are correct for a job, selecting a utility program to copy a file or create a new file by specifying the parameters, and   working   with   an   online   database   management system that keeps up-to-date information on inventory management or personnel. In looking over these last few paragraphs, possibly you see yourself as a worker, a supervisor, a teacher, and a troubleshooter, and rightly so. Microcomputers make up a significant part of your profession; and because of this,  you  will  be  the  person  that  others  will  come  to looking for answers to their questions. The mere fact that  you  are  a  communications  specialist  gives  the outside world, the end users, the impression you know it all; that is, all there is to know about mainframes, minis, and particularly microcomputers. WORKING  WITH  HARDWARE Microcomputers  come  in  many  shapes  and  sizes with a variety of capabilities. A microcomputer can be designed to operate in a stand-alone  configuration or as a  component,  an  intelligent  terminal,  a  server  for  a complex   local-area   network   (LAN)   or   large distributed system.  In this chapter, we will focus our attention on desktop microcomputers that operate in a stand-alone  environment.  Most  stand-alone,  desktop microcomputer systems contain at least five hardware components. They are as follows: .  The  computer  or  system  unit,  which  normally houses   the   microcomputer   (microprocessor chip[s]) along with other hardware components and secondary storage devices; .  Secondary  storage  devices  (floppy  disk  drives, hard   disk   drives,   and   magnetic   tape   units), housed either in the system unit or separately; . A monitor (standard output device); . A keyboard (standard input device); and . A printer (an additional output device—for hard copy). THE  MICROCOMPUTER In  this  section,  we  will  examine  the  microcomputer with   its   individual   hardware   components.   We   will examine  it  from  the  inside.  You  will  see  how  the components   work   and   how   they   interface   and interconnect with one another. There will come a time when you maybe required to replace or add a board in a computer to upgrade or expand the capabilities of the system. A few examples are  as  follows: You may need to install an expanded memory board   to   increase   the   amount   of   RAM   to accommodate larger applications. You may have to replace the enhanced graphics adapter  (EGA)  board  with  an  video  graphics array   (VGA)   board   to   upgrade   the   graphics capabilities of your system. You   may   need   to   install   a   communications board. You   may   receive   a   new   software   release   that requires the presence (or absence) of certain boards to function properly. You do not want to find out too late that your software is incompatible with your hardware. You might have to answer questions such as the follow- ing: Will the graphics software the user wants to order work with the graphics board currently installed in the system? Does the user’s system have sufficient room to accommodate another hard disk drive? A diagnostics routine may indicate that the disk controller board needs to be replaced, and so on, and so on. For reasons such as these, you will need to know a lot more about microc- computers (both inside and out) if you are to be effective and able to help others in your work environment. The Computer or System Unit The  computer  or  system  unit  is  the  main  part  or heart of the total microcomputer system. Inside this unit all data is processed, arithmetic and logic functions are performed, and control is maintained for the system. If you  were  to  remove  the  outer  cover  from  this  unit (figure 1-8), you would see a power supply and as many Figure  1-8.—A  microcomputer  system  unit  with  the  cover removed. 1-11