søndag den 3. september 2023 kl. 21.20.59 UTC+2 skrev John Larkin:
> On Sun, 3 Sep 2023 12:28:44 -0400, Phil Hobbs
> <pcdhSpamM...@electrooptical.net> wrote:
>
> >On 2023-09-02 21:18, John Smiht wrote:
> >> On Saturday, September 2, 2023 at 6:06:21?PM UTC-5, Phil Hobbs wrote:
> >>
> >>> Before the vacuum-column tape transport was invented, early IBM tape drives
> >>> allegedly had an instruction SST, for “stop and stretch tape”.
> >>>
> >>> Cheers
> >>> Phil Hobbs
> >
> >>
> >> What about the instruction HCF? I think it was "halt and catch fire".
> >>
> >
> > From the Jargon File:
> >":HCF: /H·C·F/, n.
> >
> > Mnemonic for `Halt and Catch Fire', any of several undocumented and
> > semi-mythical machine instructions with destructive side-effects,
> > supposedly included for test purposes on several well-known
> > architectures going as far back as the IBM 360. The MC6800
> > microprocessor was the first for which an HCF opcode became widely
> > known. This instruction caused the processor to {toggle} a subset of
> > the bus lines as rapidly as it could; in some configurations this
> > could actually cause lines to burn up. Compare {killer poke}."
> >
> >Cheers
> >
> >Phil Hobbs
> I used 6800s and never heard of that. They were depletion-load PMOS
> parts, not CMOS, so overheating was unlikely.

https://x86.fr/investigating-the-halt-and-catch-fire-instruction-on-motorola-6800/

On Sunday, September 3, 2023 at 11:28:54 AM UTC-5, Phil Hobbs wrote:
> On 2023-09-02 21:18, John Smiht wrote:
> > On Saturday, September 2, 2023 at 6:06:21 PM UTC-5, Phil Hobbs wrote:
> >
> >> Before the vacuum-column tape transport was invented, early IBM tape drives
> >> allegedly had an instruction SST, for “stop and stretch tape”.
> >>
> >> Cheers
> >> Phil Hobbs
>
> >
> > What about the instruction HCF? I think it was "halt and catch fire".
> >
> From the Jargon File:
> ":HCF: /H·C·F/, n.
>
> Mnemonic for `Halt and Catch Fire', any of several undocumented and
> semi-mythical machine instructions with destructive side-effects,
> supposedly included for test purposes on several well-known
> architectures going as far back as the IBM 360. The MC6800
> microprocessor was the first for which an HCF opcode became widely
> known. This instruction caused the processor to {toggle} a subset of
> the bus lines as rapidly as it could; in some configurations this
> could actually cause lines to burn up. Compare {killer poke}."
> Cheers
>
> Phil Hobbs
>
> --
> Dr Philip C D Hobbs
> Principal Consultant
> ElectroOptical Innovations LLC / Hobbs ElectroOptics
> Optics, Electro-optics, Photonics, Analog Electronics
> Briarcliff Manor NY 10510
>
> http://electrooptical.net
> http://hobbs-eo.com

I did not know that! Fascinating.

On 2023-09-03 17:22, John Smiht wrote:
> On Sunday, September 3, 2023 at 11:28:54 AM UTC-5, Phil Hobbs wrote:
>> On 2023-09-02 21:18, John Smiht wrote:
>>> On Saturday, September 2, 2023 at 6:06:21 PM UTC-5, Phil Hobbs wrote:
>>>
>>>> Before the vacuum-column tape transport was invented, early IBM tape drives
>>>> allegedly had an instruction SST, for “stop and stretch tape”.
>>>>
>>>> Cheers
>>>> Phil Hobbs
>>
>>>
>>> What about the instruction HCF? I think it was "halt and catch fire".
>>>
>> From the Jargon File:
>> ":HCF: /H·C·F/, n.
>>
>> Mnemonic for `Halt and Catch Fire', any of several undocumented and
>> semi-mythical machine instructions with destructive side-effects,
>> supposedly included for test purposes on several well-known
>> architectures going as far back as the IBM 360. The MC6800
>> microprocessor was the first for which an HCF opcode became widely
>> known. This instruction caused the processor to {toggle} a subset of
>> the bus lines as rapidly as it could; in some configurations this
>> could actually cause lines to burn up. Compare {killer poke}."

>
> I did not know that! Fascinating.
>

The Jargon File is a good read, but more for the humor and general
atmosphere than for technical details. As JL says, it's fairly hard to
imagine a 6800 catching fire unless it was running an oven controller
when it locked up.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

On 2023-09-03, Jan Panteltje <alien@comet.invalid> wrote:
> On a sunny day (Sat, 02 Sep 2023 13:12:42 -0700) it happened John Larkin
><jlarkin@highlandSNIPMEtechnology.com> wrote in
><uh57fihhi4d8hc8u1k4o18o2qf79crilf9@4ax.com>:
>
>>On Sat, 2 Sep 2023 19:25:50 -0000 (UTC), Phil Hobbs
>><pcdhSpamMeSenseless@electrooptical.net> wrote:
>>
>>>John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
>>>> On Thu, 31 Aug 2023 12:05:31 +0100, piglet <erichpwagner@hotmail.com>
>>>> wrote:
>>>>
>>>>> On 31/08/2023 04:36, John Larkin wrote:
>>>>>>
>>>>>> (I had hernia surgery today and am still goofy from the drugs, so this
>>>>>> sort of nonsense fit right in.)
>>>>>>
>>>>>>
>>>>>
>>>>> Glad to have supplied some light relief!
>>>>>
>>>>> piglet
>>>>>
>>>>
>>>> Good quote, appropriate to that power supply:
>>>>
>>>>
>>>> It was the embodiment of the idea that perfection is not when there is
>>>> nothing left to add but when there is nothing left to take away.
>>>>
>>>> Keith Houston in Empire of the Sum
>>>>
>>>>
>>>>
>>>As the wise man said,
>>>
>>>“All programs have bugs, and all programs can be made smaller. Therefore
>>>all programs can be reduced to a single incorrect instruction.“
>>>
>>>Cheers
>>>
>>>Phil Hobbs
>>>
>>>Phil Hobbs
>>
>>PDP-11 had the RESET instruction. As in full hardware powerup-type
>>reset. Saved wear and tear on the power switch.
>>
>>It also has the Land Mine instruction,
>>
>>MOV -(PC), -(PC)
>>
>>which copied itself one word below, and executed from there.
>
> In linux systems you just type, as root, 'poweroff' in a terminal.
>
> As to starting anew with nothing:
> s u d o rm -rf /*
> remove spaces in 'sudo' (added those just to prevent poor creatures from doing a cut and paste)
> as it will erase everything on your system.

I tried

rm -rf /

yesterday, rm refused to comply I had to say

rm --no-preserve-root -rf /

> And yes, as I am always root, I once typed rm * -rf by accident while in /
> was quick to stop with ctrlC but hat to put back some X libraries...
>
> Do not try this at home.. ;-)

I was at work.

--
Jasen.
🇺🇦 Слава Україні

On a sunny day (Tue, 5 Sep 2023 04:28:59 -0000 (UTC)) it happened Jasen Betts
<usenet@revmaps.no-ip.org> wrote in <ud6aqb$2r1$3@gonzo.revmaps.no-ip.org>:

>On 2023-09-03, Jan Panteltje <alien@comet.invalid> wrote:
>> On a sunny day (Sat, 02 Sep 2023 13:12:42 -0700) it happened John Larkin
>><jlarkin@highlandSNIPMEtechnology.com> wrote in
>><uh57fihhi4d8hc8u1k4o18o2qf79crilf9@4ax.com>:
>>
>>>On Sat, 2 Sep 2023 19:25:50 -0000 (UTC), Phil Hobbs
>>><pcdhSpamMeSenseless@electrooptical.net> wrote:
>>>
>>>>John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
>>>>> On Thu, 31 Aug 2023 12:05:31 +0100, piglet <erichpwagner@hotmail.com>
>>>>> wrote:
>>>>>
>>>>>> On 31/08/2023 04:36, John Larkin wrote:
>>>>>>>
>>>>>>> (I had hernia surgery today and am still goofy from the drugs, so this
>>>>>>> sort of nonsense fit right in.)
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> Glad to have supplied some light relief!
>>>>>>
>>>>>> piglet
>>>>>>
>>>>>
>>>>> Good quote, appropriate to that power supply:
>>>>>
>>>>>
>>>>> It was the embodiment of the idea that perfection is not when there is
>>>>> nothing left to add but when there is nothing left to take away.
>>>>>
>>>>> Keith Houston in Empire of the Sum
>>>>>
>>>>>
>>>>>
>>>>As the wise man said,
>>>>
>>>>“All programs have bugs, and all programs can be made smaller. Therefore
>>>>all programs can be reduced to a single incorrect instruction.“
>>>>
>>>>Cheers
>>>>
>>>>Phil Hobbs
>>>>
>>>>Phil Hobbs
>>>
>>>PDP-11 had the RESET instruction. As in full hardware powerup-type
>>>reset. Saved wear and tear on the power switch.
>>>
>>>It also has the Land Mine instruction,
>>>
>>>MOV -(PC), -(PC)
>>>
>>>which copied itself one word below, and executed from there.
>>
>> In linux systems you just type, as root, 'poweroff' in a terminal.
>>
>> As to starting anew with nothing:
>> s u d o rm -rf /*
>> remove spaces in 'sudo' (added those just to prevent poor creatures from doing a cut and paste)
>> as it will erase everything on your system.
>
>I tried
>
> rm -rf /
>
>yesterday, rm refused to comply I had to say
>
> rm --no-preserve-root -rf /

Modern versions of Linux keep amazing me!
That 'rm' I did was maybe 15 or 20 years ago.

There is so much crap build into today's Linux distros.. utilities
I find for example Ubuntu, that I just installed on my laptop,
a disaster.
Not only does it not allow root to run X programs, it also does
sneaky automatic updates, and if you switch that off, then it has something called 'snap'
that will do updates by itself.
Debian is more sane...

My thought was, after fighting 2 days with Ubuntu , that Linux is dead.
There are fortunately other distros..
The other news I did read is that Linux wants to stop supporting reiserfs in the kernel.
Now Reiserfs is a magnitude more reliable than what distros come with these days
I have it on several systems and many backups ..
Never a problem, ext4 has a lot of strange problems.
So, Unix, the old Unix , .. it was good.
I have SLS Linux from 1998 on a floppy somewhere..

Kiddies now add their own take on it while not understanding the basics IMO.
Same for a lot of other software and libraries.
So a good clean Unix must be somewhere to be found.

Do they drop reiserfs because the poor guy is in jail?
Politics into technology? What about people's backups?
Sell more storage media? Bloat sells, the more stupid mods to Linux the more
updates needed the more bandwidth needed so you have to buy into 5G and fiber...
As you can see from this reply I am all for going back to smoke signals.
Works even from the moon to earth if the smoke clouds are big enough.

>> And yes, as I am always root, I once typed rm * -rf by accident while in /
>> was quick to stop with ctrlC but hat to put back some X libraries...
>>
>> Do not try this at home.. ;-)
>
>I was at work.

Yea, sorry ;-)

On 31/08/2023 3:31 pm, Fred Bloggs wrote:
> On Thursday, August 31, 2023 at 7:03:29 AM UTC-4, piglet wrote:
>> On 30/08/2023 23:50, Fred Bloggs wrote:
>>> On Wednesday, August 30, 2023 at 5:11:38 PM UTC-4, piglet wrote:
>>>> Pardon a post about electronic design. In a recent Dave Jones EEVBlog
>>>> video nr 1561 ...
>>>>
>>>> <https://www.youtube.com/watch?v=FKC6lnTKH-c>
>>>>
>>>> ... he shows his USB powered variable bench power supply. At about 28:10
>>>> the regulator schematic is shown. I am baffled why he uses two series
>>>> pass transistors; one for current, one for voltage. I cannot recall ever
>>>> seen the functionality split into two power transistors in series
>>>> before. Is that laziness or brilliance? Does anyone have ideas about the
>>>> design reasoning?
>>>
>>> They use similar in HP benchtops. It's necessary if you want a precision programmable current limit. Until it limits, it's just a saturated FET putting most of the voltage on the voltage regulation FET.
>>>
>>>>
>>>> Diode D4 in the voltage regulator does not inspire confidence.
>>>
>>> Note on schematic says D4 prevents interference by input diodes ( of error opamp ) on the voltage measurement, meaning at R22+ R23 junction. If I could read the pn of the op amp it would be clear, but it's not readable as is. Maybe it's some quasi-Norton amp. Whatever it is the input is acting on about a diode drop below the voltage at external (+) input.
>>>
>>> Schematic symbols of resistors look like inductors. FETs look like RJ-45 connectors.
>>>
>>>>
>>>> piglet
>> The opamp is OPA2180 zero drift/auto zero type with inverse parallel
>> input protection diodes. D4 looks mega kludgy - if it were mine I'd
>> investigate using a different opamp or taking the error signal from the
>> voltage follower used for metering. Still I guess in real life the
>> voltage drop error across D4 at nanoamp opamp input bias current is near
>> negligible?
>
> None of what he has makes any sense, neither D4 nor that 2kR resistor. What's probably going on is he's hitting the Vset input with too large a step from his D/A, and that's causing the differential clamp diodes to conduct and produce screwy outputs until the loop recovers. He should limit his steps to say 50mV and allow settling time of 5x of what he's pre-measured before applying another one. Get rid of D4 and the 2k.
>
>
>>
>> piglet

I don't think it is do with settling time or steps - simply that when
the output is shorted (or otherwise much lower than the set output
voltage) then the op-amp clamp diodes will let Vset from the DAC flow
into the voltage divider measurement node and cause the wrong output
voltage to be displayed. What is the 2kR resistor you refer to? I see
R23 which is 10Megaohm.

The D4 kludge is truly appalling.

piglet

PS
just now I encountered an other insane Linux thing:
To make pdf files from JPG pictures you used to be able to write
convert *.JPG outfile2.pdf
that uses 'convert', part of the Imagemagic program.
Was I surprised it refused with a security message on my latest Raspberry when root.

So web search showed you need to modify
/etc/ImageMagick-6/policy.xml
and change 'none' to 'read|write" to enable pdf output in this line:
<policy domain="coder" rights="read|write" pattern="PDF" />

Of course making a pdf is extremely dangerous?
What a bunch of idiots have had a go at Linux distros.
The real security issues they do not even see, have no clue about.
That is likely why half the world is hacked now , including the brains of US leaders and many software developers...

Next thing you need a password for you windshield wipers? Or is that already ?

Of course 'convert' is not the best way to make pdfs, but lots of Chinese stuff comes with manuals the size of a postage stamp
in Chinglish .. so I take JPG pictures of the pages (six in this case) with a real camera (Canon) and make a pdf manual I keep around
and can display any size I want to make it readable.

VERY dangerous, making a pdf..

Now wait for your peeseebee layout program to refuse to make one...

And all the waisted time to find out how to fix the crap.