Minicomputer
Monday, January 28, 2008
Sunday, January 20, 2008
Microcomputer
A microcomputer is mostly often taken to mean a computer with a microprocessor (µP) as its CPU. Another common characteristic of these computers is that they take up physically small amounts of space. Desktop computers, video game consoles, laptop computers, tablet PCs, and a lot of handheld strategy may all be considered examples of microcomputers. Most microcomputers serve only a particular user at a time, but some, in the form of PCs and workstations running e.g. a UNIX(-like) operating system, may cater to a number of users concurrently. The µP does the greater part of the job of calculating on and manipulating data that all computers do.
Monday, January 07, 2008
Mainframes
Mainframes (often colloquially referred to as big iron) are enormous and expensive computers used mostly by government institutions and large companies for mission critical applications, usually bulk data processing such as censuses, industry/consumer statistics, ERP, and financial transaction processing.
The term originated during the early 1970s with the introduction of lesser, fewer complex computers such as the DEC PDP-8 and PDP-11 series, which became known as minicomputers or in a minute minis. The industry/users then coined the term "mainframe" to describe bigger, earlier types (previously known simply as "computers").
Tuesday, January 01, 2008
The first bullets
The development of the hand culverin and matchlock arquebus brought regarding the use of cast lead balls as projectiles. "Bullet" is consequential from the French word "boulette" which roughly means "little ball". The original musket bullet was a spherical lead ball two sizes slighter than the bore, wrapped in a loosely-fitted paper patch which served to hold the bullet in the barrel firmly upon the powder. (Bullets that were not firmly upon the concentrate upon firing risked causing the barrel to explode, with the condition known as a "short start".) The loading of muskets was, therefore, easy with the old smooth-bore Brown Bess and comparable military muskets. The original muzzle-loading rifle, on the other hand, with a more intimately fitting ball to take the rifling grooves, was loaded with difficulty, particularly when the bore of the barrel was dirty from previous firings ("fouled"). For this reason, early rifles were not generally used for military purposes. Early rifle bullets necessary cloth patches to grip the rifling grooves, and to hold the bullet securely against the powder.
The first half of the nineteenth century saw a different change in the shape and function of the bullet. In 1826, Delirque, a French infantry officer, imaginary a breech with abrupt shoulders on which a spherical bullet was rammed down until it caught the rifling grooves.