INTRODUCTION

Introduction to Computers is an article for students new to computers. We are living in an information age dependent upon digital information. Digital information is electronic information, the result of computer processing. Every type of job relies upon getting information, using it, managing it, and relaying information to others. Computers enable the efficient processing and storage of information. Do not think of a computer merely as the machine with the keyboard and the mouse, although that might be true for some types of computers. Embedded computers may be inside your household appliances, the VCR, the automobile, planes, trains, powerplants, water purification plants, calculators, and even inside a few toys. These embedded computers are very small. They affect our lives each day. Why, even modern traffic lights operate with computers. They are all around us. Think of additional ways in which computers affect our lives each day. The Four Operations of a Computer System Input Home computers are microcomputers. Input is supplied to the microcomputer with the use of a keyboard, a mouse, or another input device. These input devices may be called peripheral devices. Processing Processing is done inside the computer in an area called the central processing unit (CPU). Processing is the conversion of input to output. Storage Storage refers to holding information somewhere. RAM, Random Access Memory, is short-term memory. It is volatile memory because the memory is automatically "erased" when the power is turned off or interrupted. The RAM memory is located inside the computer case on the motherboard. A motherboard is not the keyboard. The keyboard is what you type with. A motherboard holds RAM memory, electronic circuits and other computer parts including the central processing unit. ROM, Read-Only-Memory, is not volatile meaning the memory is still there when power is interrupted or turned off. When the computer is turned back on again, ROM memory is still in storage on the internal hard disk. Output Output is the result of a computer process. Output may be viewed on a monitor screen, heard through speakers, printed on printers, and so forth. Output devices may be considered hardware and are also considered to be peripheral devices. A Basic Computer "System" A computer system refers to the computer AND all of its equipment. Equipment like speakers, printer, keyboard, scanner, etc. is called peripheral equipment, sometimes shortened to "peripherals". The central processing unit (CPU) is considered to be "the computer". Without peripheral equipment (such as monitor, printer, speakers, etc.) for input and output the microcomputer (home computer) will not be able to do anything you find useful. Your computer system cannot help you type a letter unless you have some type of software (program) to do this. Most typing is handled by a "word processing" program. A software program for your computer can be purchased at stores like Office Depot, Staples, and computer stores. Check your local telephone directory for a computer store in your area. Sometimes when you purchase a computer it already has a word processing program installed. If you buy a computer from a large electronics chain store, even if you have to travel out of town, you will get a better price as a rule than buying from a smaller chain store in town. Ask in town first, if they would be willing to match another store's Advertised price... See "Buying A Computer", next. Buying A Computer It is best to ask and to compare features before you buy a computer. The first question to ask yourself is, "What do I want a computer to do?" Do you need it only for e-mail and a little light letter writing or do you need it for graphics and Web page authoring? Will you also want extra storage for your music files or graphics files? Do you need any hardware for game playing? What type of Internet connection will you have: dialup, cable, DSL, or other broadband connection? Will you be needing a computer for school work? Accounting? Make a list of what you need the computer to do before you talk to anyone about purchasing a computer. Your needs will be different that those of the next person. Visit Computer Company Web sites. The PC vs. The Macintosh There are several computer systems available for home computing but the two most common types of computers are the PC (personal computer), manufactured by companies such as DELL, IBM, NEC, GATEWAY, HP, SAMSUNG, and others -- and the Macintosh manufactured by Apple Computer. The Macintosh Computer The Macintosh computer is commonly referred to as a "Mac". Apple Computer has produced a PowerMac, an iMac, and a PowerMac G4, and the PowerMacG5. The operating system of the PowerMac G4 or G5 has undergone revisions. Each major version also has a name: OS X version 10.2.x is Jaguar; version 10.3.x is Panther, and the version 10.4.x is Tiger. The Apple PowerMac computers(the G4 and the G5) have two processors (for parallel processing) instead of just one, and there is space inside the computer to upgrade to 4 hard disks in a RAID array to give more power to the computers functioning as a server. Sometimes the computer tower is called a "box" which is a slang word for "the computer". You could say, "there are two processors inside the box." There is software specially designed for the PowerMac computers to help move files from a Windows 98, ME, or 2000 system (XP is not listed on the box) to the Mac OS X. This software is called Move2Mac and is a product of Detto Technologies. I found my copy of the shrink-wrapped software on a shelf at a large Fry's Electronics store. A lot of computer software can be purchased using a credit card with a secure connection over the Web, then downloading that software to your own computer. I prefer having a CD or other disk with the software on the disk. Downloading via FTP is the process of moving files from another computer over a network connection to a local computer (like your own home computer) using File Transfer Protocol (FTP). If working at school or on the job you have to get permission to download files, for security reasons. You can download files using a Mac or a PC computer. Both use File Transfer Protocol. The Macintosh has excelled in the commercial graphics and publishing industries and thousands of people prefer a Mac for home use rather than a PC. The PC computers currently have a much greater market share and there are millions in use in homes and businesses throughout the world. When you attend college the college will specify which type of computer, Mac or PC, will be in use at the college for faculty and students. Some colleges use just Mac computers in campus buildings and for the faculty. Other colleges use PCs. Each PC running a specific operating system such as Windows 2000 is able to use any software that says WIN95/98/NT/2000 on the box. The Windows2000 operating system can also run any software specified for WIN95/98/NT/2000 as well as any software specified as Windows 9.x/NT/2000. If in doubt about buying the correct software for your system, the store clerks will be happy to assist you if asked. If you are using Windows XP, make sure that the software you buy has Windows XP included in the "System Requirements", usually found on the side panel of the box for shrink-wrapped software (boxed software). (In the following paragraphs I use OS to mean "operating system") Prior to the Macintosh OS X operating system the Macs used an operating system based upon a single processor (computer CPU) which processed data and ran applications using what was called cooperative multitasking. Cooperative multitasking allowed programs to sometimes take control of the central processing unit. Now with the newer Macintosh operating system, OS 10.2.x (Jaguar) and later versions there is a UNIX-like kernel in the operating system, two processors and the central processing unit processes data with symmetric multiprocessing (uses both CPU's or "chips" to process data) and it uses preemptive multitasking, not allowing any application to take control of the central processing units. If users want to run older software, the PowerMac G4 is a dual-booting machine meaning you can either boot into the older OS 9.2 or a version of OS X. (This is called "dual bootable".) Software written for the OS X (pronounced OS ten) will not run in the OS 9 environment but older legacy software is capable of being run while booted into the newer OS X, just that the newer features of the OS X will not be available when running applications designed for the OS 9 or older operating systems. The Mac G5's and newer versions of Os X have more multimedia features than the earlier G4's with the older versions of OS X. Get to the Apple Computer Web site for what's new now. The computer industry is not standing still... changes are rapid and one article online cannot capture what is now current. Central Processing Unit and Software Compatibility The computer processor inside a PC or PC-clone computer has totally different architecture (microscopic "wiring" schematic) inside the central processing unit chip (the CPU, or "chip"). In other words, the specific way the circuits are laid out in a computer chip (CPU, central processing unit) is called the chip architecture. PC chips and Mac chips have processing units with totally different architecture. Software is not interchangeable. Buy Mac software for the Macintosh and buy PC software for PC computers. An Apple or Mac computer is not a PC. Most PC Computers are sold new with a Windows operating system but keep in mind that other operating systems can also run on PC-architecture machines. One example of another operating system that can run on a PC machine is Linux for Windows. When two operating systems are on a disk they are installed on separate "partitions" of the disk. That is similar to two songs on one CD having to be on separate "tracks". Hardware and Software Usually, things you can see and touch on a computer or inside a computer are called "hardware" whereas programs for the computer (digital instructions) are called software. Software is created by a computer programmer who writes lines of code for the computer. An interpreter or compiler is a smaller program which changes the programmer's code into machine instructions for the central processing unit. After much testing and debugging, the programmer's code is finally "packaged" into executable files which make up the final "software" which can be purchased later, or might be "bundled" with the computer when you buy it (meaning that some software is already installed when you buy the computer.)