Random Ramblings to 28 August 2010

Carriage return
A typed character that commands the computer to move the cursor to the beginning of the line in a word processor. It is created using the Enter/Return key, which also sends another character that commands the computer to move the cursor to a new line. It is named after the lever on a typewriter, which performs both functions on a typewritten document.

Common good
In economics, a good that both is difficult for people to exclude from using (non-excludable) and suffers from reduced availability to others as it is used (rival). By its very nature, it is difficult for a business to sell goods of this type for profit, and so it often falls on the government to provide it. Examples of common goods include pastures (they are called 'the commons' in England), city streets and public benches.

Native command queuing (NCQ)
A technique used by hard disk drives (HDDs) to speed up access to data. It involves collecting a queue of data to read/write and reordering it to access the data in the minimal number of disk rotations. This minimises the amount of time the drive head spends flying between data locations (during which it is not reading or writing any data).

NCQ allows the right drive to complete this same queue in one less disk rotation than the left drive.

Nuclear fusion
A process by which the nuclei (cores) of two atoms are joined together (fused). This produces a new atom and, depending on the input atoms, may also release free subatomic particles. Also, depending on the energy needed to hold each atom's nucleus together (binding energy), either binding energy is freed or the energy used in fusing the atoms together is locked up in the new atom. Nuclear fusion may soon be used for generating power, where the binding energy of the new atom is less than the sum of that for the input atoms, resulting in a net release of energy.

The fusion of deuterium and tritium (both isotopes of hydrogen) into helium and a free neutron.

Reservation price
The threshold price used by a buyer or seller in deciding whether to take part in a trade. For a buyer, it is the highest price they are willing to pay, and for a seller, it is the lowest price they are willing to sell at. A trade will occur where the buyer's reservation price is more than or equal to the seller's reservation price, in which case they will negotiate a final price somewhere in between and both will be better off after the trade.

Sunburn
An area of skin damaged by long exposure to direct sunlight. The ultraviolet (UV) radiation in the sunlight kills skin cells in the upper layers, causing redness and soreness. There is also a chance that the UV will damage the DNA in the cells, potentially causing cancer. Using sunscreen (which filters out some UV before it reaches the skin) helps delay a sunburn.

Time dilation
The observation a moving object makes that non-moving objects encounter slower time. This arises because the speed of light is the same for all objects, regardless of speed. A beam of light as observed by a stationary object will travel the shortest possible distance, however, when the object starts moving, the light will also need to move along with the object, increasing the distance it travels. If it can only travel at a constant speed, it must take longer to get to its destination, causing time to slow down.