Re: General public machines (Was: Altair 8800 name Was: Re: Altair 680 Expansion Boards?

[drlegendre .]

@Grumpy Old Fred

I knew my last missive would provoke at least one or two interesting (if
not informative) responses. Yours was no exception, and I thank you for it.

For one, I hadn't known that CP/M was written originally to the 8080.. I'd
always assumed it originated on the Z80. And I don't doubt that RS / TRS-80
held a large share (until 1982 or so..) of the home computer market.

At the time, I was in my (almost) young teens - and at least in the circles
I traveled, the TRS-80 / Osborne and Kaypro were viewed as boring, stodgy
machines without any redeeming entertainment qualities - no color graphics,
no sprites, poor or nearly non-existent audio, expensive joysticks and so
on.

The ability of the machines to serve multiple roles - for both 'serious'
work and video gaming / music - was a huge selling point in the early days.
This is one of the reasons that the C64 was so massively successful - it
pretty much had something for everyone, as the saying goes. That, and the
price of the base machine was just amazingly low for the time. Ditto for
the VIC-20.

On Thu, Dec 22, 2016 at 10:04 PM, Fred Cisin  wrote:

> We all hang out with people who are smart enough to see things the same
> way that we do.  Accordingly, our choices in computers, cars, cellphone
> providers always look to us like the MAJORITY.   They are the BEST, and
> certainly the MOST POPULAR [among everybody that WE hang out with], but not
> necessarily the best selling.
>
> If the world were just, and the BEST outsold the worst, then we would all
> be using Amiga :-)
>
>
> On Thu, 22 Dec 2016, drlegendre . wrote:
>
>> "The Z80 had more players and more names than all the rest"
>> And yet it was essentially a bit-player in the days of the 'home computer'
>> revolution - at least in the US. CBM, Apple, Atari - the three big names
>> in
>> home computers, all went with the 6502 family. And perhaps even more
>> importantly, so did Nintendo, in the NES.
>>
>
> And yet, somehow, z80 was outselling 6502!
>
> http://jeremyreimer.com/m-item.lsp?i=137
>
> Radio Shack, TRS-80, WAS one of the "three big names".  It had a
> not-insignificant share of the market, and until 1982 was the best
> selling.  Don't ignore the impact of having incompetents peddling in
> thousands of store, in every city and town!
> Atari took a while longer to get market share.
> http://www.trs-80.org/was-the-trs-80-once-the-top-selling-computer/
>
> At the same time.
> Depending on how you define "first" ("first" to show V "first" to ship V
> "first" to be available for shelf purchase) will define whether Apple,
> Commodore, or Radio Shack was "the first".  It is trivially esay to select
> a definition of "first" to make it your choice of those.   Apple was the
> first of those announced and shown.
> I bought a TRS-80 ($400 (or $600 if you wanted their composite monitor and
> cassette player)) because it was the first one [by multiple months] that I
> could walk in the door of a local store and buy one.  The more appealing
> Apple, which had been announced earlier that TRS-80, was hard to come by
> for several more months.
>
> That time differential of months seems inconsequential 40 years later, but
> it mattered to me right then.  And, for most rational measures, Apple,
> TRS-80 and Commodore initial releases were a tie.
> (Was the photo finish by a nose, a whisker, or a hoof?)
> When the 5150 came out in August 1981, it was months before I could
> actually get one.
>
> AFTER the 5150 came out, people relized that TRS-80 was doomed, and in
> 1982, Apple 2 finally started to outsell TRS-80.  It was LESS obvious that
> Apple 2 was doomed.  But, within Apple, they knew there were troubled times
> ahead, and came out with the disastrous Apple 3, and disastrous [from point
> of view of SALES] Lisa.
>
> 'Course IBM poisoned the market for everything else, and nothing else sold
> like IBM.   On August 12, 1981, I said "In 10 years, 3/4 of the market will
> be IBM PC and imitations of it."
> It is amazingly impressive that Apple (Mac) survived IBM!
> (If you think that Mac outsold PC, then you are looking at YOUR circle,
> and need to look at actual sales numbers)
> But, by the time that the Mac came out, TRS-80 was finally becoming that
> "bit player" that some assume that it was, or should have been.
>
> The main use of Z80 in US home
>> computing was in the absurdly small Timex / Sinclair ZX80 series - with
>> their awful cramped membrane keyboards and seriously limited sound &
>> video.
>>
> Which was years later, and WAS a bit player and absurdly small. It was
> NEVER the main use of Z80 in USA home computing.  TRS-80 outsold them more
> than 100 to 1.
> Was that really a membrane keyboard, or was it just a PICTURE of a
> keyboard as a recommendation, like the "part of this complete breakfast".
>
> The Z80 also showed up in the Osborne, Kaypro and TRS-80 models.. mostly
>> due to the fact that CP/M was written to it. Commodore also put one in the
>> C128, 

Re: General public machines (Was: Altair 8800 name Was: Re: Altair 680 Expansion Boards?

[John Labovitz]

I’ll chime in on the Z80 preference, since I was there at the time. In the very 
early 1980s, when I was about 15, my father decided to buy a home computer. 
(Before that, he had a TI Silent 700 that dialed up to a Univac mainframe.) I 
remember him doing hours of research comparing the Apple II, the TRS-80, the 
Commodore PET, and probably some of the S-100 machines. He eventually chose the 
Heathkit H89. I’ll have to ask him exactly why, but I know that he’s always 
liked good-quality tools, and the combination of the Heathkit design, the Z80 
CPU, and CP/M seemed like the best combination of tools at the time.

I think it was probably a bit like the current perception of Apple’s hardware: 
expensive, but well-built and well-designed (minus some of the latest 
missteps). The other ‘lesser’ machines seemed far clunkier (excepting the S-100 
stuff). I did some Z80 assembly when I was a kid, and even the notation of that 
language seemed clearer, more zen-like, than the 8080, and certainly than the 
6502. Sorry to say, but when I hung out with friends who had Apple IIs, I 
always found their 40-character display mighty lacking… TRS-80s were fun to 
play with (and I did frequently at the local Radio Shack), but seemed much more 
oriented towards either simple BASIC programming, or business use — pretty 
boring for a 15-year old. ;)

CP/M, too, at least *seemed* more connected to the minicomputer world. We had a 
variety of assemblers and compilers; I learned C, assembly, LISP (well, not 
really), BASIC, word processors — and via our 300-baud modem, dialed up to the 
ARPAnet. Not to say that one couldn’t do that with the other machines, but even 
at the time, the Heathkit with CP/M seemed more of what we’d now call ‘server 
class.’ In fact, I ran a BBS for a year or two on that machine, with 
hand-rolled messaging software in BASIC, and the BYE software to handle the 
magic of dial-up access to a microcomputer.

Finally, the Heathkit was — not surprisingly — a kit. As a teenager, I I 
soldered together two or three H89s, several H19 terminals, and at least one 
printer; that experience taught me *so much* about the physical workings of 
computers.

—John

Re: General public machines (Was: Altair 8800 name Was: Re: Altair 680 Expansion Boards?

[Fred Cisin]

NO source is completely reliable.



http://jeremyreimer.com/m-item.lsp?i=137

http://jeremyreimer.com/uploads/notes-on-sources.txt

He does provide some information on his sources.

When we talk about sales, are we talking about UNITS, or about dollars?
(an important distinction for such as the ZX80 V anything else!)


His curve fitting is flawed.  For example, in his 1975 to 1981 graph, he 
has points for sales of TRS-80 of ZERO in 1976, and LOTS in 1977.  But, 
then he just drew a straight line, which erroneously implies a linear 
increase, with sales in 1976.  THAT derivative should be a vertical line, 
not a slope, unless/until you add more resolution for months, instead of 
years, representing an extremely steep slope in the end of 1977.


At least his last graph leaves off the "USA Today" fill in graphics, and 
shows the individual data points.  Which, I'm pleased to say, show C64 
outselling ANYTHING ELSE for a couple of years.
But, the vertical scale??  That's 100% of WHAT?  If it were percentage of 
market share, then it should TOTAL to 100% each year, albeit with a 
significant "Other" category.  ("Other" is approximately "PC Share" 
inverted from the 50% line?)



Does anybody know of a BETTER source for sales numbers?



Again, "everybody/MOST uses/used" doesn't work.
But, "everybody/MOST who knew what they were doing" does.

Re: ADM-3A Lower case ROM issue

[Eric Smith]

>From the ADM3A Maintenance Manual, page 6-11:

The two character generator ROMs are rather straightforward. The upper case
> ROM is a standard masked part (2513) but the lower case ROM is a custom
> masked part. The one unusual thing about this is that all of the address
> lines into the lower case character generator are inverted.
>

That refers to the character code address inputs to the ROMs; the line
address is common between the two.

The character addresses for the ROMs come from two 74LS175 four-bit latches
at K13 and L13, which have both inverting and non-inverting outputs.  The
non-inverting outputs go to the UC 2513 ROM (L15), while inverting outputs
go to the LC ROM (L14).

>From the schematic, the only TTL chip that appears to be needed solely for
the LC option is the 74LS157 at K12, but I'm not sure whether a UC-only
model would work without that installed. The manual doesn't show that part
as optional. My UC-only ADM3A does have it.

Upgrading from UC to UC/LC does require adding the H11 and J11 RAM chips
for the seventh bit of the refresh memory. Only one of the RAMs has to be
installed for a 12-row-ony model.

Re: Altair 8800 name Was: Re: Altair 680 Expansion Boards?

[Eric Smith]

On Thu, Dec 22, 2016 at 7:01 PM, drlegendre .  wrote:

> The Z80 also showed up in the Osborne, Kaypro and TRS-80 models.. mostly
> due to the fact that CP/M was written to it.
>

Use of the Z80 in the mainstream TRS-80 models (1 and III) had little or
nothing to do with CP/M.  The special CP/M with a non-standard TPA needed
for the Model 1 and III was just about useless, since it would only run
special TRS-80 versions of CP/M software. There were third-party mods for
the Model 1 and III to run a normal CP/M, but only a tiny fraction of
TRS-80 users did that.

CP/M may have been more of a factor for the Model II/12/16/6000, which
could run a normal CP/M without any hardware mods, as could the later Model
4 and 4P.  Most Model II family machines I saw in the wild were used to run
Radio Shack's accounting and business software on TRS-DOS II; few used
CP/M, possibly because there were much lower cost CP/M systems available
elsewhere.  Most Model 4 owners I knew didn't do any serious CP/M use on
it, and mostly used the 4 as an improved-spec III running TRS-DOS/LDOS/etc.

Re: Altair 8800 name Was: Re: Altair 680 Expansion Boards?

[drlegendre .]

"The Z80 had more players and more names than all the rest"

And yet it was essentially a bit-player in the days of the 'home computer'
revolution - at least in the US. CBM, Apple, Atari - the three big names in
home computers, all went with the 6502 family. And perhaps even more
importantly, so did Nintendo, in the NES. The main use of Z80 in US home
computing was in the absurdly small Timex / Sinclair ZX80 series - with
their awful cramped membrane keyboards and seriously limited sound & video.

The Z80 also showed up in the Osborne, Kaypro and TRS-80 models.. mostly
due to the fact that CP/M was written to it. Commodore also put one in the
C128, but by then, it was almost a dead letter.

On Thu, Dec 22, 2016 at 9:49 AM, allison  wrote:

> On 12/21/2016 07:06 PM, Sam O'nella wrote:
> > On Wed, Dec 21, 2016 at 5:54 PM, j...@cimmeri.com  wrote:
> >
> >>
> >> On 12/17/2016 1:23 PM, Stephen Pereira wrote:
> >>
> >>> I was (finally) lucky enough to acquire an Altair 680 back in
> November...
> >>>
> >> Is there any logic to the naming of these Altairs?   Wonder why it
> wasn't
> >> "Altair 8080" and "Altair 6800".   8800 and 680 don't follow the same
> >> pattern.
> >>
> >> --
> >>
> >> Had MITS made other Altairs...
> >>
> >> Altair 8800 = 8080
> >>8850 = 8085
> >>8860 = 8086
> >>8880 = 8088
> >>8286 = 80286
> >>8386 = 80386
> >>680  = 6800
> >>680  = 6809
> >>680  = 68000
> >>
> >> ;-),
> >>
> >> - JS
> >> 
> >>
> > lol, I would love to hear that too if anyone knows any stories behind the
> > naming. Used to hurt my head to remember that it was an 8800 not an 8080.
> > I know the fairly well published story about the name Altair but
> companies
> > and their model numbers are always odd.
> >
> My bets..
>
> I'd put $.09 on got the numbers wrong and went with it.
> then $0.01 on, it wasn't marketing.
> and $0.90 on, who cares.
>
> The 680 was from a market perspective a fail.  The successful 6800 was
> SWTP.
> The 6502 was dominated by Apple.
> The Z80 had more players and more names than all the rest.
>
> That of course is MY US centric view other countries had theirs too.
>
> Almost  all of the system naming of the day for the intel based systems
> and heirs
> (8080/8085/Z80/8088/8086) was irrational, illogical, and often just
> plain bad.
>
>
> Allison
>
>

General public machines (Was: Altair 8800 name Was: Re: Altair 680 Expansion Boards?

[Fred Cisin]

We all hang out with people who are smart enough to see things the same 
way that we do.  Accordingly, our choices in computers, cars, cellphone 
providers always look to us like the MAJORITY.   They are the BEST, and 
certainly the MOST POPULAR [among everybody that WE hang out with], but 
not necessarily the best selling.


If the world were just, and the BEST outsold the worst, then we would all 
be using Amiga :-)



On Thu, 22 Dec 2016, drlegendre . wrote:

"The Z80 had more players and more names than all the rest"
And yet it was essentially a bit-player in the days of the 'home computer'
revolution - at least in the US. CBM, Apple, Atari - the three big names in
home computers, all went with the 6502 family. And perhaps even more
importantly, so did Nintendo, in the NES.


And yet, somehow, z80 was outselling 6502!

http://jeremyreimer.com/m-item.lsp?i=137

Radio Shack, TRS-80, WAS one of the "three big names".  It had a 
not-insignificant share of the market, and until 1982 was the best 
selling.  Don't ignore the impact of having incompetents peddling in 
thousands of store, in every city and town!

Atari took a while longer to get market share.
http://www.trs-80.org/was-the-trs-80-once-the-top-selling-computer/

At the same time.
Depending on how you define "first" ("first" to show V "first" to ship V 
"first" to be available for shelf purchase) will define whether Apple, 
Commodore, or Radio Shack was "the first".  It is trivially esay to select 
a definition of "first" to make it your choice of those.   Apple was 
the first of those announced and shown.
I bought a TRS-80 ($400 (or $600 if you wanted their composite monitor 
and cassette player)) because it was the first one [by multiple months] 
that I could walk in the door of a local store and buy one.  The more 
appealing Apple, which had been announced earlier that TRS-80, was hard to 
come by for several more months.


That time differential of months seems inconsequential 40 years later, but 
it mattered to me right then.  And, for most rational measures, Apple, 
TRS-80 and Commodore initial releases were a tie.

(Was the photo finish by a nose, a whisker, or a hoof?)
When the 5150 came out in August 1981, it was months before I could 
actually get one.


AFTER the 5150 came out, people relized that TRS-80 was doomed, and in 
1982, Apple 2 finally started to outsell TRS-80.  It was LESS obvious that 
Apple 2 was doomed.  But, within Apple, they knew there were troubled 
times ahead, and came out with the disastrous Apple 3, and disastrous 
[from point of view of SALES] Lisa.


'Course IBM poisoned the market for everything else, and nothing else sold 
like IBM.   On August 12, 1981, I said "In 10 years, 3/4 of the market 
will be IBM PC and imitations of it."

It is amazingly impressive that Apple (Mac) survived IBM!
(If you think that Mac outsold PC, then you are looking at YOUR circle, 
and need to look at actual sales numbers)
But, by the time that the Mac came out, TRS-80 was finally becoming that 
"bit player" that some assume that it was, or should have been.



The main use of Z80 in US home
computing was in the absurdly small Timex / Sinclair ZX80 series - with
their awful cramped membrane keyboards and seriously limited sound & video.
Which was years later, and WAS a bit player and absurdly small. It was 
NEVER the main use of Z80 in USA home computing.  TRS-80 outsold them 
more than 100 to 1.
Was that really a membrane keyboard, or was it just a PICTURE of a 
keyboard as a recommendation, like the "part of this complete breakfast".



The Z80 also showed up in the Osborne, Kaypro and TRS-80 models.. mostly
due to the fact that CP/M was written to it. Commodore also put one in the
C128, but by then, it was almost a dead letter.


CP/M was written to 8080.  Z80 was simply the "hottest" 8080 compatible 
processor available.
Osborne and Kaypro were literally years later, and they did, indeed simply 
build clever, innovative CP/M machines.


I've never been sure how much market share CP/M had, since that was a 
different circle than I was hanging out in.  I'm sure that WITHIN that 
circle, it would seem like it was MOST of the market.


Commodore's Z80 in the 128 was due to unnecessary fear that they might 
lose market share to CP/M, when IBM should have been their big worry.
I don't know all of the details of the ST/Amiga technology swap, but BOTH 
were too late, if the primary goal was competing with IBM.


What percentage of Apple 2's had Z80 cards added to them?
(once estimated at an unbelievable 20%, and reputed to be why IBM thought 
that CP/M was a Microsoft product!)



--
Grumpy Ol' Fred ci...@xenosoft.com

Re: PDP-6s at MIT

[Noel Chiappa]

> From: Adrian Graham

> I was born 10 years too late to see it all as it grew. ... these early
> years are fascinating to me.

Well, you _can_ still experience ITS! It runs under a number of PDP-10
simulators (and there used to be an 'open-access' ITS system on the 'net at
its.svensson.org, but alas it doesn't seem to be up any more - although in a
fit of fore-sightedness, I downloaded the source to the HTTP server he wrote
while it was still up).

But you can still download one of the emulators that supports the special ITS
instructions on the PDP-10, KLH's KLH10, and SIMH; instructions, files, etc
here for KLH10:

  http://klh10.trailing-edge.com/

and SIMH:

  https://www.cosmic.com/u/mirian/its/

which give step-by-stop on how to get ITS running.

Noel

Re: PDP-6s at MIT

[Adrian Graham]

On 23/12/2016 00:00, "Noel Chiappa"  wrote:

>> From: Johnny Eriksson
> 
>> From the KI10 and onwards it includes PXCT, since these have the
>> concept of a previous context...
>> Given a pager for the KA10 PXCT would make sense there.
> 
> It turns out the KA ITS machines have an instruction that does roughly the
> same thing, but it's different. Here's the relevant code fragment from
> SYSTEM;ITS >:
> 
>   IFN KA10P,[
> 
>   SUBTTL STUFF PECULIAR TO KA-10 PROCESSOR



I love stuff like this and I'm quite miffed that I was born 10 years too
late to see it all as it grew. Of course I'm grateful for what I HAVE seen
over time, but these early years are fascinating to me.

-- 
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?

Re: PDP-6s at MIT

[Noel Chiappa]

> From: Johnny Eriksson

> From the KI10 and onwards it includes PXCT, since these have the
> concept of a previous context...
> Given a pager for the KA10 PXCT would make sense there.

It turns out the KA ITS machines have an instruction that does roughly the
same thing, but it's different. Here's the relevant code fragment from
SYSTEM;ITS >:

  IFN KA10P,[

  SUBTTL STUFF PECULIAR TO KA-10 PROCESSOR

  ;;;PAGING BOX INSTRUCTIONS

  LPM=102000,,  ;LOAD PG MEM STATE VECTOR DONT CLR ASSOC MEM
  LPMR= LPM 2,  ;CLEAR ASSOC MEM AND LOAD
  SPM= LPM 1,   ;STORE PG MEM STATE VECTOR
  LPMRI=LPM 6,  ;LOAD PM, CLEAR ASSOC REG, AND CAUSE INTERRUPT
  EXPGNG==4 .SEE UPQUAN ;4 TO TURN ON EXEC PAGING
  XCTR=103000,, ;EXECUTE INSTRUCTION WITH MAPPING CONTROLLED BY AC FIELD
;VIOLATION CAUSES USER MEM PROTECT INTERRUPT UNLESS INHIBITED
;VIOLATION ALSO SKIPS BUT THIS IS OF NO CONSEQUENCE UNLESS
;INTERRUPT IS INHIBITED SINCE PC WILL BE RESET FROM OPC
  XCTRI= XCTR 4,;XCTR WITH PAGE FAULT INHIBITED (SKIPS ON FAULT)
; AC FIELD VALUES FOR XCTR AND XCTRI
XR==1   ;MAP READ MAIN OPERAND OF SIMPLE INSTRUCTION (MOVE, 
SKIPL, HLL)
XW==2   ;MAP WRITE MAIN OPERAND OF SIMPLE INSTRUCTION (MOVEM)
XRW==3  ;MAP READ/WRITE OPERAND OF SIMPLE INSTRUCTION (E.G. 
IORM)
XBYTE==3;MAP BYTE DATA AND BYTE POINTER (ILDB, IDPB)
XBR==1  ;MAP BLT READ
XBW==2  ;MAP BLT WRITE
XBRW==3 ;MAP BOTH OPERANDS OF BLT
;KA10 PAGING BOX GOES BY WHETHER IT'S A READ OR WRITE (OR RW) 
CYCLE
;KL10 PAGING BOX WORKS DIFFERENTLY (SEE BELOW)
;DO NOT USE MULTI-OPERAND INSTRUCTIONS (DMOVE, PUSH, ETC.) WITH 
XCTR

The KL and KS are both different (although both use XCTR and XCTRI); the KL
stuff is later down in that file; the special KS instructions are in
KSHACK;KSDEFS > if anyone wants to look at them.

Noel

Re: PDP-6s at MIT

[Johnny Eriksson]

> Did the original KA10 have XCT too?

XCT is present in all PDP-10 processors.  From the KI10 and onwards it
includes PXCT, since these have the concept of a previous context...

Given a pager for the KA10 PXCT would make sense there.

>  Noel

--Johnny

Re: PDP-6s at MIT

[Noel Chiappa]

> AI memo 238: ITS Status Report, April 1972:
>> Actually the Project MAC Dynamic Modelling Group uses a non-paged
>> early offshoot of ITS on their PDP-10.

> So it seems DM kept using the non-paged version of ITS, probably like
> what their PDP-6 did.

No, their KA10 had a paging box, made by System Concepts - probably
programmatically similar to the ones on the other two KA's (looking at the ITS
source would probably verify that).

Note that in addition to the paging box, there were moderately extensive mods
to the KA10 itself (on all three machines) to add a variety of instructions
(to do things like, IIRC, flush the paging entry cache). Did the original KA10
have XCT too? And then there were things like the MAR.

Now, how soon after their KA10 arrived it had the paging box, etc, added I
have no idea - it sounds like they ran it without paging for a while.

 Noel

Re: PDP-6s at MIT

[Lars Brinkhoff]

AI memo 161A: ITS 1.5 Reference Manual, July 1969:
> An .OPEN on device USR with a second file name of "PDP10" may be made,
> in all the modes allowed for regular procedures, to access the memory
> of the PDP-10.

So at this time, the AI PDP-6 was still the primary CPU.

AI memo 238: ITS Status Report, April 1972:
> Actually the Project MAC Dynamic Modelling Group uses a non-paged
> early offshoot of ITS on their PDP-10.

So it seems DM kept using the non-paged version of ITS, probably like
what their PDP-6 did.

Re: Altair 8800 name Was: Re: Altair 680 Expansion Boards?

[allison]

On 12/21/2016 07:06 PM, Sam O'nella wrote:
> On Wed, Dec 21, 2016 at 5:54 PM, j...@cimmeri.com  wrote:
>
>>
>> On 12/17/2016 1:23 PM, Stephen Pereira wrote:
>>
>>> I was (finally) lucky enough to acquire an Altair 680 back in November...
>>>
>> Is there any logic to the naming of these Altairs?   Wonder why it wasn't
>> "Altair 8080" and "Altair 6800".   8800 and 680 don't follow the same
>> pattern.
>>
>> --
>>
>> Had MITS made other Altairs...
>>
>> Altair 8800 = 8080
>>8850 = 8085
>>8860 = 8086
>>8880 = 8088
>>8286 = 80286
>>8386 = 80386
>>680  = 6800
>>680  = 6809
>>680  = 68000
>>
>> ;-),
>>
>> - JS
>> 
>>
> lol, I would love to hear that too if anyone knows any stories behind the
> naming. Used to hurt my head to remember that it was an 8800 not an 8080.
> I know the fairly well published story about the name Altair but companies
> and their model numbers are always odd.
>
My bets..

I'd put $.09 on got the numbers wrong and went with it.
then $0.01 on, it wasn't marketing. 
and $0.90 on, who cares.

The 680 was from a market perspective a fail.  The successful 6800 was SWTP.
The 6502 was dominated by Apple.
The Z80 had more players and more names than all the rest.

That of course is MY US centric view other countries had theirs too.

Almost  all of the system naming of the day for the intel based systems
and heirs
(8080/8085/Z80/8088/8086) was irrational, illogical, and often just
plain bad.


Allison

Re: Mystery 8085-related IC identification needed please

[Adrian Graham]

On 21/12/2016 19:37, "Brent Hilpert"  wrote:

> On 2016-Dec-17, at 10:34 AM, Adrian Graham wrote:
>> One problem I have is that I've already found a few chips with dead outputs
>> so I've no idea if these will be any different. The pinouts I have match the
>> LS92 since pins 2/3/4/13 are NC. All testing so far has been done with a DMM
>> and cheap logic analyser. Since one of the possibly-LS92s is out of circuit
>> I'll build a little test circuit to see if it does actually count given a
>> clock source...
> 
> The counters may be the beginning of a video timing divider chain or a clock
> divider for the LUCY chip.
> (e.g. a diagram in the document you mentioned shows a div-6 between a 6MHz
> crystal osc and the LUCY chip.
> The division factor may vary of course in the executel depending on the
> crystal.)

That's a good point so I've revisited that section of board - one of the
things that started me down this whole path was a missing video sync before
I realised that the CPU wasn't running because of RESET and have spent many
days since tracing and measuring trying to find the source. I'm pretty sure
the LUCY chip is only there as a modem since the teletext display side of
things is handled by a Plessey MR9735 and a pair of 2114 RAM chips as page
store.

The board's also fairly logically laid out, split 50/50 between phone and
teletext with the teletext side split between CPU/glue, ROMs, RAM and
display logic. LUCY is well over to the left on the phone side.

> Also to keep in mind as you trace it out, 749x counters were often used with
> gates between the outputs and reset inputs to change the count modulus /
> division factor.

Hopefully there's nothing complex here, the reset inputs are inverted via a
74LS14, input to that is from the CMOS MC14081B mentioned elsewhere through
two hops over pins 1-2 then 3-4 of a 74LS04N.

> 
> 
> On 2016-Dec-17, at 10:34 AM, Adrian Graham wrote:
>> It's a 5-band red-red-black-black-violet so either 220R or 70k? Based on
>> what Pete said about the Z80 I'm going for 220R without pulling it out of
>> circuit.
> 
> 
> Looking at the photo in your earlier message
> http://www.binarydinosaurs.co.uk/stcexecuteltimingcircuits.jpg
> the wide red band on the resistors would be a 2% tolerance indicator.
> 
> As with Dwight's suggestion about colour confusion, if the resistors in
> question are those to the left of the two unmarked chips (or similar), they
> look like brown-black-black-red-wideRed, which would be standard 10K / 2%.

Those are pullups on an output from one of the '92s over to one of the 3
light green telephony bits that I've not looked up, marked 'NMC1515/6/7'

> You can try measuring resistors in circuits like this with a DMM.
> Switch the DMM leads to get both polarities through the resistor.
> It's not guaranteed as it depends on the connected circuitry and the R value,
> but one of the readings will often be your R value, or may confirm or give
> direction as to the value.

I normally pull up one end and test out of circuit but I'll give that a go
too.

Cheers!

-- 
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?

Re: Motorola MC14081B

[Adrian Graham]

On 21/12/2016 03:23, "allison"  wrote:

>> If one of the other outputs is driving a CMOS device the output may
>> not go high enough to satisfy it, however I would expect the reset
>> input on the 8085A to be TTL compatible.
> The 8085 reset input is not TTL, its schmidt trigger, and the level is
> at the upper level for TTL.
> If you use a 1K pullup then TTL, or open collector parts can be used as
> well as CMOS.

That explains the pullups I've seen on other 8085 devices I've found in
boxes recently like the Open University HEKTOR 8085 trainer.

> The 8085 was designed to have simple reset for cost sensitive aps where
> the circuit was usually
> 22K pullup and 1uf to ground.
> 
> If you using anything a 74HCxx would easily satisfy the drive and loading.

I think I've got a couple of 74HC08s that would do nicely, cheers!

-- 
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?

Re: Motorola MC14081B

[Adrian Graham]

On 21/12/2016 00:58, "Paul Berger"  wrote:

> On 2016-12-20 8:50 PM, Adrian Graham wrote:
>> Evening folks,
>> 
>> (it's evening here)
>> 
>> Typically for troubleshooting around $FESTIVAL I find a more-than-likely
>> dead MC14081B (CMOS quad dual-input AND gates) just as UK postage ends for
>> the next few days so getting a replacement won't happen until next week.
>> 
>> Question is, aside from having to make up an adapter board to change the
>> pins around and making sure Vcc is +5V is there any reason I can't use
>> something like a 74LS08 for testing? One of the outputs is RESET for an
>> 8085A so nothing too demanding.
> If one of the other outputs is driving a CMOS device the output may not
> go high enough to satisfy it, however I would expect the reset input on
> the 8085A to be TTL compatible.

Out of 4 outputs 2 are fed back into itself as inputs, one goes off to RESET
via a 74LS04N and the 4th disappears into the phone side of things possibly
to an Intel D8741A as well as seemingly being used as a base driver for a
BC548 transistor. Inputs are from a 5V-fed resistor network and Vcc for all
3 CMOS chips comes from a 12V line via a 1kohm resistor.

Tonight I'll make sure all the verdegris'd resistors and caps are ok.
 
The 8085's arrived yesterday too, thanks!

-- 
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?

Re: Late 90s Macintosh systems available to So Cal

[ben]

On 12/22/2016 2:10 AM, Steven Stengel wrote:

There's maybe hundreds of floppys and CDs - all included at one low low price. 
$0.00

Wow ... K-tell records to K-tell software.
Ben.

RE: ADM-3A Lower case ROM issue

[Steve Hatle]

 Original Message 
Subject: Re: ADM-3A Lower case ROM issue
From: "Ian S. King" 
Date: Wed, December 14, 2016 1:30 am
To: "General Discussion: On-Topic and Off-Topic Posts"


Take a look at the silk screen on the board - ISTR there's another chip
that needs to be added, some simple TTL logic. I converted mine several
years ago without problems - but that was with the original ROM.

-- 
Ian S. King, MSIS, MSCS, Ph.D. Candidate

--

Just as a follow-up - I got the two RAM ICs that were missing (2102 1K
RAM), and installed those along with the lower-case ROM, and everything
now works great.

Thanks everyone for your expertise and tips!

Steve

Re: Wanted Dead or Alive: Tadpole N40

[Ian Finder]

Forgot to add, in addition to purchasing at what price you name, I will
throw in a fully functional RDI PowerLite 1024x768 Sun4M laptop with two
internal 2.5" hard drives. Your N40 doesn't even have to work.

On Thu, Dec 22, 2016 at 2:04 AM, Ian Finder  wrote:

> Been having a bd month for hardware longevity. Lots of systems have
> died in 2016... A miserable year.
>
> Just took my only two Tadpole N40s out of cold storage and both are having
> some serious issues, stopping at 260 post code, no video, no status LCD,
> etc.
>
> If I had one more system, I'm sure I could get one running.
>
> If you have an N40 for sale, or that you'd consider selling, please ping
> me. I'd love to pay you for it :)
>
> Thanks,
>
> - Ian
>
> --
>Ian Finder
>(206) 395-MIPS
>ian.fin...@gmail.com
>



-- 
   Ian Finder
   (206) 395-MIPS
   ian.fin...@gmail.com

Wanted Dead or Alive: Tadpole N40

[Ian Finder]

Been having a bd month for hardware longevity. Lots of systems have
died in 2016... A miserable year.

Just took my only two Tadpole N40s out of cold storage and both are having
some serious issues, stopping at 260 post code, no video, no status LCD,
etc.

If I had one more system, I'm sure I could get one running.

If you have an N40 for sale, or that you'd consider selling, please ping
me. I'd love to pay you for it :)

Thanks,

- Ian

-- 
   Ian Finder
   (206) 395-MIPS
   ian.fin...@gmail.com

Re: Late 90s Macintosh systems available to So Cal

[Steven Stengel]

There's maybe hundreds of floppys and CDs - all included at one low low price. 
$0.00




> On Dec 21, 2016, at 5:07 PM, Brendan Shanks  wrote:
> 
> Hi, I’m local (work in Irvine near the split). I’d be interested in the 
> PowerBooks, and maybe some software. What kind of software do you have?
> 
> Brendan
> 
> 
>> On Dec 19, 2016, at 4:01 PM, Steven Stengel  wrote:
>> 
>> I have a small pile of late 90s Macintosh systems available for someone to 
>> pick-up in 92656. 
>> 
>> Performa 6400/100 tower
>> 
>> Some PowerBooks - 3400, 5300, 7630 
>> 
>> Also boxes of cables and software. 
>> 
>> LaserWriter 4/600P
>> 
>> Makes a great Christmas present!
>> 
>> Thanks-
>> Steve. 
>