* Posts by swm

995 publicly visible posts • joined 6 Jun 2015


Wayland takes the wheel as Red Hat bids farewell to X.org


But can you tunnel wayland over ssh

This is needed for sanity.

User read the manual, followed instructions, still couldn't make 'Excel' work


Re: Click, click, click, nothing happens

There was a screen saver that took a snapshot of the screen and slowly random bits on the screen would drop down to the next non-white bit below. Eventually there was a set of pixels at the bottom of the screen where all of the bits came to rest.

Another screen saver took a snapshot of the screen and slowly caused the image to "melt" causing weird distortions of the screen.

Revival of Medley/Interlisp: Elegant weapon for a more civilized age sharpened up again


Re: You /what/ Liam?

It is interlisp. I used it for many years at Xerox as my desktop. It had mail, text editing, a couple of lisp structure editors, etc. in fact, everything you needed to get your work done. If it crashed (e.g., due to building power failure), when it came up all of your windows were just where you left them.

I still miss it (and Smalltalk 76).

Don't fear the Thread Reaper, a Windows ghost of bugs past


Re: It should never happen, hence the bug check

Then there was a bug in the early MULTICS system where the swap out module swapped out the swap in module.

Making the problem go away is not the same thing as fixing it


At Xerox they piped in musak through the same speakers used for alerts. I watched a scientist snip wires until the musak was gone. Xerox finally wised up and put a switch to turn off the musak.

Workload written by student made millions, ran on unsupported hardware, with zero maintenance


Re: A quick question

It's not still in use but I wrote the executive for the second time sharing system (around 1970) at Dartmouth and it was still running 25+ years later.

Colleges snub Turnitin's AI-writing detector over fears it'll wrongly accuse students


Re: If it's as good as their other products...

When I taught computer science all of the students' submissions were run through a cheating detection program which gave a score between submissions. One term the checker flagged two of my students of having a very high degree of similarity, it was, in fact, the highest score that term.

So I printed out both submissions, did a diff (which showed nothing). I then looked closely at the two codes and noticed that the students were using a totally different approach. If they did copy code it would have been useless.

So I went back to the cheating checker output. It basically looked for syntactic similarities. Both students used a lot of System.out.println s for debugging and the cheating checker had matched them all up even though they were printing different things.

So I just threw everything in the trash and never mentioned it to the students involved.

Getting to the bottom of BMW's pay-as-you-toast subscription failure


Re: if you tolerate this then your chilled air will be next.

Dartmouth created a time sharing system in 1964. It ran on a GE-225. It was later upgraded to a GE-235 which was three times faster and had more instructions. Of course the students used all of the extra instructions on the GE-235.

Since this was done on an NSF grant everything was public. Someone in GE got the idea of selling time sharing systems. So they got a GE-225 (and DN-30 etc.) and all of the source code. At which time they discovered that the code wouldn't run because of the use of GE-235 instructions. So they replaced the GE-225 with a GE-235 and put a wait loop in the executive to slow the machine down to GE-225 speeds. The code was labeled for exactly what it did. The customer was happy, GE was happy, and a lot of useless cycles were burned in the wait loop.

Chap blew up critical equipment on his first day – but it wasn't his volt


Re: Should this be so easy?

In the early days at college there was a planned power outage so we got a generator to run the studio. We then pulled the main breaker and made an extension cord with male plugs on both ends. one was plugged into the generator and the other into a convenient wall socket. Everything worked except the zip cord between the two plugs was quite warm to the touch. We had to be careful not to bunch up the zip cord to keep the temperature down. The generator was fueled with gasoline which we kept in glass jugs which we filled at the local gas station.

I'm glad OSHA wasn't around then.

Extra points: count the number of safety principles that were violated.


Re: electron volts per electron

Electron volts are a measure of energy but mass is energy. In high-energy physics mass is routinely measured in electron-volts.

I'll see your data loss and raise you a security policy violation


Re: Outlook...

This was my strategy for paper documents. I would have several piles of papers, notes etc. in my office. I could remember which pile a document lived and using the principle of 1 inch per month allowed me to retrieve documents quickly.

The clean desk policy idiots didn't like this but, since they couldn't find anything in my office, I got a conditional pass.

Japan complains Fukushima water release created terrifying Chinese Spam monster


Re: Be fair:

The simulator that the Three Mile Island operators were trained on could not simulate the actual occurrence. Therefore the operators could not have been trained for this problem.

Windows screensaver left broadcast techie all at sea


Re: Not a screen saver, but...

There was a FORTRAN compiler that would emit a message "error #2 - do loop nesting ..." (I forget the whole message.) We all wondered what error #1 was until one day there was a big laugh: Error #1 was "END is not last."

India lands Chandrayaan-3 spacecraft on Moon, is the first to lunar south pole


I second this. Congratulations to India for a great mission. They deserve more than one beer.

Lesson 1: Keep your mind on the ... why aren't the servers making any noise?


Re: Circuit Breakers

A lot of large squirrel cage motors have resistance for startup which is switched out once the motor is up to speed.

Resilience is overrated when it's not advertised


Re: Fallback fault-tolerant

At the school where I taught the file server was named Mordor but was eventually replaced with Gondor.

The price of freedom turned out to be an afternoon of tech panic


Re: Spreadsheet imports

I remember at the college where I taught, one of the professors moved a column vertically in a spread sheet and excel helpfully tracked all of the cell bindings to their new location.

When I did grading with a spread sheet I always added a perfect student. If this student didn't get 100% after all of the formula crunching I knew something was wrong.

How to get a computer get stuck in a lift? Ask an 'illegal engineer'


Re: 402 story

The "S2" relay? Probably because you didn't pay for a full-speed machine and this relay was part of the slow down "fix" to make the machine run at the speed you paid for.


Re: Getting stuck in a lift is no fun

I knew someone who was a volunteer fireman. He said they once got a fire alarm at a bank. Using a fire axe he had no trouble getting into the building.

Nobody would ever work on the live server, right? Not intentionally, anyway


I once had the idea of selling digital speaker cable but I reasoned that no one would fall for that. Then I saw an advert for digital speaker cable.

The choice: Pay BT megabucks, or do something a bit illegal. OK, that’s no choice


Re: short cuts

Another true statement is: "You cannot communicate a ground reference faster than the speed of light."

If you are running signals a "long" distance you should also run the ground reference in the same direction in the same cable.

I used to run high-speed signals through ribbon cable grounding every other wire in the ribon. I used source termination (100 ohm resister in series with the source). The signal would divide in two at the transmitter end and send 1/2 the signal to the far end. Whereupon it was 100% reflected (making a full signal at the remote end). when the reflected signal got to the driver end it was 100% absorbed by the series resisters. This worked even though there might be multiple pulses in transit.

Linux lover consumed a quarter of the network


Re: Rule one...

At the college I was attending, the police came to the computer center and said they found someone with several 9-track tapes and an incoherent story about them -- something about research or something. So we mounted the tapes and didn't find anything suspicious. Then we had a hard time convincing the police that it was perfectly normal for a computer scientist to have a load of tapes with a very confused story about them.

Douglas Adams was right: Telephone sanitizers are terrible human beings


One day the college radio station went down. Sure enough a telephone repair man was in the basement disconnecting our wires to the transmitter. He was using an extremely old diagram and figured that the best way to proceed was to disconnect everything and then wire things up according to his outdated diagram. Physically pulling him away from the terminal block and reconnecting the stations wires fixed the problem.

Turning a computer off, then on again, never goes wrong. Right?


Re: PC Engineers...

We had a file server at Xerox that powered down when the building lost power. There was a good file scavenger program that could put all of the pieces together etc. Running it showed bad records in a spiral pattern across the disk. Evidently, the heads retracted while still writing!

(Backups restored everything.)


Re: Reminds me of an old (early '80s) AI koan ...

At the college I taught at we were studying permissions on files. Some student set the access pits to 000 on his user account and locked himself. Had to go to support to fix this.

Not really the students fault - he was just experimenting (as he probably should).

Nobody does DR tests to survive lightning striking twice


Re: Lightning always finds a way... of least resistance.

Lightning is a strange beast. A lot of it is RF. If you ground a lightning rod with a wire that makes a sharp turn, the lightning will go straight. The wire used to ground a lightning rod is a coarsely braided conductor more than an inch in diameter. All of the building gutters should be connected to the ground wires with a 1 inch wide copper strip. The actual ground to earth should be a 12 foot copper rod driven into the ground, preferably at three places around the house. The ground system should be wired to the electrical ground (that, by code, is a 6 foot galvanized pipe).

Remember, lightning rods attract lightning so you'd better be ready when lightning strikes.

It's 2023 and memory overwrite bugs are not just a thing, they're still number one


Re: GC - NO

Modern GCs handle circular structures just fine.


Re: > Cough, cough, use Rust.

Modern lisps are very efficient rivaling FORTRAN. A modern incremental GC is very fast and can be used for real-time programming. The old "stop the world" GCs are not used by modern GCs.


Re: Code cut...

What ever happened to LISP? It is fast, memory safe etc. and a pleasure to program in. A modern LISP has everything you need except acceptance. The newer programming languages haven't learned the lessons of LISP and reimplement everything in a buggy or limited way. The first LISP 1.5 is over 60 years old.

California man's business is frustrating telemarketing scammers with chatbots


If I answer, I always interrupt with, "How can I help you?" This blows them out of their script but if it is a friend etc. they just tell me how I can help them.

Doesn't work for the current crop of recorded telemarketer calls though.

Hacking a Foosball table scored an own goal for naughty engineers


At college there was an early dollar bill changer. I figured it was there to be tested by the students. So I took a dollar bill, tied a string around it, and placed it in the machine and slid in the slide. A fierce tug-of-war ensued resulting in a shredded dollar bill and a dollar's worth of change. I then carefully arranged the shreds of the bill on the slide. It took the pieces and delivered another dollar's worth of change.

A year latter I saw another dollar bill changer so I roughed up the leading edge of the bill (a technique I learned to cause jams in IBM card readers) and shoved it in. It took the bill but didn't give any change. I complained and the person in charge opened up the machine and saw that the bill had jammed in the mechanism but didn't fall to a micro switch that would release the change. So I guess they learned something.

Want to feel old? Ethernet just celebrated its 50th birthday


Re: Rings

The original ethernet was 3 MBits and used black RG11U foam 75 ohm impedance (with 50 ohm connectors!) cables with vampire taps. The speed of propagation was 66% of the speed of light. The design of the cable interface to the vampire taps was done by Tat Lam as the PARC people weren't really analog hardware experts. The collision detect would not work on very high-speed networks because of the speed of light/propagation. Tests showed 99% utilization with an offered load of 300%. We had multiple protocols running on the net: pup, leaf sequin, paulos, xns, ip, breath of life etc. with some other protocols for playing TREK or mazewars.

Some of these protocols also existed on the ARPANET

Eventually we got a 10 MBit cable with 50 ohm impedance.

TCP/IP didn't have a field to indicate other protocols so we used an illegal length to indicate the other protocols.

The original ALTO computers had a hard-wired 8-bit address which had to be changed when changing nets to avoid duplicating some other machine on the net. I think that the maximum number of nets was 255. It was hard tracking down another machine with the same address. The best strategy was to check who just received an ALTO.

Report reveals US Space Force unprepared to counter orbital threats


Re: Think Tanks found to leak; use New Never-Before-Seen Sealant for Instant Repair!

Actually, I think, "star wars" was a success. It didn't need to work but diverted a lot of Russian capital to counter it. It was an economic strategy.

Techie wasn't being paid, until he taught HR a lesson


Re: Unique keys

I once wrote a check to my daughter and forgot to sign it. I got calls but everyone said that the check was already processed. Eventually I got back the cancelled check with no signature.

Do banks really look at the signature?

Caltech claims to have beamed energy to Earth from satellite


Re: Misdirection

There was a road near a military base that used high-powered RADAR. The signal was strong enough to interfere with car's fuel injection electronics resulting in several stalled vehicles along this road. A business nearby with a pickup truck with a carburetor with no electronics made money towing these vehicles out of range of the RADAR.

Watchdog calls for automatic braking to be standard in cars


Re: Unintended consequences

Our car has automatic braking when on cruise control. It is not very smooth and sometimes when the car ahead changes out of my lane the system brakes anyway. If the car ahead slows down (smoothly) the system gets right behind the car and brakes suddenly.

Taking the car out of cruise control disables this feature.

It also beeps when backing up and a pedestrian walks around or a car sneaks up. This is good.

Mandating AEB might be good but the technology isn't quite there yet.

Is there anything tape can’t fix? This techie used it to defeat the Sun


Re: Sun outages

There was a case where a satellite receiving disk was aimed towards the sun and the sun rays were focused on the receiver which promptly melted. That's why they cover or paint the receiving disks.


Re: Ah, architects

I used to work in a completely dark office with just the computer screen for illumination. One night I was working, the trash collector came around and flipped on the lights and screamed when she saw me. Since I am not a tidy person there were papers everywhere. She asked about this and I said that there was some sort of an explosion and she went away completely satisfied.

We were scientists and we had a reputation to uphold.

Your security failure was so bad we have to close the company … NOT!


This was done at Dartmouth only they bricked over the door and painted the bricks to match.

Student requested access to research data. And waited. And waited. And then hacked to get root


Re: In Code We Trust

When I worked for Xerox I discovered a technique that would display anyone in the corporation's password in clear text. Even the CEO etc. A big hole in security. I sent the head of security his password with the code I used. It was for lazy PARC programmers that didn't like typing in their password all the time.

The head of Xerox security was asked if he changed his password (a long one etc.) and he said, "Why bother? Any new password would be just as vulnerable."

A year later this hack didn't work so I guess I had some effect in tightening security.

BOFH: We send a user to visit Kelvin – Keeper of the Batteries


Re: Nicknames

In the early days of the ARPANET routing all different kinds of packets was difficult. Someone came up with the routing protocol of "send to BRL" and let the guys at bell research deal with the packet.


Re: Keepers of...

At Xerox the computer center ordered 100 magnetic tapes. Purchasing, without telling any one, ordered a different brand to save $1 a reel. These tapes could not be rewound once without clogging the magnetic tape reader to such an extent that the tape actually stopped in the tape reader. It took several demonstrations to prove that the tapes were worthless.


Re: Keepers of...

There was someone in the computer room back in the '60s who would pick up any IBM card from the floor and put it with the new cards. He also insisted that the printer software be changed to not slew a page after printing the user account number. Multiple errors resulted from his (non blank) IBM cards and all of the users learned to slew a page before printing.

Inside FTX: Jokes about misplaced funds, diabolical IT, poor oversight, and worse



"$50m here, $50m there, pretty soon you're talking real money."

I think the real quote by Sam Rayburn (speaker of the house) was: "A billion hear, a billion there, and pretty soon you're talking real money."

Turing Award goes to Robert Metcalfe, co-inventor of the Ethernet


Re: Don't blame Metcalf for CAT 5 plug

I was at Xerox and used/maintained the 3 MBit ethernet cable. I never noticed much reflection from the tabs but did notice reflections from the cable connectors. The RG11U foam had a characteristic impedance of 75 ohms but the connectors were designed for a 50 ohm cable. The TDR I built could count connectors but barely nodiced the vampire taps. For a really long cable there were problems until I designed a bidirectional repeater which was placed in the middle of the long run.

Errors logged as 'nut loose on the keyboard' were – ahem – not a hardware problem


Re: Higgins

I have a granddaughter that can find unique key combinations, crash systems etc. She is 7 years old. If code passes the granddaughter test it is pretty solid.

IT phone home: How to run up a $20K bill in two days and get away with it by blaming Cisco


Re: The good old days :)

I just got a fiber for internet/phone. Now my dial [sic] telephone doesn't work.

The Stonehenge of PC design, Xerox Alto, appeared 50 years ago this month


Re: Three mouse buttons!

Every program had its own interpretation of the buttons. Sometimes in conjunction with the shift and control keys.

There was also a 5 key "chord" device.


Re: Smalltalk..the messaging killed it..

In my opinion, Smalltalk-76 was the best Smalltalk. Peter Deutsch (sp?) did Smalltalk-78 and had a JIT compiler in it. Both had a special character set. Smalltalk-80 used ASCII and lost something. I wrote a microcoded floating-point for Smalltalk that sped floating point up by at least a factor of three. I also microcoded some commonly used methods.

Smalltalk-76 also had the best debugger I have ever seen. An error (generally "message not understood" resulted in a stack window. When expanded there were six panes. The top two were the stack trace window and a code pane with the piece of the code causing the error highlighted. You could click on any other stack frame to see the code and highlighted piece.

The next two windows showed the "class" variables with a window that could execute code in the class environment.

The last two windows showed the local variables with a window that could execute code in the local environment.

There were many options for restarting, continuing etc.

The class browser was a pleasure to use for examining code or writing code. You could modify anything, including "system" code.

The system was persistent so all of your windows etc. were restored when restarted.

Don't worry, that system's not actually active – oh, wait …


At church we had a candle light vigil which set off the smoke alarm. Fire trucks and other excitement.