How Does a Computer Know ?
Have you ever wondered just how the computer knows what to do when it first boots up? Have you ever wondered what exactly it does when it starts up? Well, for the curious minded, I will give you brief synopsis of how your computer works.
But first a little background information. Do you know how long the computer has been around? Of all the pre-20th century thinkers and tinkerers who added something to the development of computing, the one who came the closest to actually inventing a computer, in the modern sense, was an Englishman named Charles Babbage. Born into a wealthy Devonshire family in 1791, Babbage earned fame for both the keenness of his mind and the crankiness of his personality. For 13 years this eccentric genius occupied the same Cambridge chair of Mathematics once held by Sir Isaac Newton. Yet in all that time he never lived at the University or delivered a single lecture there.
In 1822, Babbage wrote a scholarly paper describing a machine that could compute and print lengthy scientific tables. That same year he built a preliminary model of his "DIFFERENCE ENGINE" made with toothed wheels on shafts turned by a crank. He then enlisted the Royal Society, a prestigious association of scientists, in a bid for government grants to construct a full-scale working version. In 1833, Babbage was ready to put aside his plans for the DIFFERENCE ENGINE. Considering its troubled history, that was hardly surprising. Yet, he went on to develop ideas for an even more ambitious machine. The ANALYTICAL ENGINE, unlike its predecessor, was designed not just to solve one type of mathematical problem, but to carry out a wide range of calculating tasks according to the instructions supplied by its operator. It was to be "A Machine of the most general nature"- nothing less infact, than the first general-purpose programmable computer.
The Analytical Engine was to have a "MILL" and a "STORE," both composed of cogs and wheels. The store would hold up to 100 forty-diget numbers at a time. Numbers would be kept in the store until their turn came to be operated on in the MILL. Results would then be moved back into the store to await further use or to be printed out. Instructions would be fed into the Analytical Engine by means of PUNCHED CARDS. "We may say most aptly that the Analytical Engine weaves algebraical patterns just as the Jacquard-loom weaves flowers and leaves, " wrote the countess of Lovelace, one of the few people who comprehended both the machine's methods and its vast potential for application.
If your interested, you can go to the library and read more on Charles Babbage, he was quite fascinating .
Now lets take a look at what really happens after you turn on your computer. The steps involved in starting your computer (Booting it up) are very complicated, but I have listed here a simplistic overview for you.
First, we turn the power on. At this point, the computer is pretty dumb and doesn't know what to do, so there is a component in the computer (on the mother board) called a ROM (READ ONLY MEMORY) Chip. The basic purpose of this chip is to look at the computer and see what drives, memory and other equipment are attached to it. It also does a check of everything called a P.O.S.T. which is an acronym for POWER ON SELF TEST. When this is completed, the computer chip or ROM looks for your operating system, which is usually DOS (Disk Operating System) and Windows, a Microsoft product that comes on all computers now and works with your DOS. Once the ROM has all the information it needs, it passes control over to your operating system. The operating system now looks at some files on your Hard Drive Disk called the Config.sys and Autoexec.bat files. These files tell the operating system how to proceed and what to do.
The rest is history. Your computer displays all the nice files on your desktop (Screen) and you simply make a choice with your mouse and execute a program.
Denny Knutson, LPN,EMT, Maa
Emergency Room Nurse
Source: www.articletrader.com
