* Posts by swm

213 posts • joined 6 Jun 2015

Page:

Techie in need of a doorstop picks up 'chunk of metal' – only to find out it's rather pricey

swm

Re: Watch out for geological samples

In college my radium wrist watch was a stronger emitter was stronger than any sample they let the undergraduates play with. None of the permitted sources would saturate a geiger counter but my watch demonstrated the effect perfectly. After the at people started to edge away from me for some reason.

swm

My son worked at AMD as a coop. He was nonchalantly carrying a "boat" of 24 silicon wafers from place to place when a supervisor pointed out to him that he was carrying about a quarter of a million dollars worth of product.

Help us sniff out 50 neutron star collisions so we can calculate universe expansion, cosmoboffins plead

swm

Re: How small can you make a black hole?

Actually an evaporating black hole should release quite a lot of energy in its dying moments. The amount released in the last second is pretty constant so might serve as a "standard candle" although I don't believe any have been observed yet.

Crash, bang, wallop: What a power-down. But what hit the kill switch?

swm

Legitimate use of EPO buttons

In the computer center the chief operator was an ex marine gunnery sergeant. In New Hampshire we always complained about the low humidity. The HVAC folks said they could fix this. The next moment the machine room started filling up from the bottom with fog. The operator calmly went to the EPO button and pressed it. It worked and he probably saved a lot of spinning rust.

When designing the operating system I had to debug the power off shutdown fault (meaning that there was 160 usec before CPU power dropped). There was just this time to save all of the essential state in core (yes, real core). So I sat powering down and up the main cpu - a huge monster - to test this. The field engineers were not happy as they said that the CPU wasn't designed for repeated power cycling but never had any problems.

So there are some legitimate uses for these buttons.

Earth's noggin took quite a clockin' back in the day: Now a second meteorite crater spotted under Greenland ice

swm

The cratered Earth

If two big craters are known in Greenland how many craters have yet to be discovered in the rest of the world?

Reliable system was so reliable, no one noticed its licence had expired... until it was too late

swm

Re: There were ways around it

My grandfather, who lived to almost 102, had an argument with his life insurance company as they wanted him to cash in his policy and, for tax reasons, he didn't want to. Turns out that the problem was that the age field in their database system only allocated 2 digits for age.

Techie finds himself telling caller there is no safe depth of water for operating computers

swm

Re: Danger! High Voltage!

Where I worked a large high voltage transformer that powered the building blew up early one morning. This was right near the guard station at the entrance of the building. On questioning the guard said there was a hell of a noise but didn't think to report it!

When the replacement transformer was installed a workman attached the wires live to the new transformer. Two other workmen held 2x4s which the workman reached over to do the final connection. They braced themselves - ready to pull hard. Their job was to pull the first workman off of the wires if anything went wrong. All three workmen took their job very seriously.

This is a job I would never want.

'Numpty new boy' lets the boss take fall for mailbox obliteration

swm

Re: 100% honesty 90% of the time

When I was the chief architect of the second Dartmouth Time Sharing system I had an agreement with the operators to tell me exactly what they did when they screwed up as this information was invaluable to recovering from their mistake. Sometimes it was a system problem inadequately presented to the operator and other times it was a genuine operator error. I made sure that none of the operators got in trouble and recovery was made much simpler.

Ooh, my machine is SO much faster than yours... Oh, wait, that might be a bit of a problem...

swm

Re: A little different...

What about computed come from statements?

swm

Re: Well that was an invisible problem

When the ethernet was invented at Xerox they had about 100 ALTO machines on one RG11U foam 3MBit coax. They set up a test by having all of the machines transfer data up to 9000% of the cable's capacity. Things slowed down (of course) but there were few lost packets because of the collision detect and retransmit algorithms in the machines. ALTOs were not capable of sending or receiving back-to-back packets so would miss consecutive back-to-back packets sent to the same machine.

Another test revelled that about .01% of the packets were received corrupted and this was traced to a synchronizer timing error in the ethernet tranceivers. When this was corrected the error rate went down to less than 1 in a million.

Sounds like a router/switch problem.

Are you sure your disc drive has stopped rotating, or are you just ignoring the messages?

swm

Re: Find the "A" key

At college they bricked up the doorway to a student's room and painted over the wall so that there appeared that no door was ever there.

swm

Re: I can believe it!

At Dartmouth we had a room full of a huge mainframe computer. The machine room was alwasy open for students to wander in and out. One day, the insurance company insisted that all of the windows looking into the machine room be covered with bullet proof lexan. The doors to the machine room were still left open for the students to freely wander in and out though.

The Large Hadron Collider is small beer. Give us billions more for bigger kit, say boffins

swm

There is a lot we don't know

It is known that the standard model is not completely correct. Also, a quantum theory of general relativity is not renormalizable using standard techniques. Also, the properties of the Higgs boson are poorly known. Almost any symmetry breaking of U(1) x SU(2) results in the standard model. There are about a dozen constants in the standard model that are put in "by hand" whose values are not given by the standard model. The cause for three generations of particles is unknown.

It is interesting that the four forces all seem to be gauge forces (except the gauge group of gravity is not compact - causing technical difficulties).

So, no, we do not know the underlying laws of physics - whether a bigger collider will answer these questions is unknown. Perhaps studying neutrinos would yield more results.

Before dipping a toe in the new ThinkPad high-end, make sure your desk is compatible

swm

Two 49" screens for surround video

I want two of them. I would stack them as in the picture. You can't have enough screen real estate.

You were told to clean up our systems, not delete 8,000 crucial files

swm

Re: A "proper" OS...

The Dartmouth time sharing system II had "catalogued" files (and directories) and "scratch" files (and directories). The former were in the directory hierarchy while the latter only lived while the process was active. You could move a file from one state to the other. Once we wanted to give a copy of the system to someone so we "uncatalogued" the top of the student file hierarchy and ran a logical dump of the root of the file system. When we were done, just for fun, we dropped the student file hierarchy and watched the system cleanup and reclaim space. After an hour we killed the system and rebooted from backups.

swm

Re: xfer

I have files going back more than 30 years. Some of them are still useful (for some definition of "useful").

Fake 'U's! Phishing creeps use homebrew fonts as message ciphers to evade filters

swm

Re: People still falling for the fake email.

The head of one of the major security vendors gave a talk at our college and said that his wife had been banned from her provider because she clicked on any "click me" or equivalent link and downloaded lots of bad stuff.

In response to a direct question as to which antivirus tools he used he said he didn't use any - he was just careful!

New side-channel leak: Boffins bash operating system page caches until they spill secrets

swm

When I wrote the executive for the Dartmouth time sharing system (Mark II) I had a file in the top-level directory that mapped to core (yes, real core). It was protected against read and write access. Someone thought it harmless to allow read access. Someone else wrote a program that attempted to open a file with the wrong password, scan all of core for the file name, and look nearby for the password.

Another hack on the TENEX operating system was to try to open up a file but put the password straddling a page boundary. If the first part of the password was correct you got a page fault when the OS accessed the remainder of the password else no page fault. By trying all possible characters you could get one character of the password. Shift the password and repeat.

You can't allow any access to information about the executive going about its work - no metering, accurate timers, number of page faults etc.

I'm just not sure the computer works here – the energy is all wrong

swm

Re: Mythbusters

The real reason for no cell phones on aircraft is that, in flight, they hit too many cell towers and use up too many channels. The rule is from the FCC not the airlines.

swm

Re: Similar story

I heard about a tow truck company with old-fashioned carburetor that had a business of towing cars with electronic ignitions out of range of a military radar set.

New Horizons probe reveals Ultima Thule is huge, spinning... chicken drumstick?

swm

Ultima Thule

Nicknamed "Ultima Thule" (meaning "beyond the known world")

One of my Latin dictionaries defines "thule" as "island in the extreme North (perhaps Shetland". Another Latin dictionary says, "island located in the extreme North, perhaps Iceland or part of Scandinavia". Seems appropriate.

It's 2019, the year Blade Runner takes place: I can has flying cars?

swm

Re: I have written to my bank

How about s/he/it?

Bored IT manager automates Millennium Eve checks to ditch snoozing for boozing

swm

I believe that Thomas Edison automated a telegraph key with a mechanical clock to prove that he was awake on long nights. Eventually he was caught when he didn't reply to messages and someone came to check.

50 years ago: NASA blasts off the first humans to experience a lunar close encounter

swm

Re: Remember (AGC computer)

The AGC had an interesting instruction "INX"? (index) which added data fetched from its effective address to the next instruction. This allowed any location in memory to be used as an index register. You could also add to the 3-bit op code. If the addition overflowed, the overflow bit became another opcode bit. I have never heard of any other computer with a similar scheme.

Heard the one where the boss calls in an Oracle consultant who couldn't fix the database?

swm

I once designed a board to drive a laser printer. The commands were sent via a UART and status returned via the same UART. The UART was driven by microcode on a Xerox ALTO computer. The test group claimed I was sending an extra garbage byte at the end of printing. So I added microcode to dump into memory a trace of all characters sent or received. No garbage character?! I watched their test setup and noticed that the garbage character was being sent when my program terminated. Turns out that resetting the UART would send a garbage character. Sending a character without a start bit before resetting the UART solved the problem.

I was in research and the testers were in development but I'd learned to listen carefully to developers and people on the production line - they might know something you don't.

Staff sacked after security sees 'suspect surfer' script of shame

swm

Re: Access Denied

How about xxx.lanl.gov?

Your mates vape. Your boss quit smoking. You promised to quit in 2019. But how will Big Tobacco give it up?

swm

Re: New markets

When I went to college the tobacco companies sent a representative to hand out free cigarettes in the lunch line.

College PRIMOS prankster wreaks havoc with sysadmin manuals

swm

Re: School computer rooms (keys)

I was in the habit of making grand master keys at college so they just gave me a master key to the computing center. Spoiled some of the fun.

swm

Re: BBC Micros at college

At Xerox PARC when they brought up a new TENEX machine they had to get all of the user passwords for the new machine. Rather than bother all of the users they ran a net sniffer for a week and picked up most of the passwords which they then loaded into the new machine.

In those days passwords were mainly to prevent stupid mistakes rather than for security.

I once mailed the head of computer security his password but that is another story.

Long before TCP/IP etc.

Identity stolen because of the Marriott breach? Come and claim your new passport

swm

Re: And one requirement to use this is

I just received a well-written email from starwoodhotels@email-marriott.com with many links to www.annualcreditreport.com, www.equifax.com, www.ct.gov/ag etc. Curiously all links point to the same address. Checking whois it seems that the address of email-marriott.com is owned by Marriott so maybe the security breach is not over. Pinging email-marriott.com failed. I did not try going to the nice link they provided.

Take my advice and stop using Rubik's Cubes to prove your intelligence

swm

Re: 1970s?

That's how I would solve the "Rubik's" cube. People who knew me would assume I would "solve" the cube but age and treachery beats youth and skill. I taught my son the disassembly technique and he disrupted an entire math class demonstrating.

Support whizz 'fixes' screeching laptop with a single click... by closing 'malware-y' browser tab

swm

Re: Dim advice by the dashboard lights

My son had, as his first car, an old junker. He called me up one day and said his car wouldn't work. "Is there gas in the gas tank?" I asked. "Oh, I'm sure there is," he replied. Turns out that he and his sister shared this car and he was extremely parsimonious about putting gas in the tank. Putting gas in the car magically made the car work again.

swm

Re: For old times' sake

"And better manuals"

The computer manuals from the '60s were great. They actually told how things worked. The early IBM manuals and, of course, the LGP-30 manual were all you needed to start using the computer. Nowadays manuals tell you how to do something but refuse to give you a model of what's happening. So you have to reverse engineer everything to do something slightly different.

GTA gamer cuffed, charged after PS4 live mic allegedly overheard him raping teen girl

swm

What about successful suicides?

Sacked NCC Group grad trainee emailed 300 coworkers about Kali Linux VM 'playing up'

swm

Re: I know it's unlikely

I once hired a co-op and one day she came to me and said that there was something wrong with her X-terminal. I went and looked and saw a small rectangle in the upper left corner of the screen. Every 30 seconds a flying saucer would be launched from this box and chase down the cursor. When it caught the cursor, it would drag the cursor back to its base. You could evade the flying saucer because it was slow but until it succeeded in dragging the cursor back to its base the flying saucer continued to harass you.

I laughed and looked around and spotted some smirking co-ops - I told them to to turn off their fun prank. The X protocols weren't very secure in those days.

NASA's Mars probe InSight really has Mars in sight: It beams back first pic after touchdown

swm
Pint

JPL is absolutely amazing. Both the software and hardware have to work to make a successful landing.

Consultant misreads advice, ends up on a 200km journey to the Exchange expert

swm

Re: Spoilers in Tech Docs!

"Just dial 555-1212"

Has anyone seen a dial telephone recently? I have an old dial telephone and my granddaughter (13 years old) struggled to make a call on it (as did a full professor at my college years ago). My 3-year old granddaughter loves the dial phone to play with.

swm

Re: Spoilers in Tech Docs!

"When visiting friends, do you click the doorbell or do you press it?"

No, I ring the doorbell.

Big data at sea: How the Royal Navy charts the world's oceans

swm
Headmaster

Re: Depends on what you want to do.

"fix by it's self"

it's = it is

its = possessive pronoun

Pasta-covered cat leads to kid night operator taking apart the mainframe

swm

Re: RE: Dried Pasta & Stubborn, Unmoving Cats...

"You can't train a cat, all you can do is make it more sneaky about doing whatever it wants to do."

I had a friend who had trained his cat to roll over on command. It was quite amusing to watch.

Holy moley! The amp, kelvin and kilogram will never be the same again

swm

Re: Scale

The speed of light is about one foot per nanosecond.

swm

The meter bars were slowly warping which is why the meter is now defined in terms of physical experiments and not physical artifacts.

Bright spark dev irons out light interference

swm

Re: It's called a choke.

When I worked in research I would use ribbon cable to send high-speed signals from one side of the lab to the other. Never had a problem until I interfaced to a Xerox machine. The interface didn't seem to work but on closer inspection I found it wasn't the 50 foot ribbon cable but the connection from one card to the adjacent card in the Xerox machine. Using a large voltage swing CMOS driver on the card driving the other card fixed the problem. Xerox machines were electrically noisy with an inadequate grounding scheme.

TTL never liked driving long wires. I always used series termination at the driving end.

Another Meltdown, Spectre security scare: Data-leaking holes riddle Intel, AMD, Arm chips

swm

Speed vs. Security

The chips are doing exactly what they were supposed to do. Namely, burn for speed. If you want real security you have to physically separate different classes of users and not run them on the same chip/computer/memory system etc. My reaction to all of this is I want my computer to be fast and will secure it at the edge.

Irony meters explode as WordPress GDPR tool hacked, cell network hack shenanigans, crypto-backdoors, etc...

swm

Re: The downside to unregulated currency

"there are no mechanisms in place to get it back"

The same is true of cash.

How one programmer's efforts to stop checking in buggy code changed the DevOps world

swm

Re: Jenkins?

The standard C or C++ makes an exception for the main procedure - it doesn't have to have a return statement.

Can your rival fix it as fast? turns out to be ten-million-dollar question for plucky support guy

swm

Re: Not just assembly.

This used to be a technique to get more memory by using constants as variables.

On the IBM 1620 FORTRAN copying from an uninitialized variable could cause memory to be cleared as the uninitialized variable had no "flag" indicating "end of number".

On the SIGMA 7 you could intersperse machine instructions in your FORTRAN code. I once wondered why why a SW instruction (Store Word) wasn't changing memory until I realized the opcode was STW.

Finding your own bugs is hard.

Astroboffins spot one of the oldest, coolest stars in the universe lurking in the Milky Way

swm

Re: up to 1,000 kelvin (726.85 degrees Celsius).

As I understand it the normal body temperature of 98.6 degrees came from converting 37 degrees Celsius to Fahrenheit. The original 37 degrees was an average body temperature of several individuals rounded to the nearest degree Celsius so had ~ 2 significant digits. The 98.6 is bogus accuracy and, in fact, is a little high.

DBA drifts into legend after inventive server convo leaves colleagues fearing for their lives

swm

Re: But can I get F1 on my BT account

"quite serious operators who had undergone a humour bypass"

At Dartmouth College we had an ex marine gunnery sergeant as a computer operator. The business manager of the center would sneak in and deposit a large cardboard box labelled "bomb" on all sides on the console typewriter. His reaction was to drop kick it out of the room.

Another story I heard was at MIT they had a "fire hose" drum used for swapping. One day a plasterer caused the filters to clog up. "No problem," said the field engineer, pulled out the clogged filters and before he could replace them the drum inhaled enough plaster to totally crash every head on the device.

Clunk, bang, rattle: Is that a ghost inside your machine?

swm

Re: RFI ghosts

When I was in college writing the executive for the Dartmouth time sharing system we had delivered an RCA RACE unit for storage. I was told to hook it into the system as a low-priority task when I had time. So I did but whenever I configured the unit into the system (via a configuration punched card) the system would always give an immediate "transfer timing error". The field engineers would run their diagnostics at night and never saw that fault. Eventually we decided that we should get together and figure out what was going on. I knew exactly which card in the card deck (the configuration card) the system would fail so I didn't bother to load the rest of the cards after it. When the system read the configuration card everything worked perfectly and the system asked for the remainder of the card deck!?

I was about to repeat the experiment with the complete deck when the field engineer (who was very good) stopped me and reached over to the card reader and pulled back the hopper and said, " do you hear that whine?" He then ran his diagnostics with the card reader on and pulled back the hopper on the card reader when the diagnostics were running. Instant transfer timing errors.

It turned out that the field engineers ran their diagnostics from tape with the card reader off as it was too noisy. Investigation showed that the speed of a brush vacuum motor was controlled by SCRs and someone had put capacitors across the motor windings to "eliminate" noise. When the SCR fired it put the capacitor across the utility supply line causing 70 volt spikes. This got into the peripheral wires and caused the errors.

We quietly removed the capacitors and things worked better. The RACE unit never did work reliably - shooting out springs and crumpled cards but at least we solved one problem.

Page:

Biting the hand that feeds IT © 1998–2019