19 September 2017

Halt and Catch Fire

Halt and Catch Fire is an American drama television series about a fictionalized version of the history of the personal computer revolution of the 1980s and then the growth of the World Wide Web in the early 1990s.

The show's title refers to a computer machine code instruction abbreviated as HCF. Halt and Catch Fire refers to a computer machine code instruction that causes the computer's central processing unit (CPU) to cease any meaningful operation to the point of requiring a restart of the computer.

Originally it referred to a fictitious instruction in IBM System/360 computers. Later, the joke became real when developers actually wrote such code.

Usually, when a computer hits a bug in the code it probably can still recover, but an HCF instruction is one where there is no way for the system to recover without a restart. It halts the computer, but the "catch fire" part is not literal. There is no computer bursting into flames. The exaggeration was that the circuits would be switching so fast that they would overheat and burn.

15 September 2017

Measuring Energy

One of the biggest honors a scientist can receive is to have his or her name attached to their invention or discovery. These new words are known as eponyms, and here are some eponyms we have for the measurement of energy.

James Prescott Joule (1818–1889) gave us the joule, a unit that measures work, or energy (a force acting over distance. He was a British physicist who established that all forms of energy are equivalent.

Joule also developed thermodynamics, along with Lord Kelvin who is better known because absolute temperatures are stated in units of kelvin in his honor. While the existence of a lower limit to temperature (absolute zero) was known prior to his work, Lord Kelvin is widely known for determining its correct value as approximately −273.15 degree Celsius or −459.67 degree Fahrenheit.

Our common energy measurement of volts comes from Alessandro Volta (1745–1827). This unit measures differences in electrical potential. The Italian physicist Volta also discovered methane and  used his tongue to detect electricity and invented the first electric battery.

Another major electrical unit, the current-measuring ampere, takes its name from French physicist André-Marie Ampère (1775–1836) who was one of the main founders of the science of electromagnetism, which he called “electrodynamics.”

11 September 2017


U2 is a rock band from Dublin, Ireland that consists of Bono (vocals and guitar), The Edge (guitar, keyboards and vocals), Adam Clayton (bass guitar), and Larry Mullen, Jr. (drums and percussion). They are one of the top rock acts in the world.

U2's early sound was post-punk but evolved and now includes influences from a variety of genres. A key part of their sound comes from The Edge's guitar playing and Bono's distinctive vocals.

Their songs' lyrics are frequently spiritual imagery, personal themes and also socio-political concerns. Bono is well known for his support of many causes.

The band formed in Dublin in 1976 when 14 year old Larry Mullen, Jr. put a sign on his school bulletin board looking for musicians for a new band.

The resulting group was called The Larry Mullen Band "for about ten minutes" but the addition of Bono meant a new center.

This band was Mullen on drums, Paul Hewson (Bono) on vocals, David Evans (The Edge) and also his older brother Dik Evans on guitar, Adam Clayton, on bass guitar. They used the name "Feedback" for it's guitar amplification reference. They were basically, like most young bands, a cover band and showed the influence of punk bands such as The Jam, The Clash, and The Sex Pistols.

In March 1977, the band changed their name to "The Hype". The older Dik Evans walked away from the band (literally, during a gig) the following year. The remaining four band members started using more original material and were billed as "U2".

Supposedly, Steve Averill, a punk rock musician and family friend of Clayton's, had suggested six potential names from which the band chose "U2."

There is no solidly validated reason for the name choice other than perhaps its brevity, intentional ambiguity and opportunities for interpretations.

I couldn't find any further explanation on U2's official website or in the book, U2 by U2.

But there are many references that might have influenced the choice. Best known to Americans is that a U2 is a type of spy plane used by the United States in the 1960's which was made famous when a 1960 international incident. A U.S. Lockheed U-2 plane over the Soviet Union was shot down over Russia and resulted in the pilot being taken as a prisoner during the Cold War.

A U2 is also a dry-cell battery type now known in the U.S. as a D battery.

How to Dismantle an Atomic BombA number of European railway systems have a U2 as part of their designations.

U2 can also be seen as being a version of "you too" referring to the audience and its role in the band's musical experience

I have also seen a reference to a U2 being a government form used in Ireland - but that seems to more likely be the origin, as we have explicated, for UB40.