Re: early (pre-1971) edge-triggered D flip-flop ICs

[Ethan Dicks via cctalk]

On Wed, Jul 19, 2017 at 6:10 PM, Eric Smith via cctalk
 wrote:
> I'm interested in the history of the logic design for the edge-triggered D
> flip-flop, as used in the SN7474...
>
> Does anyone know what year the SN7474 was introduced, or have an early
> datasheet for it (prior to the 1973 TTL Data Book For Design Engineers 1st
> Edition?

I have no datasheet, but I have examples on DEC M-series FLIP-CHIP
modules from my PDP-8/L, c. 1968.

I am pretty sure I have examples with 1968 date codes and possibly
1967 date codes.  I do find that when repairing DEC equipment of this
vintage, the two most common parts to fail are the 7474s and the
7440s.  Others have also written up their repair experiences and these
two parts top the list for common failures.

-ethan

Re: HP 300-series boot rom archive?

[Josh Dersch via cctalk]

On 7/19/2017 10:43 AM, Peter Brown via cctalk wrote:

If yours is dead, a bad power supply is the most likely issue.  The same
power supply was used in the 9000/340 but the 340's service manual doesn’t
tell you much about the internals of the supply.  The 345 service manual
tells you more but the supply for that box is a different model.

I  had a 9000/375 that would not start a couple of years ago - I think that 
there was a coin cell on the motherboard - once this was replaced, the machine 
booted fine.

Peter


Thanks, I gave that a shot.  Unfortunately, it didn't help.  But thanks 
for the suggestion!


- Josh

Re: early (pre-1971) edge-triggered D flip-flop ICs

[Eric Smith via cctalk]

Thanks for all the info, Brent!

The MECL II MC1022 is an edge-triggered D flip-flop using master-slave
design.  I'll have to look up the others you mentioned, especially the
National DM8510 and Sprague NE8828.

I've previously overlooked the MC778 mW RTL D flip-flop, which also uses a
variant of the three-SR design. However, it is a cruder device than the
MC3060 and SN7474, in that its asynchronous preset and clear only work when
the clock input is high, whereas they work at any time in the MC3060 and
SN7474. I haven't analyzed the circuit, but I'm guessing that they simply
didn't gate the preset and clear inputs into the master flip-flop of the
MC778, but only into the slave FF.

Best regards,
Eric

Re: Removing Pitting and Rust From an Enclosure

[Chuck Guzis via cctalk]

On 07/19/2017 07:13 PM, Fred Cisin via cctalk wrote:

> In most places other than the south and Chicago, Coke and Pepsi are what
> is used.   I don't think that SNL (Saturday Night Live) ever did a "No
> Coke; RC" skit.

There's also some stuff called "Naval Jelly"

http://www.loctiteproducts.com/p/s_trmt_naval/overview/Loctite-Naval-Jelly-Rust-Dissolver.htm

I was going to suggest leveling with Bondo, but that seemed the cheap
way to go.

I've used Bondo many times to fill missing bits of broken plastic
faceplates.   A little sanding and a coat of paint and it looks
downright presentable.

Machine tools (particularly Chinese ones) that use gray iron castings
are often smoothed with a Bondo-like putty before being painted.
(They're not very pretty under the putty).

If you were really serious about this, you could plate a generous coat
of copper, sand it smooth, then plate a layer of nickel.   But if you've
never done electroplating, it's probably not a good idea to start with
something valuable.

--Chuck

Re: Removing Pitting and Rust From an Enclosure

[Fred Cisin via cctalk]

On Wed, 19 Jul 2017, drlegendre . via cctalk wrote:

Chuck is right, but pits can also be filled.. JB Weld is one suggestion. It
can be sanded perfectly smooth & painted over. You can also try using some
auto-body spot filler, though I don't know how tough that is.


tough enough that it is sometimes used for auto-body spot filler!
Bondo is durable.
Fenders lead a rough life.

But, the purists insist that all auto-body spot filler should be done 
with lead.  Very similar to the way that some of us insist that any 
replacement parts of a classic somputer should be exactly the same as the 
original, perhaps down to with period appropriate date codes.


Painted over?
On something that was originally bare anodized or galvanized?
I like the "crackle-coat" paint,
but you could paint it pink and purple, like a "repurposed art" 026.



If the rust pits are deep, you can use muriatic acid to clean the rust out
of the pitting before you fill & coat. Make sure to follow-up any muriatic
use with some phosphoric acid.. else it's going to flash-rust like mad. If
you don't have a bottle of it, RC Cola is a cheap & available source of
phosphoric.. yes, it's low concentration, but it's enough to do the job.


In most places other than the south and Chicago, Coke and Pepsi are what 
is used.   I don't think that SNL (Saturday Night Live) ever did a "No 
Coke; RC" skit.

Re: Removing Pitting and Rust From an Enclosure

[drlegendre . via cctalk]

Chuck is right, but pits can also be filled.. JB Weld is one suggestion. It
can be sanded perfectly smooth & painted over. You can also try using some
auto-body spot filler, though I don't know how tough that is.

If the rust pits are deep, you can use muriatic acid to clean the rust out
of the pitting before you fill & coat. Make sure to follow-up any muriatic
use with some phosphoric acid.. else it's going to flash-rust like mad. If
you don't have a bottle of it, RC Cola is a cheap & available source of
phosphoric.. yes, it's low concentration, but it's enough to do the job.

On Wed, Jul 19, 2017 at 5:53 PM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> On 07/19/2017 03:13 PM, Fred Cisin via cctalk wrote:
>
> > To get rid of the pitting, you would have to grind, brush, or mill
> > down to below the depths of the pits. Or fill them in (bondo?) and
> > paint over. Maybe paint it like an 026 punch?
>
> Crackle-coat paint looks very nice.
>
> Removing pits by sanding is laborious and probably not worth the effort.
>
> --Chuck
>
>
>
>

Re: early (pre-1971) edge-triggered D flip-flop ICs

[Al Kossow via cctalk]

On 7/19/17 5:36 PM, Brent Hilpert via cctalk wrote:

> I also have the 65 TI catalog, which introduces the 5400 / future-7400 
> series, but the family is only half-a-dozen packages of gates and the 5470 FF 
> at that point.
> 

I started scanning Allied Electronics catalogs since they give prices and show 
product lines for early ICs
I'll do a few more, but I lost interest once I came across 
http://www.alliedcatalogs.com/
Don't like the Javascript mung wrapped around it though.

Re: early (pre-1971) edge-triggered D flip-flop ICs

[Al Kossow via cctalk]

On 7/19/17 4:40 PM, Brent Hilpert via cctalk wrote:

> There are near-type cross-refs in the 69 book to the National DM8510, Sprague 
> NE8828, Sprague USN7474, and Signetics N7474.
> 
> I can take and email you photos of the applicable pages if you like.
> Don't have a web site up right now to put them up on.
> 

They should all be on bitsavers. If not, i'll scan the backlog for stragglers

Eric's interest in the guts of the D flip-flop has been around for a while and
I've been watching for early references.

Re: early (pre-1971) edge-triggered D flip-flop ICs

[Brent Hilpert via cctalk]

On 2017-Jul-19, at 3:10 PM, Eric Smith via cctalk wrote:
> I'm interested in the history of the logic design for the edge-triggered D
> flip-flop, as used in the SN7474. The design is composed of three set-reset
> latches (six NAND gates total) per flip-flop.
> 
> Does anyone know what year the SN7474 was introduced, or have an early
> datasheet for it (prior to the 1973 TTL Data Book For Design Engineers 1st
> Edition?
> 
> The earliest datasheet I've found using this specific logic design for an
> edge-triggered D flip-flop is from a non-7400-series TTL chip, the Motorola
> MC3060/3160, which is a member of the MTTL III MC3000/MC3100 series.The
> MC3060 is covered in the Motorola 1968 IC databook, on page 4-138.
> 
> I've searched US patents for edge-triggered flip-flop design, but have not
> found one specifically for the three S-R latch design.
> 
> The subject came up as a result of a discussion on a private mailing list
> regarding the fact that the conventional J-K master-slave flip-flop design
> is NOT edge-triggered; pulses on J and/or K while the clock is high but
> stable can affect the Q (and not-Q) outputs of the FF at the following
> falling edge of the clock. That behavior is known as "pulse catching", and
> such a flip-flop is properly called pulse-triggered or level-triggered, but
> not edge-triggered.  Early datasheets on J-K master-slave flip-flops
> actually had correct terminology and specifically stated that J and K
> should not change while the clock is high.


The 1969 TI TTL IC Catalog presents slightly more info about the 7474, compared 
to the minimal table-oriented presentation of the 73 databook.
Extract;
Clock triggering occurs at a voltage level of the clock pulse 
and is not directly related to the transition time
of the positive going pulse. After the clock input threshold 
voltage has been passed, the data input (D) is locked out.

These dual flip-flops have the same clocking characteristics of 
the SN5470/SN7470 gated (edge-triggerred) flip-flop circuits, . . .

A transistor level schematic is present as well.

The internal operation of the 7474 is discussed in the Sams book "TTL" by 
George Flynn / 1974.
A decent page+ of text , but I haven't read it in depth so don't really know 
how good an explanation it is.
Cursorily, it seems to be just a logic explanation that anyone could figure out 
by working through the logic diagram,
not an electrical level explanation.

There are near-type cross-refs in the 69 book to the National DM8510, Sprague 
NE8828, Sprague USN7474, and Signetics N7474.

I can take and email you photos of the applicable pages if you like.
Don't have a web site up right now to put them up on.

Re: Removing Pitting and Rust From an Enclosure

[Chuck Guzis via cctalk]

On 07/19/2017 03:13 PM, Fred Cisin via cctalk wrote:

> To get rid of the pitting, you would have to grind, brush, or mill
> down to below the depths of the pits. Or fill them in (bondo?) and
> paint over. Maybe paint it like an 026 punch?

Crackle-coat paint looks very nice.

Removing pits by sanding is laborious and probably not worth the effort.

--Chuck

Re: early (pre-1971) edge-triggered D flip-flop ICs

[Chuck Guzis via cctalk]

On 07/19/2017 03:10 PM, Eric Smith via cctalk wrote:
> I'm interested in the history of the logic design for the edge-triggered D
> flip-flop, as used in the SN7474. The design is composed of three set-reset
> latches (six NAND gates total) per flip-flop.
> 
> Does anyone know what year the SN7474 was introduced, or have an early
> datasheet for it (prior to the 1973 TTL Data Book For Design Engineers 1st
> Edition?
> 
> The earliest datasheet I've found using this specific logic design for an
> edge-triggered D flip-flop is from a non-7400-series TTL chip, the Motorola
> MC3060/3160, which is a member of the MTTL III MC3000/MC3100 series.The
> MC3060 is covered in the Motorola 1968 IC databook, on page 4-138.

It's interesting.  I pulled out my Moto 1969 databook, and while the
7400 series numbers jump for 7473 to 7475, but MC7479 is listed as an
exact replacement for the TI 7474.

There are, of course, earlier edge-triggered flip-flops in other logic
families; e.g., the MC1022 ECL flop.

--Chuck

Re: Diskette size (was: Repurposed Art (ahem...)

[Anders Nelson via cctalk]

"That is why they switched from 8 foot to 5.25 foot floppies."

LOL

On Wed, Jul 19, 2017 at 12:15 PM Fred Cisin via cctalk <
cctalk@classiccmp.org> wrote:

> >> Did any one ever use keypunch to tape or 8' floppy?
> On Wed, 19 Jul 2017, Mike Stein via cctalk wrote:
> > Those 8' floppies were a PITA to handle and store, but
> > they sure held a lot of data...
> > ;-P
>
> That is why they switched from 8 foot to 5.25 foot floppies.
>
>
> Punchcard size is reputed to have been chosen for use of readily available
> currency bins (was the dollar bill reduced in size as a reflection of its
> declining value :-?
>
> 8 inch floppies (1971 23FD) were intended to be stored like 8.5x11 paper.
>
>
> I'd like to find more info about the decision of 5.25 inch.
>
> http://archive.computerhistory.org/resources/text/Oral_History/5.25_3.5_Floppy_Drive/5.25_and_3.5_Floppy_Panel.oral_history.2005.102657925.pdf
> is one of the only sources.
>
> In it,
> Don Massaro, of Shugart Associates, says that they chose 5.25" as the
> smallest that they could make a diskette that COULD NOT be put in a shirt
> pocket, deliberately avoiding that particular method of damaging a
> diskette.
>
> They all agree that Wang was the impetus.  That Steve Jobs was pestering
> them for a cheap drive, but due to the holes in his jeans and personal
> hygiene?, they never took him seriously.
>
> George Sollman said that the drive size was shosen to match tape drives.
>
> (also mentioned in a sidebar in Byte 35? years ago:)
> However Jimmy Adkisson of Shugart Associates claims that they were in a
> bar with Dr. Wang and his people, and when they asked Wang what size it
> should be, he picked up a bar napkin.  Adkisson took the napkin back to
> the office and measured it.   I want to find out what bar, and whether
> that bar has personalized napkins!
> (I'd also like to get novelty napkins printed up with a picture of a
> diskette and a copy of that story printed on the back!)
>
>
> Later, there was the "battle of the shirt-pocket disks" between 3"
> (Amstrad), 3.25" (Dysan) and 3.5" (Sony).  Dysan, who did not want to
> retool to make hard-shell 3" or 3.5", designed a 3.25" floppy floppy.
> They made the seemingly sensible assumption that the size conflict would
> be won by whichever had software available, and they bet the company on a
> 3.25" software publishing venture.  Almost all MAJOR programs were
> available on 3.25" diskettes, even though the Seequia Chameleon 325 was
> the only computer that ever made it to market with a 3.25" drive.
> 3.9", 2.9", 2.8", and several others, never caught on.
>
>
> HP and Apple went with Sony 3.5", and when IBM also went 3.5" (abandoning
> their announced 3.9"), that sealed it.
> The earliest 3.5" disks (I have a few "Shugart" ones) had no shutter.
> Then there was a sliding spring loaded shutter, with a place on the disk
> to labelled "PINCH" (with an arrow) to release the shutter.
> When full automatic shutters came out, the word "PINCH" was dropped, but
> the arrow was left on as a reminder of which direction the disk went into
> the drive, even though it only went in one way (unlike 8" and 5.25" disks
> that would fit into the drive 8 ways)
>
>
> It is also amusing about the distortions in memory perceptions.
> I have a [slightly crashed] RAMAC? 24" 100K? platter.  I would show it to
> my students.  Whenever it was mentioned later, the students would recall
> it as being "three or four feet diameter!"
>
> Similarly, we often waste time in futile attempts to track down "ten inch"
> and "twelve inch" floppy stories that were simply misremembrances of 8".
> (If you don't believe that, FIND ONE)
>
>
> http://www.ricomputermuseum.org/Home/shirt-pocket-diskette
> is an UNCREDITED direct copy of a post that I made in this group.
> Lack of attribution isn't very bad.   But adding "RICM notes that" on the
> beginning of one of my paragraphs turns that into theft.  (3 of less than
> 10 words changed)
> Is the rest of "their" content also similarly plagiarized?
> Are the pictures of THEIR collection, or unauthorized copies of other
> people's pictures?
>
> --
> Grumpy Ol' Fred ci...@xenosoft.com
>
-- 
--
Anders Nelson
+1 (517) 775-6129
www.erogear.com

RE: Removing Pitting and Rust From an Enclosure

[Fred Cisin via cctalk]

> You can't remove pitting. You mean remove the dark oxide?

On Wed, 19 Jul 2017, Rob Jarratt via cctalk wrote:

Well yes, I suppose so, and anything that can be done to make the result
look a bit better after removing the dark oxide.


maybe steel wool?
or try a wire brush that is softer than the material (such as brass)

To get rid of the pitting, you would have to grind, brush, or mill down to 
below the depths of the pits.

Or fill them in (bondo?) and paint over.
Maybe paint it like an 026 punch?

early (pre-1971) edge-triggered D flip-flop ICs

[Eric Smith via cctalk]

I'm interested in the history of the logic design for the edge-triggered D
flip-flop, as used in the SN7474. The design is composed of three set-reset
latches (six NAND gates total) per flip-flop.

Does anyone know what year the SN7474 was introduced, or have an early
datasheet for it (prior to the 1973 TTL Data Book For Design Engineers 1st
Edition?

The earliest datasheet I've found using this specific logic design for an
edge-triggered D flip-flop is from a non-7400-series TTL chip, the Motorola
MC3060/3160, which is a member of the MTTL III MC3000/MC3100 series.The
MC3060 is covered in the Motorola 1968 IC databook, on page 4-138.

I've searched US patents for edge-triggered flip-flop design, but have not
found one specifically for the three S-R latch design.

The subject came up as a result of a discussion on a private mailing list
regarding the fact that the conventional J-K master-slave flip-flop design
is NOT edge-triggered; pulses on J and/or K while the clock is high but
stable can affect the Q (and not-Q) outputs of the FF at the following
falling edge of the clock. That behavior is known as "pulse catching", and
such a flip-flop is properly called pulse-triggered or level-triggered, but
not edge-triggered.  Early datasheets on J-K master-slave flip-flops
actually had correct terminology and specifically stated that J and K
should not change while the clock is high.

RE: Removing Pitting and Rust From an Enclosure

[Rob Jarratt via cctalk]

Well yes, I suppose so, and anything that can be done to make the result
look a bit better after removing the dark oxide.

 

Regards

 

Rob

 

From: dwight [mailto:dkel...@hotmail.com] 
Sent: 19 July 2017 22:16
To: r...@jarratt.me.uk; Rob Jarratt ; General
Discussion: On-Topic and Off-Topic Posts 
Subject: Re: Removing Pitting and Rust From an Enclosure

 

You can't remove pitting. You mean remove the dark oxide?

Dwight

 

  _  

From: cctalk  > on behalf of Rob Jarratt via cctalk
 >
Sent: Wednesday, July 19, 2017 12:52:44 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Removing Pitting and Rust From an Enclosure 

 

The TURBOchannel extender I got has a bit of rust and quite a lot of dark
pitting on the steel surfaces. I am not sure what the finish is, whether it
is anodized or galvanized. In any case, does anyone have recommendations for
how to remove the unsightly pitting? Bear in mind that I am in the UK, so
brands available in the US may not be available here and it may be more
useful to know what the active ingredients are.

 

Also, the case has some very annoying metal "fins". They don't look original
to me, but can anyone tell me if they are? Here is a picture of the feet:
https://rjarratt.files.wordpress.com/2017/07/turbochannel-extender-base.jpg

 

Thanks

 

Rob

Re: Removing Pitting and Rust From an Enclosure

[dwight via cctalk]

You can't remove pitting. You mean remove the dark oxide?

Dwight



From: cctalk  on behalf of Rob Jarratt via 
cctalk 
Sent: Wednesday, July 19, 2017 12:52:44 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Removing Pitting and Rust From an Enclosure

The TURBOchannel extender I got has a bit of rust and quite a lot of dark
pitting on the steel surfaces. I am not sure what the finish is, whether it
is anodized or galvanized. In any case, does anyone have recommendations for
how to remove the unsightly pitting? Bear in mind that I am in the UK, so
brands available in the US may not be available here and it may be more
useful to know what the active ingredients are.



Also, the case has some very annoying metal "fins". They don't look original
to me, but can anyone tell me if they are? Here is a picture of the feet:
https://rjarratt.files.wordpress.com/2017/07/turbochannel-extender-base.jpg



Thanks



Rob

Speaking of detached keyboards

[Adam Thornton via cctalk]

Among the things I found when I was unpacking into my new house was a
keyboard (minus a couple arrow keys) from a Model 40 Teletype.  I
apparently paid $5 for it from the Island of Misfit Toys at the back of
Gateway Electronics in STL.

Anyway.  As keyboards go, it is super-duper clicky.

It has a 9-pin rectangular connector at the back.  Fritz Mueller pointed me
to the service manuals, but I was wondering, before I embark on any heroic
and stupid endeavorshas someone already built a
conversion-to-USB-or-PS2-or-AT keyboard kit for one?

Adam

Removing Pitting and Rust From an Enclosure

[Rob Jarratt via cctalk]

The TURBOchannel extender I got has a bit of rust and quite a lot of dark
pitting on the steel surfaces. I am not sure what the finish is, whether it
is anodized or galvanized. In any case, does anyone have recommendations for
how to remove the unsightly pitting? Bear in mind that I am in the UK, so
brands available in the US may not be available here and it may be more
useful to know what the active ingredients are.

 

Also, the case has some very annoying metal "fins". They don't look original
to me, but can anyone tell me if they are? Here is a picture of the feet:
https://rjarratt.files.wordpress.com/2017/07/turbochannel-extender-base.jpg

 

Thanks

 

Rob

Re: HP 300-series boot rom archive?

[Peter Brown via cctalk]

> If yours is dead, a bad power supply is the most likely issue.  The same
> power supply was used in the 9000/340 but the 340's service manual doesn’t
> tell you much about the internals of the supply.  The 345 service manual
> tells you more but the supply for that box is a different model.

I  had a 9000/375 that would not start a couple of years ago - I think that 
there was a coin cell on the motherboard - once this was replaced, the machine 
booted fine.

Peter



From: Josh Dersch 
Sent: 18 July 2017 03:42
To: Curator
Cc: General Discussion: On-Topic and Off-Topic Posts; Lee Courtney; Lee Courtney
Subject: Re: HP 300-series boot rom archive?

On Mon, Jul 17, 2017 at 8:13 PM, Curator  wrote:

> I have to agree with Lee's view on the HP300...  THIS is an HP300...
> http://www.hpmuseum.net/display_item.php?hw=116
HP Computer Museum
www.hpmuseum.net
Description: The HP 300 was an integrated multi-user computer that supported up 
to 16 attached terminals. The all-in-one box included processing hardware, a 12 
MB ...





Yep yep, I replied to Lee (thought I'd replied to the list, apparently I
don't know how that works anymore) and apologized for not being specific
enough :).


>
>
> Now for the HP9000/375 - I've not seen a service manual for the 375 but
> here's a link to the Service Handbook.
>
> http://www.hpmuseum.net/document.php?hwfile=2053
>
> There's a list of hardware related documents in that handbook but there's
> no mention of a Service Manual.  Perhaps it was an unlisted HP internal
> document - but the handbook looks like it has enough for the typical field
> repair efforts of its era..
>

Yep, I found that one, but it's not useful for actually repairing anything
beyond basic board-swapping.


>
> If yours is dead, a bad power supply is the most likely issue.  The same
> power supply was used in the 9000/340 but the 340's service manual doesn’t
> tell you much about the internals of the supply.  The 345 service manual
> tells you more but the supply for that box is a different model.
>

It's not the supply, I've tested the supply, and I've tested the board in
known-working chassis and it behaves identically (all diagnostic LEDs on, a
buzz coming from the speaker, similar to the short one you normally hear at
power-up, but forever.)  It seems like it's probably not coming out of
reset but that's just a guess.

Thanks!
Josh



>
> The supply was most likely sourced from a third party so you might have to
> hunt around for an OEM part number on the unit and maybe get lucky with
> schematics on the web.  Otherwise standard troubleshooting tasks for switch
> mode power supplies would apply..  http://www.repairfaq.org/sam/
> smpsfaq.htm#smpssctos
>
> David Collins
> HP Computer Museum
>
> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Lee
> Courtney via cctalk
> Sent: Monday, 17 July 2017 4:36 PM
> To: Josh Dersch ; General Discussion: On-Topic and
> Off-Topic Posts 
> Subject: Re: HP 300-series boot rom archive?
>
> Hi Josh,
>
> "lot of HP 300 gear"
>
> Being picky here, but I worked at HP in the HP 300 days and the system you
> acquired does not sound like an HP 300, aka Amigo (
> https://en.wikipedia.org/wiki/HP_300), but rather a model of HP 9000
> desktop machines (M68K based?).
>
> Lee C.
>
> On Sun, Jul 16, 2017 at 7:50 PM, Josh Dersch via cctalk <
> cctalk@classiccmp.org> wrote:
>
> > Hi all --
> >
> > I picked up a small lot of HP 300 gear yesterday and I'm working on
> > getting them going.  In particular, I have a 9000/350 that I'd like to
> > use but it has what appears to be a very early boot ROM (dated 7/9/87,
> > version
> > A2) and it doesn't recognize the 98658 SCSI controller I'd like to use
> > in it -- it enumerates as "127 at 14" rather than getting a the usual
> > identification.  I'm hoping that later revisions might support this card.
> > (I lack functioning HP-IB storage at the moment).  Is there an archive
> > of ROM images for the 300 series anywhere?  Anyone have a 350 with a
> > later boot ROM they can image for me?
> >
> > (Also, if anyone has a real service manual for the 9000/375, drop me a
> > line -- I have one that's stone dead...)
> >
> > Thanks as always,
> >
> > Josh
> >
> >
>
>
> --
> Lee Courtney
> +1-650-704-3934 cell
>
>

Re: PDP11 and Simh Floating point

[Chuck Guzis via cctalk]

On 07/19/2017 09:49 AM, Paul Koning via cctalk wrote:

> An example where you'd be way off is the CDC 6000 series, which has
> integer mantissas and doesn't necessarily normalize the answers.  So
> even apart from the encoding conversion, the answer won't match.  Or
> the Electrologica X8, which has an exponent range substantially
> larger than IEEE, uses integer mantissa, and has a normalization rule
> entirely different from IEEE.
...or the IBM S/360, with uses a strange floating point normalized to 4
bit boundaries and a biased exponent that's a power of 16, not 2. 1 bit
for sign, 7 bits for exponent (biased by 64) and 24 bits for mantissa.

Double-precision (64 bits) extended the mantissa to 56 bits; given the 4
bit normalization, not much more that CDC 6000 single-precision (48 bits).

--Chuck

Re: PDP11 and Simh Floating point

[Douglas Taylor via cctalk]

On 7/18/2017 11:38 AM, Paul Koning via cctalk wrote:

On Jul 18, 2017, at 11:04 AM, Douglas Taylor via cctalk  
wrote:

How does SIMH perform floating point operations for the PDP-11 simulation?

If I run a numerical computation on real PDP-11 hardware and also on Simh how 
do you talk about the comparison?

You can look for yourself: PDP11/pdp11_fp.c.  The code clearly implements the 
floating point operations the hard way: picking apart the pieces and 
manipulating them as needed.

For stuff like this, the devil is always in the details.  Some floating point 
implementations have odd corner cases that aren't necessarily well documented, 
if at all.  But it's clear the intent is that SIMH should produce the same 
answers as a real PDP-11.

An example of floating point emulation that would be wrong is to convert to IEEE and 
operate on "double" values, then convert back.  I've done that in the past as a 
first stab, but you can't do that if you want the emulation to be anywhere near accurate.

paul



Paul

The pdp11_fp.c code is quite intricate.  If simh was a simple simulation 
it would take the easy route and use the intel fp co-processor as you 
point out, but it doesn't.  It actually 'emulates' what the pdp11 would 
do in hardware.  Very interesting, that way you can get the exact same 
answers from the emulator that you would from the real hardware.


It would not be an interesting comparison if the two got slightly 
different numerical answers.


Thanks for pointing out the pdp11_fp.c code.

Doug

Re: iMac ethernet connection quit - help?

[Tapley, Mark via cctalk]

All,
update - sorry for long delay, life happens.

I did execute the firmware update procedure from the URL listed 
up-thread. It went seamlessly (I held the programmer’s button in with a deer 
antler from the greenbelt behind my house - is that a unique way to update an 
iMac?)
No change in the ethernet behavior. I did notice that when I command 
(via System Preferences -> Network (ethernet) -> advanced -> hardware (I think, 
not on the 10.4 machine right now) the rate to 100TX full-duplex, a) the 
“connect” light on the hub will turn on, and b) the “power/busy” light will go 
off for a while - presumably indicating full blast messages swamping the hub 
for a few minutes.
I looked at the Service manual .pdf for that model, and the battery 
holder is indeed close to the ethernet port (the whole I/O subpanel, in fact). 

Next stop, I’ll pull the cover off the machine and see whether I can 
spot any spilled battery electrolyte from the old battery or anything else 
suspicious looking on the logic board in that area, and will report what I find.

- Mark

Diskette size (was: Repurposed Art (ahem...)

[Fred Cisin via cctalk]

Did any one ever use keypunch to tape or 8' floppy?

On Wed, 19 Jul 2017, Mike Stein via cctalk wrote:

Those 8' floppies were a PITA to handle and store, but
they sure held a lot of data...
;-P


That is why they switched from 8 foot to 5.25 foot floppies.


Punchcard size is reputed to have been chosen for use of readily available 
currency bins (was the dollar bill reduced in size as a reflection of its 
declining value :-?


8 inch floppies (1971 23FD) were intended to be stored like 8.5x11 paper.


I'd like to find more info about the decision of 5.25 inch.
http://archive.computerhistory.org/resources/text/Oral_History/5.25_3.5_Floppy_Drive/5.25_and_3.5_Floppy_Panel.oral_history.2005.102657925.pdf
is one of the only sources.

In it,
Don Massaro, of Shugart Associates, says that they chose 5.25" as the 
smallest that they could make a diskette that COULD NOT be put in a shirt 
pocket, deliberately avoiding that particular method of damaging a 
diskette.


They all agree that Wang was the impetus.  That Steve Jobs was pestering 
them for a cheap drive, but due to the holes in his jeans and personal 
hygiene?, they never took him seriously.


George Sollman said that the drive size was shosen to match tape drives.

(also mentioned in a sidebar in Byte 35? years ago:)
However Jimmy Adkisson of Shugart Associates claims that they were in a 
bar with Dr. Wang and his people, and when they asked Wang what size it 
should be, he picked up a bar napkin.  Adkisson took the napkin back to 
the office and measured it.   I want to find out what bar, and whether 
that bar has personalized napkins!
(I'd also like to get novelty napkins printed up with a picture of a 
diskette and a copy of that story printed on the back!)



Later, there was the "battle of the shirt-pocket disks" between 3" 
(Amstrad), 3.25" (Dysan) and 3.5" (Sony).  Dysan, who did not want to 
retool to make hard-shell 3" or 3.5", designed a 3.25" floppy floppy. 
They made the seemingly sensible assumption that the size conflict would 
be won by whichever had software available, and they bet the company on a 
3.25" software publishing venture.  Almost all MAJOR programs were 
available on 3.25" diskettes, even though the Seequia Chameleon 325 was 
the only computer that ever made it to market with a 3.25" drive.

3.9", 2.9", 2.8", and several others, never caught on.


HP and Apple went with Sony 3.5", and when IBM also went 3.5" (abandoning 
their announced 3.9"), that sealed it.

The earliest 3.5" disks (I have a few "Shugart" ones) had no shutter.
Then there was a sliding spring loaded shutter, with a place on the disk 
to labelled "PINCH" (with an arrow) to release the shutter.
When full automatic shutters came out, the word "PINCH" was dropped, but 
the arrow was left on as a reminder of which direction the disk went into 
the drive, even though it only went in one way (unlike 8" and 5.25" disks 
that would fit into the drive 8 ways)



It is also amusing about the distortions in memory perceptions.
I have a [slightly crashed] RAMAC? 24" 100K? platter.  I would show it to 
my students.  Whenever it was mentioned later, the students would recall 
it as being "three or four feet diameter!"


Similarly, we often waste time in futile attempts to track down "ten inch" 
and "twelve inch" floppy stories that were simply misremembrances of 8".

(If you don't believe that, FIND ONE)


http://www.ricomputermuseum.org/Home/shirt-pocket-diskette
is an UNCREDITED direct copy of a post that I made in this group.
Lack of attribution isn't very bad.   But adding "RICM notes that" on the 
beginning of one of my paragraphs turns that into theft.  (3 of less than 
10 words changed)

Is the rest of "their" content also similarly plagiarized?
Are the pictures of THEIR collection, or unauthorized copies of other 
people's pictures?


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

Re: Diehl Combitron

[Rick Bensene via cctalk]

This is a truly wonderful accomplishment, as well as a great remembrance of a 
true genius in early electronic calculator design, not to mention computer 
design.  

Stan Frankel isn't all that well known, but those that do know of him hold him 
in high regard. He was a master of minimizing circuitry yet still providing 
great functionality. He deserves more of a place in history than he has 
received, but fortunately, more and more recognition of his accomplishments are 
being acknowledged by historians as time goes on.

I will pass this posting on to his son, Allan, with whom I communicate with 
frequently. I am sure he will love this remembrance of his father.

Rick Bensene
The Old Calculator Museum
http://oldcalculatormuseum.com


From: Christian Corti via cctalk 
Sent: Jul 19, 2017 4:20 AM
To: cctalk@classiccmp.org
Subject: Diehl Combitron

Hi,
I want to share the latest result of a bachelor thesis in our museum. We 
are now able to program and load arbitrary machine programs and run them 
on the Combitron. As a proof-of-concept, the student wrote an hommage to 
Stanley Frankel, the designer of the CPU, by writing a boot tape that in 
the end, fills the M delay line with data that is displayed on a scope, 
triggering to the beginning of a 110 bit word.

http://computermuseum.informatik.uni-stuttgart.de/pics/combitron/sf1.jpg
http://computermuseum.informatik.uni-stuttgart.de/pics/combitron/sf2.jpg

Christian

Re: Repurposed Art (ahem...)

[Mike Stein via cctalk]

- Original Message - 
From: "ben via cctalk" 
To: 
Sent: Tuesday, July 18, 2017 10:45 PM
Subject: Re: Repurposed Art (ahem...)


> On 7/18/2017 2:11 PM, Fred Cisin via cctalk wrote:
>> On Tue, 18 Jul 2017, Ed via cctalk wrote:
>>> at least they did not glue a bunch of  gears on it and call it steam
>>> punk...
>>> I have  run across  weird glued and punked items on  ebay...   what a 
>>> bunch
>>> of  AH's
>> 
>> a model 026 punch is already a masterpiece of steam punk.
>> 
>> A model 029, on the other hand, appeals to trekkies.
>> 
>> 
>> I think that a keypunch rationalized as art needs a clock on it:
>> http://www.ebay.com/itm/Melting-Clock-DT-/262670473087?hash=item3d2861577f:g:kE4AAOSwONBZFFUo
>>  
> 
> Yes, but the clock runs counter - clockwise.
> 
>> -- 
>> Grumpy Ol' Fred ci...@xenosoft.com
> 
> Did any one ever use keypunch to tape or 8' floppy?
> Ben.
---
Those 8' floppies were a PITA to handle and store, but
they sure held a lot of data...

;-P

RE: Repurposed Art (ahem...)

[Bill Gunshannon via cctalk]

From: cctalk [cctalk-boun...@classiccmp.org] on behalf of ben via cctalk 
[cctalk@classiccmp.org]
Sent: Tuesday, July 18, 2017 10:45 PM
To: cctalk@classiccmp.org
Subject: Re: Repurposed Art (ahem...)

On 7/18/2017 2:11 PM, Fred Cisin via cctalk wrote:
> On Tue, 18 Jul 2017, Ed via cctalk wrote:
>> at least they did not glue a bunch of  gears on it and call it steam
>> punk...
>> I have  run across  weird glued and punked items on  ebay...   what a
>> bunch
>> of  AH's
>
> a model 026 punch is already a masterpiece of steam punk.
>
> A model 029, on the other hand, appeals to trekkies.
>
>
> I think that a keypunch rationalized as art needs a clock on it:
> http://www.ebay.com/itm/Melting-Clock-DT-/262670473087?hash=item3d2861577f:g:kE4AAOSwONBZFFUo

Yes, but the clock runs counter - clockwise.

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

Did any one ever use keypunch to tape or 8' floppy?
Ben.


If you mean a commercial product in hardware, I doubt it. And, it wouldn't be 
"keypunch", now, would it?

I did, however, develop a system when I was at West Point (many, many years
ago) that did the equivalent.  I developed a system under UCSD-Pascal running on
Terak 8510 Micro Computers that allowed the offline input off data by the input
(same as keypunch) operators from the USMA Admissions Office. It all went to
8" disks and at the end of the day the shift supervisor used another program I
wrote to transfer it all to the Univac-1100 for overnight batch processing.  I 
even
got my picture in the Post Newspaper along with a story about "distributed data
processing" coming to USMA.

bill

Diehl Combitron

[Christian Corti via cctalk]

Hi,
I want to share the latest result of a bachelor thesis in our museum. We 
are now able to program and load arbitrary machine programs and run them 
on the Combitron. As a proof-of-concept, the student wrote an hommage to 
Stanley Frankel, the designer of the CPU, by writing a boot tape that in 
the end, fills the M delay line with data that is displayed on a scope, 
triggering to the beginning of a 110 bit word.


http://computermuseum.informatik.uni-stuttgart.de/pics/combitron/sf1.jpg
http://computermuseum.informatik.uni-stuttgart.de/pics/combitron/sf2.jpg

Christian

Re: Repurposed Art (ahem...)

[Philipp Hachtmann via cctalk]

On 18.07.2017 16:27, Cory Heisterkamp via cctalk wrote:

On Tue, Jul 18, 2017 at 9:14 AM, Philipp Hachtmann via cctalk <



 From a seller's point of view, they've got a keypunch that's worth less

painted than if it were original, unless you're an art fanatic with lots of
space to display such a thing. Me, I'd rather have a clean example to
demo/use. The time and cost to strip it to make it presentable just isn't
worth it, so at this point I'd wager the larger audience either wants it
for parts (in which case $599 is probably also too much) or to the keyboard
enthusiasts who probably gave a couple hundred for that KB. -C


If I got a painted machine like that - I'd never try to "restore" it to 
some grey/blue something. I'd consider the psychedelic dessin as 
original because it was still in use while looking that way. I am sure 
that there is an (unknown) story behind that. For me it would be very 
interesting to get to know this story...


What are keyboard collectors?!? That sounds really bad. Don't like the 
idea. And much steampunk is dangerous for collectibles and plain shit. 
Steampunk might only be justified if you really build really working 
weird machines and devices - not just mocking up something.
So if you come up with a blinking brass steam boat which features a 
mechanical computer as auto-pilot, I guess that will be fine.


:-)

Re: HP 300-series boot rom archive?

[r.stricklin via cctalk]

On Jul 18, 2017, at 8:38 AM, Al Kossow via cctech wrote:

> When MAME started supporting the 68K 9000s, I made an effort to go through 
> all of my machines
> and dump the firmware. I didn't have a 375, which is why it isn't there. It 
> would be nice if
> some other collectors (Bear?) would dump any firmware out of their machines. 

I don't have a 375, but I'll be glad to provide what I can. Having a sense of 
what, specifically, was being sought (and where to send it) would help me focus 
effort.

ok
bear.

-- 
until further notice

Re: Repurposed Art (ahem...)

[Ed via cctalk]

Pete - 
Sad about the  McGraw-Hill Electronics
Which issues are  you missing!?
Ed# _www.smecc.org_ (http://www.smecc.org)  
 
 
 
In a message dated 7/18/2017 9:43:25 P.M. US Mountain Standard Time,  
cctalk@classiccmp.org writes:

The  paint job doesn't bother me much. I had a working 26 that I donated to
CHM.  Its things like selling the keyboard then expecting to get more the
$20 for  the remains. My Teletype version of that is a Western Union 2-B in
good  shape missing all it key caps and motor. Both pulled to sell to the
'steam  punk' crowed.
BTW not putting them down at all. I've not met one who would  do something
like that, its the people who think they can make a sale that  do the 
damage.
Other examples of things I am collecting, McGraw-Hill  Electronics. Finding
a 2 foot stack of issues I don't have that have been  gutted for their
advertisements.
Atwater Kent that worked trashed for  the cabinet, and a crappy job at that.
Could go on for hours of  examples.


On Tue, Jul 18, 2017 at 1:11 PM, Fred Cisin via cctalk  <
cctalk@classiccmp.org> wrote:

> On Tue, 18 Jul 2017, Ed  via cctalk wrote:
>
>> at least they did not glue a bunch  of  gears on it and call it steam
>> punk...
>> I  have  run across  weird glued and punked items on   ebay...   what a
>> bunch
>> of   AH's
>>
>
> a model 026 punch is already a masterpiece of  steam punk.
>
> A model 029, on the other hand, appeals to  trekkies.
>
>
> I think that a keypunch rationalized as art  needs a clock on it:
>  http://www.ebay.com/itm/Melting-Clock-DT-/262670473087?hash=
>  item3d2861577f:g:kE4AAOSwONBZFFUo
>
>
> --
> Grumpy  Ol' Fred  ci...@xenosoft.com
>
>