7 Jan
2005
7 Jan
'05
7:52 a.m.
Hi
Most of these were designed such that a single
output pullup resistor didn't use all of the
sink of an output transistor. This means that
two outputs tied together and would not draw too much
current.
DTL does the same thing and allows the wired AND.
As I recall, with RTL, you only needed to apply
power to one device if they were inverters
since there was no other active logic,
like flops.
Dwight
From: "Steve Thatcher"
<melamy(a)earthlink.net>
I don't see how doing a wired-and is possible when RTL includes a pullup
resistor on each output. You would get to a point where an individual output
transistor would not be capable of sinking all the "low" current.
You can get a basic idea of the logic families here...
http://www.asic-world.com/digital/gates5.html
best regards, Steve Thatcher
-----Original Message-----
From: "Dwight K. Elvey" <dwight.elvey(a)amd.com>
Sent: Jan 7, 2005 12:22 PM
To: cctalk(a)classiccmp.org
Subject: RE: RTL Logic
Oops!
I forgot one thing. You can put several RTL outputs in
parallel as a wired AND. You can't do that with the
general CMOS or TTL. You'd need to look out for this.
Does anyone have a source for DTL parts. There are
a could I've been looking for.
Dwight
7 Jan
7 Jan
8:24 a.m.
It's funny to have a good discussion based on projects published over 30
years ago.
For the OP, modifying the original project to use currently available
devices, especially if you use devices that were contemporaneous seems OK to
me. I would not be surprised if people used 7404's or 7406's to build some
of these projects when they first came out.
I would be curious to know the reasoning of using RTL chips when TTL chips
were available considering they are driven out of spec, maybe Don was just
more comfortable with them or that is what he had laying around.
Randy
----- Original Message -----
From: "Dwight K. Elvey" <dwight.elvey(a)amd.com>
To: <cctalk(a)classiccmp.org>
Sent: Friday, January 07, 2005 12:52 PM
Subject: RE: RTL Logic
Hi
Most of these were designed such that a single
output pullup resistor didn't use all of the
sink of an output transistor. This means that
two outputs tied together and would not draw too much
current.
DTL does the same thing and allows the wired AND.
As I recall, with RTL, you only needed to apply
power to one device if they were inverters
since there was no other active logic,
like flops.
Dwight
From: "Steve Thatcher"
<melamy(a)earthlink.net>
I don't see how doing a wired-and is possible when RTL includes a pullup
resistor on each output. You would get to a point where an individual
output
transistor would not be capable of sinking all the "low" current.
>
>You can get a basic idea of the logic families here...
>
>http://www.asic-world.com/digital/gates5.html
>
>best regards, Steve Thatcher
>
>
>-----Original Message-----
>From: "Dwight K. Elvey" <dwight.elvey(a)amd.com>
>Sent: Jan 7, 2005 12:22 PM
>To: cctalk(a)classiccmp.org
>Subject: RE: RTL Logic
>
>Oops!
> I forgot one thing. You can put several RTL outputs in
>parallel as a wired AND. You can't do that with the
>general CMOS or TTL. You'd need to look out for this.
> Does anyone have a source for DTL parts. There are
>a could I've been looking for.
>Dwight 
8:44 a.m.
On Fri, 7 Jan 2005, Randy McLaughlin wrote:
I would be curious to know the reasoning of using RTL
chips when TTL chips
were available considering they are driven out of spec, maybe Don was just
more comfortable with them or that is what he had laying around.
Cost! TTL was pricey when new, and RTL was last year's model,
available as surplus.
4:30 p.m.
On Fri, 7 Jan 2005 13:24:08 -0600
"Randy McLaughlin" <randy(a)s100-manuals.com> wrote:
It's funny to have a good discussion based on
projects published over
30 years ago.
For the OP, modifying the original project to use currently available
devices, especially if you use devices that were contemporaneous seems
OK to me. I would not be surprised if people used 7404's or 7406's to
build some of these projects when they first came out.
I would be curious to know the reasoning of using RTL chips when TTL
chips were available considering they are driven out of spec, maybe
Don was just more comfortable with them or that is what he had laying
around.
Randy
Don Lancaster is still online, so if anybody wants, they could ask him
directly, by emailing. He also has a phone-for-any-question kind of
thing set up, with a published number you can call.
His website is http://www.tinaja.com
He appears to be mostly into non-electronic stuff these days. A lot of
eBay marketing.
-Scott
5:51 p.m.
I used his site to point to some humor he wrote about inverters in a
previous post.
Randy
----- Original Message -----
From: "Scott Stevens" <chenmel(a)earthlink.net>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk(a)classiccmp.org>
Sent: Friday, January 07, 2005 9:30 PM
Subject: Re: RTL Logic
On Fri, 7 Jan 2005 13:24:08 -0600
"Randy McLaughlin" <randy(a)s100-manuals.com> wrote:
It's funny to have a good discussion based on
projects published over
30 years ago.
For the OP, modifying the original project to use currently available
devices, especially if you use devices that were contemporaneous seems
OK to me. I would not be surprised if people used 7404's or 7406's to
build some of these projects when they first came out.
I would be curious to know the reasoning of using RTL chips when TTL
chips were available considering they are driven out of spec, maybe
Don was just more comfortable with them or that is what he had laying
around.
Randy
Don Lancaster is still online, so if anybody wants, they could ask him
directly, by emailing. He also has a phone-for-any-question kind of
thing set up, with a published number you can call.
His website is http://www.tinaja.com
He appears to be mostly into non-electronic stuff these days. A lot of
eBay marketing.
-Scott 
7:23 p.m.
New subject: Imlac PDS-1 simulators?
Does anyone knows about of any Imlac PDS-1 simulators? I've taken a
real interest in them recently, and I think it might be a fun project
to participate in. I very sincerely doubt that I have the motivation
to tackle the entire thing myself, so I'm hoping one has already
been started by somebody with a more gung-ho attitude than I have :)
I'm also looking for PDS-1 software -- does anyone have any archived
somewhere where it can be downloaded?
-Seth
--
"It looks just like a Telefunken U47! Seth Morabito
You'll love it." - Frank Zappa sethm(a)loomcom.com
7:40 p.m.
New subject: Imlac PDS-1 simulators?
On Fri, 7 Jan 2005, Seth Morabito wrote:
Does anyone knows about of any Imlac PDS-1 simulators?
I've taken a
real interest in them recently, and I think it might be a fun project
to participate in. I very sincerely doubt that I have the motivation
to tackle the entire thing myself, so I'm hoping one has already
been started by somebody with a more gung-ho attitude than I have :)
I'm also looking for PDS-1 software -- does anyone have any archived
somewhere where it can be downloaded?
DigiBarn has Maze War:
http://www.digibarn.com/history/04-VCF7-MazeWar/
I have it too, but it's easier to get it from DigiBarn ;)
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
7:41 p.m.
New subject: Imlac PDS-1 simulators?
Just recently PDS software was offered and I posted it on my site.
Also available are some Intel emulators for ISIS (not PDS and not full
system emulators).
Randy
www.s100-manuals.com
Also directly accessed via http://intel.s100-manuals.com
----- Original Message -----
From: "Seth Morabito" <sethm(a)loomcom.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk(a)classiccmp.org>
Sent: Saturday, January 08, 2005 12:23 AM
Subject: Imlac PDS-1 simulators?
Does anyone knows about of any Imlac PDS-1 simulators? I've taken a
real interest in them recently, and I think it might be a fun project
to participate in. I very sincerely doubt that I have the motivation
to tackle the entire thing myself, so I'm hoping one has already
been started by somebody with a more gung-ho attitude than I have :)
I'm also looking for PDS-1 software -- does anyone have any archived
somewhere where it can be downloaded?
-Seth
--
"It looks just like a Telefunken U47! Seth Morabito
You'll love it." - Frank Zappa sethm(a)loomcom.com
8 Jan
8 Jan
5:49 a.m.
New subject: Imlac PDS-1 simulators?
On Sat, 8 Jan 2005, Randy McLaughlin wrote:
Just recently PDS software was offered and I posted it
on my site.
Not Intel PDS, Imlac PDS ;)
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
4:51 a.m.
New subject: Imlac PDS-1 simulators?
At 10:23 PM 1/7/2005 -0800, Seth Morabito wrote:
Does anyone knows about of any Imlac PDS-1 simulators?
I've taken a
real interest in them recently, and I think it might be a fun project
to participate in. I very sincerely doubt that I have the motivation
to tackle the entire thing myself, so I'm hoping one has already
been started by somebody with a more gung-ho attitude than I have :)
I'm also looking for PDS-1 software -- does anyone have any archived
somewhere where it can be downloaded?
I've been considering starting a simulator project for the PDS-1D, but
haven't actually engaged yet. You can find some code and related info
on my site:
http://www.ubanproductions.com/imlac.html
http://www.ubanproductions.com/imlac_sw.html
--tom
5:54 a.m.
New subject: Imlac PDS-1 simulators?
On Sat, 8 Jan 2005, Tom Uban wrote:
I've been considering starting a simulator project
for the PDS-1D, but
haven't actually engaged yet. You can find some code and related info
on my site:
http://www.ubanproductions.com/imlac.html
http://www.ubanproductions.com/imlac_sw.html
Tom, AWESOME! Thanks for putting all that stuff on the web. I didn't
realize you had so much software for the Imlac.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
9:01 a.m.
New subject: Imlac PDS-1 simulators?
On Sat, Jan 08, 2005 at 09:51:20AM -0600, Tom Uban wrote:
I've been considering starting a simulator project for the PDS-1D, but
haven't actually engaged yet. You can find some code and related info
on my site:
http://www.ubanproductions.com/imlac.html
http://www.ubanproductions.com/imlac_sw.html
Wow! I knew about your imlac hardware page, but I hadn't seen your
software and docs page before. This is fantastic, thanks!
--tom
-Seth
--
"It looks just like a Telefunken U47! Seth Morabito
You'll love it." - Frank Zappa sethm(a)loomcom.com
1:11 p.m.
New subject: Imlac PDS-1 simulators?
At 12:01 PM 1/8/2005 -0800, you wrote:
On Sat, Jan 08, 2005 at 09:51:20AM -0600, Tom Uban
wrote:
Heh! Been there for a while, hiding under the "here" link at the top.
--tom
I've been considering starting a simulator project for the PDS-1D, but
haven't actually engaged yet. You can find some code and related info
on my site:
http://www.ubanproductions.com/imlac.html
http://www.ubanproductions.com/imlac_sw.html
Wow! I knew about your imlac hardware page, but I hadn't seen your
software and docs page before. This is fantastic, thanks! 
19 Jan
19 Jan
11:16 p.m.
New subject: Imlac PDS-1 simulators?
On Sat, Jan 08, 2005 at 09:51:20AM -0600, Tom Uban wrote:
Nice pix, especially http://www.ubanproductions.com/Images/imlac11.jpg
It bears a striking resemblance to the core stack in an PDP-8/L or
PDP-8/i (those, of course, are either 4096x12 or 4096x13, depending on
parity. Even the fingers look like DEC spacing.
I am unfamiliar with the Imlac line... why would there be such
similarities? Dataram already have something handy?
-ethan
20 Jan
20 Jan
6:03 a.m.
New subject: Imlac PDS-1 simulators?
At 05:16 AM 1/20/2005 -0500, you wrote:
On Sat, Jan 08, 2005 at 09:51:20AM -0600, Tom Uban
wrote:
Nice pix, especially http://www.ubanproductions.com/Images/imlac11.jpg
It bears a striking resemblance to the core stack in an PDP-8/L or
PDP-8/i (those, of course, are either 4096x12 or 4096x13, depending on
parity. Even the fingers look like DEC spacing.
I am unfamiliar with the Imlac line... why would there be such
similarities? Dataram already have something handy?
I'd guess because they could get the core module more cheaply if they
used something at least semi-standard. Also, Imlacs were designed and
built in Waltham MA, probably be ex-Dec people...
--tom
7:04 a.m.
New subject: Imlac PDS-1 simulators?
On Thu, Jan 20, 2005 at 11:03:43AM -0600, Tom Uban wrote:
At 05:16 AM 1/20/2005 -0500, you wrote:
I'd guess because they could get the core module more cheaply if they
used something at least semi-standard. Also, Imlacs were designed and
built in Waltham MA, probably be ex-Dec people...
I didn't know they were in Waltham! Neat, I lived there for a year.
(It's probably only "neat" to me because I'm a west coast boy)
I've made startlingly little progress on my stab at a PDS-1 simulator,
but at least I have a working environment stubbed out. Thanks to
Bob Supnik's fantastic SIMH framework, it was amazingly easy to
throw together a new, empty simulator and start implementing it.
I haven't used C in a number of years, so I'm a little rusty, but
it's all pouring back. Like riding a bike.
--tom
-Seth
--
"It looks just like a Telefunken U47! Seth Morabito
You'll love it." - Frank Zappa sethm(a)loomcom.com
7:47 a.m.
New subject: Imlac PDS-1 simulators?
Interesting all the talk Imlac gets on the list and
nothing for either Adage or Evans & Sutherland.
Guess it didn't hurt the programmer's console
was such a prominent part of the Imlac.
John A.
10:14 a.m.
New subject: Imlac PDS-1 simulators?
On Thu, 20 Jan 2005, John Allain wrote:
Interesting all the talk Imlac gets on the list and
nothing for either Adage or Evans & Sutherland.
Guess it didn't hurt the programmer's console
was such a prominent part of the Imlac.
I think mainly because machines from either manufacture are difficult to
find. Same with the Imlac, but it just so happens a few people here (Bob
Shannon, Tom Uban, and myself, plus one other Bob/Robert that used to be
on the list) are fortunate to have come into possession of the very few
still existing.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
22 Jan
22 Jan
3 a.m.
New subject: Imlac PDS-1 simulators?
There is a fourth Imlac around!?
Does anyone know the state and condition of this other Imlac?
FYI, the Imlac CPU is quite different from the PDP-8, but it does
have many similarities such as the auto-index register locations in
memory, etc.
But being a 16-bit CPU the page size is different (2K words), and
the Imlac has some slightly unusual 11-bit literal instructions (load
with n, and load with complement of n). I don't think those are found
on the -8.
There are some similarities between the Imlac's main CPU and
the HP1000 processors, but this is deceiving, many instruction codes
are the same or similar, but the auctual operations have some differences.
(Dymec studied the -8 when they developed the 2116, but the HP has
additional registers and many more instructions than the -8, or PDS-1).
Moving from HP assembler to Imlac assembler is tricky, its similar but
very different. Becuase of the simplicity of the Imlac CPU it probably
is more -8 like than the HP, despite the direct link between the HP and
-8.
----- Original Message -----
From: "Vintage Computer Festival" <vcf(a)siconic.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk(a)classiccmp.org>
Sent: Thursday, January 20, 2005 4:14 PM
Subject: Re: Imlac PDS-1 simulators?
On Thu, 20 Jan 2005, John Allain wrote:
Interesting all the talk Imlac gets on the list
and
nothing for either Adage or Evans & Sutherland.
Guess it didn't hurt the programmer's console
was such a prominent part of the Imlac.
I think mainly because machines from either manufacture are difficult to
find. Same with the Imlac, but it just so happens a few people here (Bob
Shannon, Tom Uban, and myself, plus one other Bob/Robert that used to be
on the list) are fortunate to have come into possession of the very few
still existing.
--
Sellam Ismail Vintage Computer
Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger
http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage
mputers ]
[ and academia at www.VintageTech.com || at
http://marketplace.vintage.org ]
8:10 a.m.
New subject: Imlac PDS-1 simulators?
Bob wrote:
the Imlac has some slightly unusual 11-bit literal
instructions (load
with n, and load with complement of n). I don't think those are found
on the -8.
No, but they are found on a PDP-1. Maybe the IMLAC designers were picking
features they liked from multiple DEC machines.
12:27 p.m.
New subject: wtd: apple profile drive
Hi,
Does anyone in the UK have an apple profile external drive unit, working,
5MB or 10MB - needed to complete a Lisa restoration project.
Cheers,
Stu
25 Jan
25 Jan
5:39 a.m.
New subject: Imlac PDS-1 simulators?
On Sat, 22 Jan 2005, Bob Shannon wrote:
There is a fourth Imlac around!?
Does anyone know the state and condition of this other Imlac?
I promised Tom Uban I'd try to remember the name of the person who has it,
but yes. He used to be a list dweller. I got all my documentation from
him. He sent over a box of manuals and I made photocopies before sending
it back.
Ok, just went through saved messages and it was John Tinker. I still have
his contact info.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
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20 Jan
20 Jan
7:40 a.m.
New subject: Imlac PDS-1 simulators?
On Thu, 20 Jan 2005, Tom Uban wrote:
At 05:16 AM 1/20/2005 -0500, you wrote:
I've been told the Imlac processor is based on the PDP-8, or that it has
the same instructions as the PDP-8. I wouldn't know because I've never
programmed either.
Some info to this effect here:
http://www.blinkenlights.com/classiccmp/imlac/
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
On Sat, Jan 08, 2005 at 09:51:20AM -0600, Tom Uban
wrote:
Nice pix, especially http://www.ubanproductions.com/Images/imlac11.jpg
It bears a striking resemblance to the core stack in an PDP-8/L or
PDP-8/i (those, of course, are either 4096x12 or 4096x13, depending on
parity. Even the fingers look like DEC spacing.
I am unfamiliar with the Imlac line... why would there be such
similarities? Dataram already have something handy?
I'd guess because they could get the core module more cheaply if they
used something at least semi-standard. Also, Imlacs were designed and
built in Waltham MA, probably be ex-Dec people... 
9:05 a.m.
New subject: Imlac PDS-1 simulators?
Vintage Computer Festival wrote:
I've been told the Imlac processor is based on the PDP-8, or that it has
the same instructions as the PDP-8. I wouldn't know because I've never
programmed either.
Some info to this effect here:
http://www.blinkenlights.com/classiccmp/imlac/
I don't know much about Imlacs, and I'm probably younger than most
PDP-8s ever built (1973?) - but from the photos of the programmer's
console of an Imlac it looks like it's 16 bit. So, (probably) not very
closely based on a PDP-8 then.
Gordon.
22 Jan
22 Jan
2:46 a.m.
New subject: Imlac PDS-1 simulators?
Imlac PDS-1's used third-party memory modules. There are at least two
vendors.
The Imlac Sellam has uses what Imlac called MEM-1, and it has a large
cannon connector on the memory backplane.
My Imlac used MEM-2, where all the connections to the processors
are made with wire-wrap.
MEM-2 core modules don't have parity bits.
----- Original Message -----
From: "Ethan Dicks" <ethan.dicks(a)gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk(a)classiccmp.org>
Sent: Thursday, January 20, 2005 5:16 AM
Subject: Re: Imlac PDS-1 simulators?
On Sat, Jan 08, 2005 at 09:51:20AM -0600, Tom Uban
wrote:
Nice pix, especially http://www.ubanproductions.com/Images/imlac11.jpg
It bears a striking resemblance to the core stack in an PDP-8/L or
PDP-8/i (those, of course, are either 4096x12 or 4096x13, depending on
parity. Even the fingers look like DEC spacing.
I am unfamiliar with the Imlac line... why would there be such
similarities? Dataram already have something handy?
-ethan
7 Jan
7 Jan
7:53 p.m.
At 09:30 PM 1/7/2005, Scott Stevens wrote:
His website is http://www.tinaja.com
He appears to be mostly into non-electronic stuff these days. A lot of
eBay marketing.
Ah, Don - always entertaining. His auction tips within his eBay
tips have many nuggets of value to anyone hunting classic equipment
as well as those re-sellable modern nuggets that can fund the
old-computer habit.
His eBay seller tips seem to be aimed at people who want to make
a living at it. I balked at his 30:1 tip, for example, having
derived that I was happy with a 10:1 ratio on items I bought
for $100. Then you read things like his recommendation that you
spend at least two hours cleaning up an image for an eBay auction,
or his Rube Goldberg methods to do image processing in PostScript,
and you wonder if he's spent a little too much time at high altitudes.
- John
8 Jan
8 Jan
8:51 a.m.
On Fri, 7 Jan 2005, Scott Stevens wrote:
Don Lancaster is still online, so if anybody wants,
they could ask him
directly, by emailing. He also has a phone-for-any-question kind of
thing set up, with a published number you can call.
His website is http://www.tinaja.com
I've called him, in the past, about his flutterwumper stuff. (I
made a box that drives a Tek 555 storage scope... with
PostScript.)
He's a total nut. THat's not a put down, we need more nuts like
him. What have normal people done for the world?
10:08 a.m.
On Sat, 8 Jan 2005, Tom Jennings wrote:
On Fri, 7 Jan 2005, Scott Stevens wrote:
He and Wayne Green should get together and tour the country doing a freak
show.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
Don Lancaster is still online, so if anybody
wants, they could ask him
directly, by emailing. He also has a phone-for-any-question kind of
thing set up, with a published number you can call.
His website is http://www.tinaja.com
I've called him, in the past, about his flutterwumper stuff. (I
made a box that drives a Tek 555 storage scope... with
PostScript.)
He's a total nut. THat's not a put down, we need more nuts like
him. What have normal people done for the world?
7153
days inactive
7171
days old
28 comments
14 participants
participants (14)
-
allain＠panix.com -
bshannon＠tiac.net -
chenmel＠earthlink.net -
dwight.elvey＠amd.com -
eric＠brouhaha.com -
ethan.dicks＠gmail.com -
gordon＠gjcp.net -
jfoust＠threedee.com -
randy＠s100-manuals.com -
sethm＠loomcom.com -
stuart＠zen.co.uk -
tomj＠wps.com -
uban＠ubanproductions.com -
vcf＠siconic.com