Basic knoledge of computer

Basic Computer Operations
How Computers Work
Input: Information and programs are entered into the computer through Input devices such as the keyboard, disks, or through other computers via network connections or modems connected to the Internet. The input device also retrieves information off disks.

Output: Output Devices displays information on the screen (monitor) or the printer and sends information to other computers. They also display messages about what errors may have occurred and brings up message or dialog box asking for more information to be input. The output device also saves information on the disk for future use.

Processing: The CPU or central processing unit is sometimes called the Control Unit and directs the operation of the input and output devices. The Coprocessor or the Arithmetic-Logic Unit does arithmetic and comparisons. The memory or RAM temporarily stores information (files and programs) while you are using or working on them. The BIOS or basic input/output system controls the dialogue between the various devices.

Keyboard Layout and Data Entry

ENTER or RETURN - Moves the cursor down one line and to the left margin. Enter also process commands such as choosing an option in a dialog (message) boxes and submitting a form.

DEL or DELETE - Deletes the character at cursor and/or characters to the right of the cursor and all highlighted (or selected) text.

BKSP or BACKSPACE - Deletes the character to the left of cursor and all hightlighted text.

SPACE BAR - Moves the cursor one space at a time to the right

SHIFT KEY - Use the shift keys to type capital letters and to type the upper character on keys with two characters on them

CAPS LOCK - Locks the keyboard so it types capital letters (a light goes on when caps lock is on)

TAB - Moves the cursor five spaces to the right (number of spaces are usually adjustable). Tab moves to the next field in a form or table (Shift-Tab for previous field).

ESC or ESCAPE - Cancels a menu or dialog box

ARROW KEYS - Moves the cursor around document without changing text

FUNCTION KEYS or F KEYS - Access commands by themselves or in combination with the three command keys; CTRL, SHIFT, and ALT

Command or Special Keys

Command keys normally do nothing on their own but work in combination with other keys. Each piece of software uses the command keys differently though there is a move to standardize some functions. The Control key or Ctrl is often used to access commands. The Alternative key or Alt is often used to access menus. The Shift key is used to type CAPITAL LETTERS. As well the command keys are all used to move through documents and edit text faster and easier. As well many computers have Special keys design specifically for the particular computer. Apple computers have the Apple keys and Macs have Command keys. Many keyboards now have a Windows key specifically for Windows 9x and newer systems. Many older computers also have special keys used for a variety of different functions.

Some Notebook or Laptop keys are left out because of space limitations and they usually have a Special function key which allows other keys to double for the missing ones.

Basic Typing Rules

Place one space between each word, after a punctuation mark and at the end of a sentence. Always start a sentence with a capital letter. Use capitals for names, addresses, provinces and countries, places, organizations, businesses, associations, schools, colleges, universities, days of the week, months, holidays, nationalities, ethnic groups and languages.

Learning the keyboard is the first step to learning computers. Learning involves practice. It really is as simple as that. There are two kinds of typing.

The first is called Touch Typing. The Touch Typist uses the Home Keys (asdf for the left hand and jkl; for the right) and all the fingers on both hands as well as the thumbs for the Space Bar while typing. There are many commercial and public domain programs that are designed to teach this method.

The other method is some times called 'Hunt and Peck' or depending on finger strength 'Search and Destroy'. This involves using one or more fingers on one or two hands to type. It is a perfectly acceptable way of using a computer and many people get along fine with this technique.

history of computer

An Illustrated History of Computer

Part 1

The first computers were people! That is, electronic computers (and the earlier mechanical computers) were given this name because they performed the work that had previously been assigned to people. "Computer" was originally a job title: it was used to describe those human beings (predominantly women) whose job it was to perform the repetitive calculations required to compute such things as navigational tables, tide charts, and planetary positions for astronomical almanacs. Imagine you had a job where hour after hour, day after day, you were to do nothing but compute multiplications. Boredom would quickly set in, leading to carelessness, leading to mistakes. And even on your best days you wouldn't be producing answers very fast. Therefore, inventors have been searching for hundreds of years for a way to mechanize (that is, find a mechanism that can perform) this task.

This picture shows what were known as "counting tables" [photo courtesy IBM]

A typical computer operation back when computers were people.

The abacus was an early aid for mathematical computations. Its only value is that it aids the memory of the human performing the calculation. A skilled abacus operator can work on addition and subtraction problems at the speed of a person equipped with a hand calculator (multiplication and division are slower). The abacus is often wrongly attributed to China. In fact, the oldest surviving abacus was used in 300 B.C. by the Babylonians. The abacus is still in use today, principally in the far east. A modern abacus consists of rings that slide over rods, but the older one pictured below dates from the time when pebbles were used for counting (the word "calculus" comes from the Latin word for pebble).

A very old abacus

A more modern abacus. Note how the abacus is really just a representation of the human fingers: the 5 lower rings on each rod represent the 5 fingers and the 2 upper rings represent the 2 hands.

In 1617 an eccentric (some say mad) Scotsman named John Napier invented logarithms, which are a technology that allows multiplication to be performed via addition. The magic ingredient is the logarithm of each operand, which was originally obtained from a printed table. But Napier also invented an alternative to tables, where the logarithm values were carved on ivory sticks which are now called Napier's Bones.

An original set of Napier's Bones [photo courtesy IBM]

A more modern set of Napier's Bones

Napier's invention led directly to the slide rule, first built in England in 1632 and still in use in the 1960's by the NASA engineers of the Mercury, Gemini, and Apollo programs which landed men on the moon.