Friday, June 29, 2007


A superscalar CPU architecture implements a form of parallelism called Instruction-level parallelism within a solitary processor. It thereby allows faster CPU throughput than would otherwise be possible at the same clock rate. A superscalar architecture executes more than one instruction during a single pipeline stage by pre-fetching several instructions and at the same time dispatching them to redundant functional units on the processor.


Seymour Cray's CDC 6600 from 1965 is often mentioned as the first superscalar plan. The Intel i960CA and the AMD 29000-series 29050 microprocessors were the first commercial single-chip superscalar microprocessors. RISC CPUs like these brought the superscalar idea to micro computers because the RISC design results in a simple core, allowing straightforward instruction send off and the inclusion of multiple functional units on a single CPU in the inhibited design rules of the time. This was the reason that RISC designs were faster than CISC designs through the 1980s and into the 1990s.

Sunday, June 24, 2007


Swans are large water birds of the family Anatidae, which also includes geese and ducks. Swans are grouped with the intimately related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometimes, they are considered a distinct subfamily, Cygninae.

Swans typically mate for life, though "divorce" does sometimes occur, mainly following nesting failure. The number of eggs in each clutch is between 3–8.
The word is derived from Old English swan, akin to German Schwan, in turn derived from Indo-European root *swen (to sound, to sing), whence Latin derives sonus (sound). Young swans are known as cygnets, from the Latin word for swan, cygnus. An adult male is a cob, from Middle English cobbe; an adult female is a pen .

Tuesday, June 19, 2007


Lopping, also known as tree lopping and topping, is the practice of cutting trunks and branches of a tree in an effort to contain the tree's size or shape. Lopping is differentiated from other styles of pruning by where the cuts are made. When a tree is lopped, the cuts are made internodally, or not at branch unions and collars at the correct angles, leaving a piece of protruding timber that is called a stub.
Lopping in many cases is careful an inappropriate pruning method for amenity trees. The lopped stubs may regrow adventitious epicormic shoots which are bonded only to the bark. These epicormic shoots can grow dynamically and, unless regularly pruned off, may outgrow the original height and spread of the tree. Further, the ends of the lopped stubs are exposed to pathogens which may enter and infect the tree.
In orchards, fruit trees are often lopped to encourage regrowth and to keep a smaller tree for ease of picking fruit. The pruning regime in orchards is more intended and the productivity of each tree is an important factor. In an orchard, though, the natural longevity of a tree is often compromised in favor of its output in fruiting. Orchard trees are also carefully monitored and treated with fungicides and insecticides to minimise losses.

Tuesday, June 12, 2007


Genetics is the science of heredity and variation in living organisms.Knowledge that desired characteristics were present at birth has been implicitly used since prehistoric times for improving crop plants and animals through selective breeding. However, the modern science of genetics, which seeks to understand the mechanisms of inheritance, only began with the work of Gregor Mendel in the mid-1800s.
Mendel observed that inheritance is basically a discrete process with specific traits that are inherited in an independant manner. These basic units of inheritance is now known as "genes". In the cells of organisms, genes exist actually in the structure of the molecule DNA and the information genes contain is used to create and control the components of cells. Although genetics plays a large role in determining the appearance and behavior of organisms, it is the interaction of genetics with the environment an organism experiences that determines the ultimate outcome. For example, while genes play a role in determining a person's height, the nutrition and health that person experiences in childhood also have a large effect.

Thursday, June 07, 2007

Water abstraction

Water abstraction, or water extraction, is the process of taking water from any source, either temporarily or permanently. Most water is used for irrigation or treatment to produce drinking water.Depending on the environmental legislation in the relevant country, controls may be located on abstraction to limit the amount of water that can be removed. Over abstraction can lead to rivers drying up or the level of groundwater aquifers reducing unacceptably.The science of hydrogeology is used to assess safe abstraction levels.

Sunday, June 03, 2007

Peripheral Component Interconnect

The Peripheral Component Interconnect or PCI Standard specifies a computer bus for attaching peripheral devices to a computer motherboard. These devices can take any one of the following forms:

An integrated circuit fitted onto the motherboard itself, called a planar device in the PCI specification. The PCI bus is common in modern PCs, where it has displaced ISA and VESA Local Bus as the standard expansion bus, but it also appears in many other computer types. The bus will eventually be succeeded by PCI Express, which is standard in most new computers, and other technologies.

The PCI specification covers the physical size of the bus (including wire spacing), electrical characteristics, bus timing, and protocols. The specification can be purchased from the PCI Special Interest Group (PCISIG).