Monday, January 28, 2008


Minicomputer is a mostly outmoded term for a class of multi-user computers which generate the middle range of the computing spectrum, in between the largest multi-user systems (traditionally, mainframe computers) and the smallest single-user systems (microcomputers or personal computers). Formerly this class created a distinct group with its own hardware and operating systems notably having smaller address space (notice the cited numbers of bits in a data word, ranging from 8 to 24 bits commonly around 16-bits). While the distinction between mainframe computers and smaller computers residue fairly clear, contemporary middle-range computers are not well differentiated from personal computers, being typically just a more powerful but still compatible version of a personal computer. More modern conditions for such machines consist of midrange systems (common in IBM parlance), workstations (common in Sun Microsystems and general UNIX/Linux parlance), and servers.

Sunday, January 20, 2008


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 (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

Advances in one either resulted beginning or precipitated advances in the other. Originally, bullets were surrounding metallic or stone balls placed in front of an explosive charge of gun powder at the end of a closed tube. As firearms became more scientifically advanced, from 1500 to 1800, bullets changed very little. They remained uncomplicated round lead balls, called rounds, differing only in their diameter.

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.