Posts by Alan J. Wylie

Apposite quote

Critical systems do not fail because a person makes a mistake, but because insufficient controls fail to prevent the mistake.

-- Dr. Johannes Ullrich

in a recent SANS NewsBites e-mail, on the subject of the NOTAM outage

US Survey Foot

At least, as of three weeks ago, the US has deprecated the Survey Foot. Before 1959, the US defined the foot as 0.304 metres, rather than the exact value of 0.3048.

The 1959 redefinition of the foot was legally binding and intended for the entire United States. But a single exception temporarily allowed continued use of the previous definition of the foot, exclusively for geodetic surveying. To distinguish between these two versions of the foot, the new one was named the “international foot” and the old one the “U.S. survey foot.” It was furthermore mandated that the U.S. survey foot be replaced by the international foot upon readjustment of the geodetic control networks of the United States. Although such a readjustment was completed in 1986, use of the U.S. survey foot persisted. This situation has led to confusion and errors that continue to this day, and it is at odds with the intent of uniform standards.

The software on a 747 is updated from floppy disc.

My comment yesterday in the El Reg article Longstanding bug in Linux kernel floppy handling fixed linking to an article from 2020

Boeing use(d) them

El Reg article from 2020: Boeing 747s receive critical software updates over 3.5" floppy disks, though, co-incidentally, the last 747 rolled off the production line today.

20 year old HP LaserJet

I bought a HP LaserJet 1200 in January 2002 (£235.45). It's still going strong, with just one replacement toner cartridge. I turn it off when not in use. The energy I use is miniscule compared to that needed to manufacture a new printer.

I don't use it very often, but I've just printed out 97 caving rigging guides from the CNCC web site. It worked perfectly. No nozzles to clog. No yellow tracking dots.

Air France Flight 447

Another example of a tragedy resulting from the interaction of automated systems and humans.

Wikipedia article

The Airbus A330 is "fly by wire" and has several flight control modes: "Normal Law" and two "Alternate Laws". These map the movement of the yoke or joystick into movement of the control surfaces.

A pitot tube was probably blocked with ice, returned the wrong air speed. The autopilot disconnected and transitioned from "normal law" to "alternate law 2". A human pilot took the controls, and to cut a long story short pulled back on the stick, causing the aircraft to climb rapidly, then stall.

The "ECB penguin"

In the case of an image where pixels of the same color get represented by the same plaintext, the corresponding ciphertext is also the same for like pixels, which makes the image visible through the ciphertext.

The canonical example can be found here: https://words.filippo.io/the-ecb-penguin/

Day Old Bread

Ah, memories of the now defunct "Day Old Bread" Realtime blocklist: a DNS lookup returned the status of domains registered in the past 5 days

Archive.org mirror

An old patent: "Device for controlling a light beam"

That reminds me of this patent from 1968.

Otto Frisch founded the first company I worked for after leaving University.

Notes on unsafe standard library functions

gcc has the #pragma poison directive, which causes it to emit a hard error if it encounters a listed function: example list

And some of the replacements aren't 100% safe either: a comment from Linus the day before yesterday on "a very subtle difference between strlcpy and strscpy".

Arc flash?

Perhaps an Arc flash ?

The potash mine in Cleveland was fined £3.6million recently after such an accident

Update: arc flash confirmed

From "The IT crowd"

You wouldn't steal a handbag

Obligatory XKCD

Compiling

3.0.x is still "Masked" on Gentoo

Meanwhile, Linux distributions like Gentoo have not yet rolled out OpenSSL 3.0.4 as a result of this bug and a test build failure bug. So they include OpenSSL 3.0.3, with its command injection flaw.

The default build on Gentoo still uses 1.1.1o, to enable 3.0.x you would need to explicitly edit a configuration file to "unmask" the version.

There are still many packages, e.g. versions of Ruby and PHP which won't build against 3.0.x

A similar story involving core store

A previous post of mine:

"You mean that the top secret contents of memory don't get lost when we power off?"

RISCiX

Me again, after posting yesterday about 1st Word+ on the Archimedes.

UNIX did come to the Archimedes

On the 8th March, 1988, still working for GST in Cambridge, I worked on a "UNIX Kernel Validation Suite" to test the port of BSD 4.2 (and shortly afterwards, 4.3) to the Archimedes

Some history here: Chris's Acorns: RISC iX

It exercised all the (2) system calls with expected arguments to check correct functionality and invalid arguments to check error returns.

I've got lots of scribbles in my daybook on the design and implementation, paper is definitely more persistent that bits on Winchesters. I wonder whether a historian might be interested in some of my jottings?

spread spectrum hopping

Courtesy of Hedy Lamarr

I'm triple vaccinated, however I'm currently testing positive for Covid-19 (and feeling distinctly under the weather). The only time I cough is when I'm very occasionally bringing up phlegm from my lungs. I certainly don't have the "dry" cough which has been one of the symptoms.

Rock Linux

the first rolling-release distro – that was arguably Gentoo, founded in 2000

The first stable release of Rock Linux was August 1999. Not to be confused with Rocky Linux. Like Gentoo, you compiled everything yourself.

Archived "news" page

Wikipedia article on a fork of Rock

The answer's simple. A man with a red flag walking in front of the scooter.

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Spoiler for those who don't spot the reference

Glitter nail varnish

Glitter nail varnish was suggested to be used for this back in 2013. It has the additional advantage that it can be used to seal a screw-head

Wired article

Thwarting Evil Maid Attacks

Mentioned in the video at about 51:50

Obligatory XKCD

Devotion to Duty

VMS got it right

VMS (since 1977) has stored time as 100ns clock ticks since 17 November 1858 (the start of the Reduced Julian Day (an astronomical timescale, the "reduced" variant was introduced by the Smithsonian Astrophysical Observatory in 1957 to record the orbit of Sputnik). It will run out of bits in the year 31,086.

The VLS space is sprayed down with water

Fresh or sea water?