There is a guy in Portland Oregon that has a lot of old DG. I will see if I
can try to contact him next time in Portland, in a week or two. I think he
has some 6045s.
Just thinking about him I realize he spends some of the winter in Thailand.
Hope he wasn't involved in the Tsunami.
Paxton,
Astoria, OR
Hey guys...
I have a line on a Convex machine. The current owner is a guy
who attends Govt. auctions and buys bulk, then scraps out stuff for
gold/parts/etc... He calls me when he finds anything interesting, so...
He says this is a Convex SPP3. (it's _heavy_... around 400 Lbs.) I
haven't seen it yet, so I don't know anything more right now.
Unfortunately,
I have no knowledge of Convex stuff, and a web search turned up some
Convex SPP stuff, but not much, and _nothing_ on an "SPP3". Can anyone
enlighten me further? (Yep, I know it's an SMP architecture of some sort,
but
little more than that).
A couple of questions...
Is this machine historically significant? (I.e. worth saving?)
Does anyone know of a source for documentation? (I've done a prelim.
web/newsgroup
search, but haven't turned anything up)
Does anyone have (or know where I can find) a copy of an OS for it
(apparently
it's a unix variant. He told me that the disks were missing... not unusual
for an auction item)
400 lbs is a bit large for me, but if there is a remote chance I can bring
this
critter back to life (and it's worth saving) it's probably worth the effort.
I'll going to
try to take a look at it and try to get some sort of model#/ident. Anything
I should
be looking out for or wary of?
-al-
-acorda(a)1bigred.com
yes, and you are pointing out a three input dual NOR gate. You said several could be paralleled. What you pointed out in the book was text that said you could connect two together...
-----Original Message-----
From: "Dwight K. Elvey" <dwight.elvey(a)amd.com>
Sent: Jan 7, 2005 2:13 PM
To: cctalk(a)classiccmp.org
Subject: RE: RTL Logic
Hi
If you look at Al's spec page, see 017_MC715 or page 18.
It states:
Each may be used independently, paralleled for increasing
the number of inputs ( subject to loading rules), or
cross-coupled to form bistable elements.
So, as you can see, it was allowed to tie outputs together
with some restrictions.
Dwight
The MC789 is a hex inverter, a 7404 or 7406 could be used but the pin-out is
different
--
The only thing it has in common with a TTL inverter is the function it performs.
RTL logic, power supply, and switching performance are NOT the same as TTL.
I have the RTL section of the 1969 Motorola microelectronics catalog scanned
I'll see about getting it on line later today.
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
Hi
RTL is 3.6V. You could get by with CMOS but
not TTL, directly. Of course, you could run two
power rails. The signal levels of RTL and TTL are
somewhat compatable.
Dwight
>From: "Cini, Richard" <RCini(a)congressfinancial.com>
>
>OK, this might sound like a stupid question, but being somewhat ignorant of
>RTL logic in comparison to TTL and other designs, what, if anything, can be
>substituted for RTL logic chips?
>
>For example, if I wanted to build one of Don's devices and I wasn't
>concerned with using "vintage" chips, could I do it "plug-and-play" using
>current TTL?
>
>Rich
>
>-----Original Message-----
>From: cctalk-bounces(a)classiccmp.org
>[mailto:cctalk-bounces@classiccmp.org]On Behalf Of Michael Holley
>Sent: Friday, January 07, 2005 12:08 AM
>To: cctalk(a)classiccmp.org
>Subject: RTL Logic
>
>
>I have acquired some Don Lancaster designs that use RTL logic and I am
>looking for spare parts. The MC789 hex inverter is used in all of them and I
>have 2 chips. Does anyone have a reasonable source for the MC789, I can get
>all I want for $20 a chip.
>
>I also have 2 MC799 buffers that are use in the Microlab. I have found two
>each of these (MC725, MC778, MC785, MC792, MC853, MC855) that I will part
>with.
>
>SWTPC Digital Logic Microlab
>http://www.swtpc.com/mholley/PopularElectronics/Apr1970/PE_Apr1970.htm
>Early SWTPC keyboard
>http://www.swtpc.com/mholley/PopularElectronics/Apr1974/PE_Apr1974.htm
>
>I think that Don Lancaster's TIC TAC TOE machine from 1971 is a very clever
>design. It uses 5 ICs and 60 diodes to play the game. I may build one.
>http://www.swtpc.com/mholley/RadioElectronics/Dec1971/RE_Dec1971.htm
>
>Michael Holley
>www.swtpc.com/mholley
>
>
Hi
There may be a good reason for his selection. It may
have been the pull-up voltage he needed since TTL
is voltage limited on output swing. It may have been
the sink current as well. One really needs to check
the actual useage to see what he had in mind. I'm sure
the application would show what the issue was.
Dwight
>From: "Randy McLaughlin" <randy(a)s100-manuals.com>
>
>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
>
>
>
Hi
If you look at Al's spec page, see 017_MC715 or page 18.
It states:
Each may be used independently, paralleled for increasing
the number of inputs ( subject to loading rules), or
cross-coupled to form bistable elements.
So, as you can see, it was allowed to tie outputs together
with some restrictions.
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
>
>
>
