes to the original operating system, define floppy with at least
255 tracks of (?) at least 255 records of (?) 4096 bytes, effectively making
a hard disk, and of course as fast as it can transfer data. can't do that with
something grabbing signals off the floppy cable.
the emulation would initially be storing track images. Later it could understand
the floppy formats and actually store the data in PC files...shareable between Apple ][,
Atari, TRS-80 (all flavors), etc, etc, and the modern PC.
the WD emulator could emulate the original floppy controller also, so a computer could
have both the original mechanical floppy and modern high volume storage. That would
require
a clip to wherever the floppy select lines were stored.
28 Feb
28 Feb
12:29 a.m.
New subject: Resurrecting old microcomputers
On Feb 27, 2024, at 5:22 PM, CAREY SCHUG via cctalk
<cctalk(a)classiccmp.org> wrote:
OK, probably the hardest part is the floppy disk, as the mechanics corrode over time
more than chips.
People have built electronics to connect to a floppy cable and emulate a drive
electronically. Difficult to catch the timing on flux changes and digitize.
Not hard for floppies. Harder but still doable for MFM hard drives -- David Gesswein did
a very impressive version that's surprisingly inexpensive, using a BeagleBone Black or
Green as the control engine. I have one, it works perfectly.
paul
5:10 p.m.
New subject: Paper tape in casettes...
On 02/27/2024 2:13 PM CST Doug McIntyre via cctalk
<cctalk(a)classiccmp.org> wrote:
On Tue, Feb 27, 2024 at 11:10:34AM -0700, ben via cctalk wrote:
You might also want to have a look here:
http://www.s100computers.com/My%20System%20Index%20Page.htm
How about reproductions of "classic" S100 systems?
Or a Z180?
Or PDP-11 on S100?
or 486?
Will
Grownups never understand anything by themselves and it is tiresome for children to be
always and forever explaining things to them,
Antoine de Saint-Exupery in The Little Prince
PS: With low cost Chinese PCB's and vintage
parts, why are people not
building real hardware replica's of interesting machines.
But they are..
27 Feb
27 Feb
5:07 p.m.
New subject: Paper tape in casettes...
On 2/27/24 08:58, erik--- via cctalk wrote:
Hi Jon!
Yes, the cassette is visible right below where the tape is
coming out of the punch, Most other photos of the G-15 show
a shiny aluminum rectangle near the top front of the
computer. That is the cassette. There is a horizontal
lever across the cassette that holds it in place.
Jon
think the Bendix G-15 had cassettes for the
5-level tape
they used.
Aha, interesting! Did a short search, but have not been able to
find a picture of a casette. Just a pile of paper tape instead ;-)
https://images.app.goo.gl/HYqkpYHJUxZeGfiA8 
6:29 p.m.
New subject: Paper tape in casettes...
erik＠baigar.de wrote:
Bitsavers has a collection of G-15 manuals. For a picture of an open cassette, see PDF
page 27 in http://bitsavers.org/pdf/bendix/g-15/60061400_G15D_Parts_Manual.pdf.
Also see PDF page 18 in http://bitsavers.org/pdf/bendix/g-15/G15_Operating_Man_Jul59.pdf.
David Lovett has been restoring a G-15 for the System Source Computer Museum in Maryland
(US). He regularly publishes videos of his progress, such as this one:
https://www.youtube.com/watch?v=WNfR4DmoZQU&pp=ygUWYmVuZGl4IGctMTUgcGFw…
To see more, try searching youtube.com for "bendix g-15 paper tape".
think the Bendix G-15 had cassettes for the
5-level
tape
they used.
Aha, interesting! Did a short search, but have not been able to
find a picture of a casette. Just a pile of paper tape instead ;-)
https://images.app.goo.gl/HYqkpYHJUxZeGfiA8 
10:54 p.m.
New subject: Paper tape in casettes...
On 02/27/2024 12:29 PM CST paul.kimpel--- via cctalk
<cctalk(a)classiccmp.org> wrote:
Bitsavers has a collection of G-15 manuals.
Rob Kolstad (formerly of BSDI) and I sat down last August to categorize
his online scans. AFAICT he has the largest collection. (Of course
I forgot to bring my copy of the technical manual with all the waveforms
penciled in.) He and I need to get back to that project.
It had been a long time (high school days!) since I looked at that
doc.
To an experienced engineer, it's now clear how much of a work of genius
it was (so few gates!) No wonder I had trouble understanding it all
as a teenager.
David Lovett has been restoring a G-15 for the System
Source Computer Museum in Maryland (US).
Hmm. I don't remember if Rob told me about that project. He knows of
two in Texas.
Some of my old notes are at http://obscurecomputers.org/g15/index.html .
mcl
279
days inactive
280
days old
37 comments
15 participants
participants (15)
-
ben -
CAREY SCHUG -
Chuck Guzis -
Doug McIntyre -
erik＠baigar.de -
Fred Cisin -
Jon Elson -
Lars Brinkhoff -
Mark Linimon -
Martin Bishop -
Paul Koning -
paul.kimpel＠digm.com -
The Doctor -
Wayne S -
wrcooke＠wrcooke.net