 |
|
|
|||
 |
|||||
 |
 |
 |
 |
||
 |
|||||
|
Training at Georgetown: Introduction to ComputersThis course is a basic introduction to the hardware that UIS supports. You will learn the Basic Terminology UIS supports personal computing on both IBM-standard and Macintosh computers. In order to explain difficulties you experience with each type, knowing specific information about both types of hardware is beneficial. There are, however, some basic concepts and terms common to both: The first term is a byte which represents a single unit of data. A byte by itself is ineffective; computers nowadays have 2 or 5 gigabytes (1 gigabyte or GB is one billion bytes). Computers are electronic devices that deal in pulses of electricity. All data is reduced by the computer into a series of digits that turn ON and OFF electrical circuits. Each letter in your word processing document and each number in your spreadsheet are reduced to a combination of 1s and 0s. A bit is a single binary digit (either a 1 or a 0). Bits are combined into units called bytes. It takes one byte to represent a single alpha or numeric character [A-Z or 0-9]. Even a space, punctuation mark, or a function command is represented by bits and bytes and take up storage on the computer. We measure a computers size and power in terms of the number of byes it can store in memory or on its hard disk. Because a computer must store multiple data, we usually refer to memory or hard disk size in terms of kilo byes (kb) or megabytes (Mb). 1,000 bytes = 1 Kilobyte (Kb) A computer is an electronic device which stores and processes information. To function effectively, a computer must perform several types of functions. Each function is handled by a separate component. Basically, there are four types of components:
Input Device: Unlike the human brain, a computer cannot generate new ideas by itself. Therefore a computer must receive information or instructions from elsewhere. You communicate with your computer through an input device. The input device is the yes or the ears of the computer due to the method that it takes in new information. A computer must have at least one input device. Most computers have more than one input device. Examples of input devices include:
Output Device: In order to convey information back to the user, a computer must have a way of ?talking back?. The output device is the mouth of the computer, or the way it sends out information. Examples of output devices include:
Storage Units: The computer must have a place to store all of the information it processes. A storage unit can be any medium in which that information is stored. Examples of storage units include:
A hard disk is normally installed in the main body of the computers central processing unit; therefore it is called an internal hard disk. In some cases, a hard disk may be attached with a cable to the computer. This is an external hard disk. The other types of storage units all require that the computer be equipped to "read" data from those types of media. To store data on a CD, the computer must have a CD drive; to store data on a magnet tape, the computer must be concerto a tape drive, to use data from a CD-R, it must have a connection to a CD-R drive. A CD drive can be built into the computer or can be connected externally. Most other types of drives (tape drive, CD-R drive, and videodisc player) are external hardware which are connected with a cable to the computers central processing unit. All storage devices are evaluated by how much data they can hold. The amount of data they hold is usually measured in megabytes (Mb) or gigabytes (Gb). Central Processing Unit (CPU). The most important part of the computer is simultaneously the one which usually requires the least maintenance or interference with. The central processing unit (CPU) is the main body of the computer which is responsible for processing information. It is the command and control center (brain) of the computer. The most common CPU chip is made by Intel, called the Pentium with speeds that exceeding 3 gigahertz (GHz). Computers also depend on two other types of components which are essential to memory and speed. In addition to storage (hard disk) capacity, memory and speed indicate the power of the computer. Memory refers to the computers capacity for storing information while that information is processed. Memory is the PRIMARY STORAGE capability of the computer. Floppy disks and hard disks are types of SECONDARY STORAGE. There are two types of internal memory: 1) random-access memory (RAM) and read-only memory (ROM). ROM: Certain information essential to the operation of the computer is stored internally on chips on the computers central processing unit (CPU) board. These chips represent the machines ROM. The instructions provided by ROM usually contain simple programs that tell the computer where to find and load the computers operating system, and other basic information. Users do not usually need to know much about ROM or the information contained therein. The information contained on the ROM chips is not usually upgraded or altered. Data and Program Files: When you write and save a paper using a word processing program, you have created a data file. The data contained in that file (document) are the individual words, letters and numbers you typed as you wrote the paper. The software that enables you to write that paper on the computer is called the program file. The program file (for example, WordPerfect) is an independent set of instructions which tell the computer what to do. The data file is just information that contains the words and numbers which the program processes. In the world of DOS based (IBM-standard) computing, program files are called executable files because they "execute" Commands and instructions, they are usually designated by having an .EXE extension at the end. Command (.COM) and batch (.BAT) files are also program files because they contain instructions for the computer. Data files, however, are the everyday files you create using your spreadsheet, database or work processing program. They can have any valid extension that you assign them. Formatting: Formatting is the process by which a floppy diskette is prepared to store data. An unformatted floppy straight out of the box contains an unorganized array of magnetic particles. Formatting sets the disk up, organizing it into tracks and sectors; it creates a directory on the disk, and checks for bad spots. Because Macintosh and IBM standard machines each use their own proprietary disk format, disk formatted on one machine CANNOT be read by others. There are some exceptions to this rule, but normally if you put an IBM - standard formatted diskette in a Macintosh computer it will be rejected as unreadable, and vice versa. Whenever you re-format a diskette that has been previously formatted YOU ERASE ALL PRE - EXIDTING DATA on the disk. Care and Feeding of Storage media: It is important to treat them with care in order to preserve the data. It is a good idea to remind users to ALWAYS back up their data, keeping current versions of all data two places - - usually on a hard disk or as well as on a CD - Rom. Keep floppies and floppy drives away from:
Although we have already discussed the basic components of a personal computer, it is important to know how that information translates to a particular type of system. The various components are generally connected up to the back panel of the central processing unit. Expansion Slots: Additional features and functions can be added to a computer by installing additional printed circuit boards (PC boards). This is possible because of the expansion slots in the machine (slots provided for additional boards). Types of features you might add by installing additional boards might include a modem, a math co-processor, a mouse, etc., Portable computers and laptops provide less flexibility precisely because they do not have any expansion slots (so no new boards can be added once the unit is purchased). Ports: You will notice several types of connectors on the back panel. A connector that is used for the transfer of data is called a port. There are two basic types of ports. A parallel port transmits data one BYTE at a time. It is called a parallel port because each of the eight bits in a byte is transmitted simultaneously along eight separate lines. Because these are more efficient and trouble free, parallel ports are usually used to connect to printers. A ribbon cable is generally used to connect the parallel port to the printer. On IBM-standard machines, the parallel port is easy to spot because it is a large 25 pin D connector. A serial port sends data over only one line. It can send only one bit at a time, in series. To send a byte, for example, it would have to send each bit comprising the byte in turn. The serial port is smaller pin D connector on the back panel of the CPU. There are also SACS ports that usually are not reinstalled on computers that are 25 pin Serial connections that are now faster than parallel connections. A particular machine can have several parallel and serial ports; usually they come with one of each type. Parallel ports are designated LPG, LPG, and Serial ports are designated COMA, COMA, . . . Monitors and Video Adapters IBM-standard computers can be configured with a variety of monitors. Monitors vary in their ability to display in black and white or color, and in the quality of screen resolution. Because the monitor is driven by the CPU, each computer must have a special PC board called a video card or a video adapter installed in the CPU. The type of video adapter installed must correspond to the monitor used. Some common video adapters include:
It is important to know which type of adapter a particular computer has when configuring a particular machine for use with a particular software package. Some software packages require a specific type of adapter or require that you specify what you are using. Drives: Although they are usually built into the body of the CPU, floppy disk drives and hard drives are simply independent components that can be added or removed from a computer. In addition to being built into the machine, hard drives can be an external drive (separate boxes attached to the CPU with a cable). External hard drives are more common in Macintosh configurations than in the IBM-standard keyboard. Keyboard: Keyboards come in different configurations. Generally, there are three different areas on the keyboard. The typewriter section is the main body of the keyboard containing alpha and numeric keys laid out in the same order as a typewriter. The numeric keypad to the right contains numeric characters laid out like a calculator. Finally, function keys (F1, F2, etc.,) are laid out either in a bank to the left or horizontally across the top of the keyboard.
|
|||||
|
|||||
|
|||||
 |