RE: Looking for Philips P2000C P-Systems discs

[Rik Bos]

> pic?
> 
Like this ?
http://www.computinghistory.org.uk/det/14769/Philips-P2000C-P2012/

-Rik

Re: Thinking about acquiring PDP stuff

[John H. Reinhardt]

On 12/1/2016 2:22 AM, jim stephens wrote:


Very true, but didn't honestly think of that in context of the
thread, nor have I ever had any Digital Group stuff.  And does any
Digital Group cause any injuries requiring orthopedic medical
attention when you are lifting it?

thanks jim


Only borderline, I think the total weight of the system box was around 40lbs.  The 
standard box was a little bigger than the Altair 8800, I think.  Wider by about 10" 
or so.  I built a bunch of their kits when I was 17/18 before I went to college.  Tried 
to make my own chassis and P/S but finally had to give in and buy the dg one.  I had a 
2.5Mhz Z80a, 26kB ( 3x8k +2k on CPU board) memory, an audio cassette tape storage 
interface and a Panasonic 12 (13"?) B/W TV cobbled into a surplus DEC VT52 style 
case that I bought from that famous (in the 70's) surplus place in Massachusetts. Poly 
Paks*? I can't remember the name.

I kind of wish I still had that system.  But after college, I never was back 
near home and eventually my parents asked if it was okay to sell it and I gave 
them permission.  someone packed it up and hauled it off. I hope it's still out 
there somewhere.

John H. Reinhardt


*Yes, Poly Paks.  Found a discussion  

I also bought an old vector display unit from then, there as an article in Byte 
about turning one into a display and playing Space War on it.  Never got it to 
work though. Parents sold it off either when I was away in college or after I 
graduated and wasn't at home.

RE: PDP-8e power switch key?

[W2HX]

Hey all,

Thanks to everyone for the response on keys. I am sorry I don’t know how I 
missed all the collected information here on this subject. My apologies. I now 
have all the information I need on this subject! Thanks everyone.
Eugene


-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Ethan Dicks
Sent: Thursday, December 01, 2016 12:07 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: PDP-8e power switch key?

On Wed, Nov 30, 2016 at 11:35 PM, W2HX  wrote:
> Hi folks,
>
> What are people doing for keys for the 8e?

I've been carrying a standard DEC key on my keyring since 1982...

> Is there a standard key used for all of them?

Nearly all (a custom key was an option - I have only ever seen *1* DEC machine 
that does not use either an ACE XX2247 or a pinless key, out of many dozens).

> Or do I need to have one made with some specific serial number of my key 
> lock?  I did some googling of this issue but wasn't able to get info.

There should be _lots_ of info on DEC ACE XX2247 keys including pin depths and 
even 3D models.

-ethan

Re: Thinking about acquiring PDP stuff

[allison]

On 11/30/16 3:15 PM, Rich Alderson wrote:

From: Brad H
Sent: Wednesday, November 30, 2016 9:16 AM


That was kind of why I thought buying a PDP in pieces over time might be my
way to go, even if it took eons to get everything I needed to rebuild one.
It'd be fun to try and piece one back together.  But yeah, I'm trying to
think of what I would do with it afterwards. :)

So what kind of system are you interested in?  There is no such thing as a
generic "PDP".  Before giving up the naming convention, DEC produced 7
different architectures all named "PDP-n" for small integers n (and designed 2
that were never built by DEC):

PDP-1:  18 bits, 6 instruction + 12 address (System Modules)
PDP-2:  24 bits (design only) (System Modules)
PDP-3:  36 bits (design only) (System Modules)
PDP-4:  18 bits, 5 instruction + 13 address (System Modules)
PDP-5:  12 bits (System Modules)
PDP-6:  36 bits, 9 instruction, 9 AC+index+indirect, 18 address (mainframe)
PDP-7:  18 bits (PDP-4 upwards compatible) (FlipChips)
PDP-8:  12 bits (PDP-5 upwards compatible) (FlipChips)
PDP-9:  18 bits (PDP-7 upwards compatible) (FlipChips)
PDP-10: 36 bits (PDP-6 upwards compatible) (mainframe)
PDP-11: 16 bits (FlipChips)
PDP-12: 12 bits (PDP-8 + LINC compatible) (FlipChips)
PDP-14: 12 bits (NOT compatible with the PDP-8 family) (FlipChips)
PDP-15: 18 bits (PDP-9 upwards compatible) (FlipChips)
PDP-16: register-transfer module machine, with 8-, 12- or 16-bit memory as
needed for particular application design.

Later members of each family were designated by suffixes (e.g. 8/i, 8/e, 8/A
and 11/40, 11/70, etc.) or newer names (DECsystem-10, DECSYSTEM-20).  The VAX
was the first new architecture from DEC not to have a PDP-n designation at all.

 Rich

P. S. For most of us, I think, "DG" = Data General, not Digital Group.


Rich Alderson
Vintage Computing Sr. Systems Engineer
Living Computer Museum
2245 1st Avenue S
Seattle, WA 98134

mailto:ri...@livingcomputermuseum.org

http://www.LivingComputerMuseum.org/


Rich,

You missed posting approximate volumes made. Some of those like the 
PDP1,4, 6 and 12

have very low production volumes.

Yes on DG, however there are use that did play with Digital Group.
A Digital group system fully bown out is likely about 60 pounds or so.
They were on a par with other S100 8080 systems for size and weight.

Allison

RE: Thinking about acquiring PDP stuff

[Brad H]

-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of John H. 
Reinhardt
Sent: Thursday, December 1, 2016 5:18 AM
To: General Discussion: On-Topic and Off-Topic Posts 
Subject: Re: Thinking about acquiring PDP stuff


On 12/1/2016 2:22 AM, jim stephens wrote:

> Very true, but didn't honestly think of that in context of the thread, 
> nor have I ever had any Digital Group stuff.  And does any Digital 
> Group cause any injuries requiring orthopedic medical attention when 
> you are lifting it?
>
> thanks jim

Only borderline, I think the total weight of the system box was around 40lbs.  
The standard box was a little bigger than the Altair 8800, I think.  Wider by 
about 10" or so.  I built a bunch of their kits when I was 17/18 before I went 
to college.  Tried to make my own chassis and P/S but finally had to give in 
and buy the dg one.  I had a 2.5Mhz Z80a, 26kB ( 3x8k +2k on CPU board) memory, 
an audio cassette tape storage interface and a Panasonic 12 (13"?) B/W TV 
cobbled into a surplus DEC VT52 style case that I bought from that famous (in 
the 70's) surplus place in Massachusetts. Poly Paks*? I can't remember the name.

I kind of wish I still had that system.  But after college, I never was back 
near home and eventually my parents asked if it was okay to sell it and I gave 
them permission.  someone packed it up and hauled it off. I hope it's still out 
there somewhere.

John H. Reinhardt


>*Yes, Poly Paks.  Found a discussion  
>
>I also bought an old vector display unit from then, there as an article in 
>Byte about turning one into a display and playing Space War on it.  Never got 
>it to >work though. Parents sold it off either when I was away in college or 
>after I graduated and wasn't at home.

I have the Basic Box and it's not very heavy at all relatively speaking.  I 
imagine the Bytemaster, with the built in monitor probably weighs a fair bit.  
My Intellec 230 though might give a PDP a run for its money.

RE: PDP-8e power switch key?

[Fred Cisin]

On Thu, 1 Dec 2016, W2HX wrote:
Thanks to everyone for the response on keys. I am sorry I don’t know 
how I missed all the collected information here on this subject. My 
apologies. I now have all the information I need on this subject! Thanks 
everyone.


If you can, you should remove the lock and take it with you to the 
locksmith when you go to get your xx2247 key made.


1) It makes it convenient to test the newly-cut key, and/or resolve any 
uncertainties about it.


2) In SOME jusrisdictions, there are local regulations forbidding 
code-cutting of keys, without varying levels of PROOF that you own/have 
said lock.  That is nominally so that, since many locks have their 
code-name displayed, that somebody doesn't walk into a locksmith and get 
keys cut for other people's locks.



5 years ago, in the previous discussion of the XX2247, a couple of people 
measured their keys.  If you don't have a code-cutting locksmith handy, 
those discussions were just about all you would need to machine your own 
blank and cut it yourself.



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

Re: PDP-8e power switch key?

[william degnan]

On Thu, Dec 1, 2016 at 11:57 AM, Fred Cisin  wrote:

> On Thu, 1 Dec 2016, W2HX wrote:
>
>> Thanks to everyone for the response on keys. I am sorry I don’t know how
>> I missed all the collected information here on this subject. My apologies.
>> I now have all the information I need on this subject! Thanks everyone.
>>
>
> If you can, you should remove the lock and take it with you to the
> locksmith when you go to get your xx2247 key made.
>
> 1) It makes it convenient to test the newly-cut key, and/or resolve any
> uncertainties about it.
>
> 2) In SOME jusrisdictions, there are local regulations forbidding
> code-cutting of keys, without varying levels of PROOF that you own/have
> said lock.  That is nominally so that, since many locks have their
> code-name displayed, that somebody doesn't walk into a locksmith and get
> keys cut for other people's locks.
>
>
> 5 years ago, in the previous discussion of the XX2247, a couple of people
> measured their keys.  If you don't have a code-cutting locksmith handy,
> those discussions were just about all you would need to machine your own
> blank and cut it yourself.
>
>
> --
> Grumpy Ol' Fred ci...@xenosoft.com


There is a key depository that I believe you can locate within the DEC
section of the vcfed.org/forum/ user group..
b

Re: PDP-8e power switch key?

[Mark G Thomas]

Hi,

On Wed, Nov 30, 2016 at 08:35:31PM -0800, W2HX wrote:
> Hi folks,
> 
> What are people doing for keys for the 8e? Is there a standard key used for 
> all of them? Or do I need to have one made with some specific serial number 
> of my key lock?  I did some googling of this issue but wasn't able to get 
> info.
> 
> Thanks
> Eugene W2HX

I bought one of these for $18.47 for my 8/e, and it works fine.

 http://www.ebay.com/itm/142118132040

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Re: PDP-8e power switch key?

[Marc Howard]

A long, long time ago (1978, 79?) when I had a straight 8 and our group had
a new VAX 11/780 I verified that the same key works on both machines.

On Thu, Dec 1, 2016 at 9:13 AM, Mark G Thomas  wrote:

> Hi,
>
> On Wed, Nov 30, 2016 at 08:35:31PM -0800, W2HX wrote:
> > Hi folks,
> >
> > What are people doing for keys for the 8e? Is there a standard key used
> for all of them? Or do I need to have one made with some specific serial
> number of my key lock?  I did some googling of this issue but wasn't able
> to get info.
> >
> > Thanks
> > Eugene W2HX
>
> I bought one of these for $18.47 for my 8/e, and it works fine.
>
>  http://www.ebay.com/itm/142118132040
>
> Mark
>
> --
> Mark G. Thomas (m...@misty.com), KC3DRE
>

Winchester-style coax connectors?

[Josh Dersch]

Hey all --

Due to a small miracle I now have 8KW of perfectly functioning core in my
long-ill Imlac PDS-1D.  The last hurdle is devising a replacement for the
missing display (an X/Y vector display).  For the time being I'm going to
attempt to use an oscilloscope, but first I need to build a cable.

The Imlac uses a Winchester connector (14 position) for the display and
while they're not as common these days the parts can still be found so I
thought I was in the clear, but what I failed to notice is that three of
the "pins" (for the X, Y and Blank signals) are actually tiny coaxial
connectors that fit within the Winchester housing (i.e. they're the same
diameter as a Winchester pin).

I haven't been able to track these connectors down anywhere.  Anyone have
any ideas?

Failing that, I can always just tap into the backplane to pick up these
signals and ignore the connector on the bulkhead, but it would be nice to
be able to use the original connector...

- Josh

Re: Winchester-style coax connectors?

[Paul Koning]

> On Dec 1, 2016, at 2:27 PM, Josh Dersch  wrote:
> 
> ...
> The Imlac uses a Winchester connector (14 position) for the display and
> while they're not as common these days the parts can still be found so I
> thought I was in the clear, but what I failed to notice is that three of
> the "pins" (for the X, Y and Blank signals) are actually tiny coaxial
> connectors that fit within the Winchester housing (i.e. they're the same
> diameter as a Winchester pin).

What is a "Winchester connector"?  Do you mean a D-sub connector, i.e., with a 
trapezoidal shell such as you find on terminal or VGA connectors?  Those come 
in a number of widths, with names like DE (for the VGA size), or DB (the 25 pin 
classic RS-232), and so forth.  Often, incorrectly, all are called DB.

Those shells have a variety of choices for pins.  They may be two rows of pins 
(e.g., DB-25), or 3 rows (e.g., DE-15).  You may also find ones that have just 
miniature coax inserts, or a mix of coax and plain pins.  The coax inserts are 
generally larger, such that it takes up much of the height of the connector.  I 
haven't seen coax pins that are the same diameter as plain signal pins, that's 
rather hard to imagine especially for something as old as an Imlac.  Examples 
of mixed pin D-sub connectors are the Sun video monitor connectors, with RGB on 
coax.

paul

Re: Winchester-style coax connectors?

[Josh Dersch]

On Thu, Dec 1, 2016 at 11:47 AM, Paul Koning  wrote:

>
> > On Dec 1, 2016, at 2:27 PM, Josh Dersch  wrote:
> >
> > ...
> > The Imlac uses a Winchester connector (14 position) for the display and
> > while they're not as common these days the parts can still be found so I
> > thought I was in the clear, but what I failed to notice is that three of
> > the "pins" (for the X, Y and Blank signals) are actually tiny coaxial
> > connectors that fit within the Winchester housing (i.e. they're the same
> > diameter as a Winchester pin).
>
> What is a "Winchester connector"?  Do you mean a D-sub connector, i.e.,
> with a trapezoidal shell such as you find on terminal or VGA connectors?
> Those come in a number of widths, with names like DE (for the VGA size), or
> DB (the 25 pin classic RS-232), and so forth.  Often, incorrectly, all are
> called DB.
>
> Those shells have a variety of choices for pins.  They may be two rows of
> pins (e.g., DB-25), or 3 rows (e.g., DE-15).  You may also find ones that
> have just miniature coax inserts, or a mix of coax and plain pins.  The
> coax inserts are generally larger, such that it takes up much of the height
> of the connector.  I haven't seen coax pins that are the same diameter as
> plain signal pins, that's rather hard to imagine especially for something
> as old as an Imlac.  Examples of mixed pin D-sub connectors are the Sun
> video monitor connectors, with RGB on coax.
>
> paul
>
>
>

Like one of these bad-boys, only with 14 connectors rather than 34:

http://cables24.com/en/others/cable-v-35/1470-V-35-m34-Winchester-34pin-male-connector

Sorry for not being more specific.  The coax connectors in a 13W3 connector
(for example) are much larger than what I need.

- Josh

Re: Winchester-style coax connectors?

[Tom Uban]

Have you considered using a vector arcade game monitor?

On 12/1/16 1:27 PM, Josh Dersch wrote:
> Hey all --
> 
> Due to a small miracle I now have 8KW of perfectly functioning core in my
> long-ill Imlac PDS-1D.  The last hurdle is devising a replacement for the
> missing display (an X/Y vector display).  For the time being I'm going to
> attempt to use an oscilloscope, but first I need to build a cable.
> 
> The Imlac uses a Winchester connector (14 position) for the display and
> while they're not as common these days the parts can still be found so I
> thought I was in the clear, but what I failed to notice is that three of
> the "pins" (for the X, Y and Blank signals) are actually tiny coaxial
> connectors that fit within the Winchester housing (i.e. they're the same
> diameter as a Winchester pin).
> 
> I haven't been able to track these connectors down anywhere.  Anyone have
> any ideas?
> 
> Failing that, I can always just tap into the backplane to pick up these
> signals and ignore the connector on the bulkhead, but it would be nice to
> be able to use the original connector...
> 
> - Josh
> 

Re: Winchester-style coax connectors?

[jim stephens]

On 12/1/2016 11:51 AM, Josh Dersch wrote:

On Thu, Dec 1, 2016 at 11:47 AM, Paul Koning  wrote:


On Dec 1, 2016, at 2:27 PM, Josh Dersch  wrote:

...
The Imlac uses a Winchester connector (14 position) for the display and
while they're not as common these days the parts can still be found so I
thought I was in the clear, but what I failed to notice is that three of
the "pins" (for the X, Y and Blank signals) are actually tiny coaxial
connectors that fit within the Winchester housing (i.e. they're the same
diameter as a Winchester pin).

What is a "Winchester connector"?  Do you mean a D-sub connector, i.e.,
with a trapezoidal shell such as you find on terminal or VGA connectors?
Those come in a number of widths, with names like DE (for the VGA size), or
DB (the 25 pin classic RS-232), and so forth.  Often, incorrectly, all are
called DB.

Those shells have a variety of choices for pins.  They may be two rows of
pins (e.g., DB-25), or 3 rows (e.g., DE-15).  You may also find ones that
have just miniature coax inserts, or a mix of coax and plain pins.  The
coax inserts are generally larger, such that it takes up much of the height
of the connector.  I haven't seen coax pins that are the same diameter as
plain signal pins, that's rather hard to imagine especially for something
as old as an Imlac.  Examples of mixed pin D-sub connectors are the Sun
video monitor connectors, with RGB on coax.

 paul




Like one of these bad-boys, only with 14 connectors rather than 34:

http://cables24.com/en/others/cable-v-35/1470-V-35-m34-Winchester-34pin-male-connector

Sorry for not being more specific.  The coax connectors in a 13W3 connector
(for example) are much larger than what I need.

- Josh
Try Electro Mavin.  He's been buying and squirreling away connectors for 
40 or 50 years.  I don't know any other vendor with as much stock as he has.


You may need to bull  your way thru to him or his daughter or other 
person in the know for connectors, but he is your best shot.


http://www.mavin.com/

I've seen him pay serious money for connectors at various swap meets 
around LA and in other transactions where connectors were up for grabs.


thanks
jim

Digital circuits and analog devices

[Noel Chiappa]

So I have this memory of a set of law promulgated by an engineer at DEC, one
of which was something to the effect that 'all digital circuits are made out
of analog devices'. However, my memory doesn't recall where I saw this, and my
Google-fu is not strong enough to turn it up. Can anyone help?

Noel

RE: Digital circuits and analog devices

[W2HX]

Not only are they made of analog devices, but at the speeds things have been 
running at for the last 20 (maybe 30) years, they often behave like analog 
devices. Things like transmission line theory, crosstalk, oscillation, etc are 
all important design considerations.
Eugene


-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Noel Chiappa
Sent: Thursday, December 01, 2016 9:31 PM
To: cctalk@classiccmp.org
Cc: j...@mercury.lcs.mit.edu
Subject: Digital circuits and analog devices

So I have this memory of a set of law promulgated by an engineer at DEC, one of 
which was something to the effect that 'all digital circuits are made out of 
analog devices'. However, my memory doesn't recall where I saw this, and my 
Google-fu is not strong enough to turn it up. Can anyone help?

Noel

Re: Digital circuits and analog devices

[drlegendre .]

You don't really find many examples of discrete states, anywhere in the
natural world. Just not a whole lot of quantization out there, unless you
reduce to the subatomic level - and while you'll find discrete states
(quanta) there, they are by nature indeterminate.

Have to admit, we did get an interesting universe.



On Thu, Dec 1, 2016 at 8:34 PM, W2HX  wrote:

> Not only are they made of analog devices, but at the speeds things have
> been running at for the last 20 (maybe 30) years, they often behave like
> analog devices. Things like transmission line theory, crosstalk,
> oscillation, etc are all important design considerations.
> Eugene
>
>
> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Noel
> Chiappa
> Sent: Thursday, December 01, 2016 9:31 PM
> To: cctalk@classiccmp.org
> Cc: j...@mercury.lcs.mit.edu
> Subject: Digital circuits and analog devices
>
> So I have this memory of a set of law promulgated by an engineer at DEC,
> one of which was something to the effect that 'all digital circuits are
> made out of analog devices'. However, my memory doesn't recall where I saw
> this, and my Google-fu is not strong enough to turn it up. Can anyone help?
>
> Noel
>

Re: Digital circuits and analog devices

[Chuck Guzis]

On 12/01/2016 06:31 PM, Noel Chiappa wrote:
> So I have this memory of a set of law promulgated by an engineer at
> DEC, one of which was something to the effect that 'all digital
> circuits are made out of analog devices'. However, my memory doesn't
> recall where I saw this, and my Google-fu is not strong enough to
> turn it up. Can anyone help?

I don't know if he was the first--probably not--but the late Bob Pease
often echoed the sentiment.  Of course, his specialty was analog design...

--Chuck

RE: Thinking about acquiring PDP stuff

[Rich Alderson]

From: Brad H
Sent: Thursday, December 01, 2016 8:18 AM

> My Intellec 230 though might give a PDP a run for its money.

See, I'm trying to get you to stop saying "a PDP".  There's no such thing.
There are families of PDP-n things, but there are wide differences in size,
weight, and capabilities.

Your Intellec 230 would fit inside one memory cabinet of a PDP-10 with
room to spare.  The entire PDP-10 system weighs tons.

Rich



Rich Alderson
Sr. Systems Engineer
Living Computers: Museum + Labs
2245 1st Ave S
Seattle, WA 98134

http://www.LivingComputers.org/

Re: Winchester-style coax connectors?

[Pete Lancashire]

Can you take a  picture of the side you have ? I have a few

On Dec 1, 2016 11:27 AM, "Josh Dersch"  wrote:

Hey all --

Due to a small miracle I now have 8KW of perfectly functioning core in my
long-ill Imlac PDS-1D.  The last hurdle is devising a replacement for the
missing display (an X/Y vector display).  For the time being I'm going to
attempt to use an oscilloscope, but first I need to build a cable.

The Imlac uses a Winchester connector (14 position) for the display and
while they're not as common these days the parts can still be found so I
thought I was in the clear, but what I failed to notice is that three of
the "pins" (for the X, Y and Blank signals) are actually tiny coaxial
connectors that fit within the Winchester housing (i.e. they're the same
diameter as a Winchester pin).

I haven't been able to track these connectors down anywhere.  Anyone have
any ideas?

Failing that, I can always just tap into the backplane to pick up these
signals and ignore the connector on the bulkhead, but it would be nice to
be able to use the original connector...

- Josh

Re: ISO Xebec S1410A fw #104792 or 104793

[David Cooper]

I have imaged a couple of ROMS from Xebec Controllers:

ASSY 104527 REV E06, SN 132-2860\xebec_104521h_adb5_TMS2732AJL-45.bin
104686, ROM 104700A (mfm-scsi bridge)\104700a_xebec_assy104686.bin

Do either of these look like something you would like?





-Original Message- 
From: Al Kossow

Sent: Monday, November 14, 2016 5:57 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: ISO Xebec S1410A fw #104792 or 104793

I just started cataloging and dumping firmware my SASI/SCSI disk and tape 
boards
starting with Xebec. It would be nice to find images for the two alternate 
fw
proms for the S1410A, particularly the 8k 104793 version so I can compare it 
to

the one used on the S1420

Re: Digital circuits and analog devices

[Tony Duell]

On Fri, Dec 2, 2016 at 2:31 AM, Noel Chiappa  wrote:
> So I have this memory of a set of law promulgated by an engineer at DEC, one
> of which was something to the effect that 'all digital circuits are made out
> of analog devices'. However, my memory doesn't recall where I saw this, and my
> Google-fu is not strong enough to turn it up. Can anyone help?

It's one of Don Vonada's laws. I am pretty sure I first read them in
'Computer Engineering', that book produced by DEC. I think the
original is 'Digital circuits are made from analog parts'

Another of the laws is 'There is no such thing as ground' which

(a) means voltmeters have 2 leads, so you can take whatever
you want as a reference

and

(b) all connections have impedance (the inductance is the important
bit in general) so even if you have 2 points connected to a wire you
call 'ground' they won't necessarily be at the same voltage all the time.

A related one, which I don't know if it was ever written down in an
official book (he told it to me in person) came from Professor M. V. Wilkes

'A digital circuit is like a tame animal. An analogue circuit is like a
wild animal. Every so often the tame animal goes back to the wild'

-tony

-tony

>
> Noel

Re: Digital circuits and analog devices

[Eric Smith]

On Thu, Dec 1, 2016 at 10:59 PM, Tony Duell  wrote:

> It's one of Don Vonada's laws. I am pretty sure I first read them in
> 'Computer Engineering', that book produced by DEC. I think the
> original is 'Digital circuits are made from analog parts'
>
> Another of the laws is 'There is no such thing as ground' which
>

That's where I saw them also.  The full set from the book (any typos are
mine):

Vonada's Engineering Maxims

1. There is no such thing as ground.
2. Digital circuits are made from analog parts.
3. Prototype designs always work.
4. Asserted timing conditions are designed first; unasserted timing
conditions are found later.
5. When all but one wire in a group of wires switch, that one will switch
also.
6. When all but one gate in a module switches, that one will switch also.
7. Every little pico farad has a nano henry all its own.
8. Capacitors convert voltage glitches to current glitches (conservation of
energy).
9. Interconnecting wires are probably transmission lines.
10. Synchronizing circuits may take forever to make a decision.
11. Worse-case tolerances never add -- but when they do, tehy are found in
the best customer's machine.
12. Diagnostics are highly efficient in finding solved problems.
13. Processing systems are only partially tested since it is impractical to
simulate all possible machine states.
14. Murphy's Laws apply 95 percent of the time. The other 5 percent of the
time is a coffee break.