The type and number of computers that make up a system have a direct bearing on the configuration and setup of a system. Some systems require two or three computers connected in tandem. An example is a CDS/NTDS for a particular class of ship, which may use   a   three-bay/one-bay   configuration   for   its CDS/NTDS.  Others have only one computer. An example is a PC in an office setting. Hardware When  Configuring  or  setting  up  a  computer  system for  operation  or  maintenance,  check  your  computer’s technical,  system  operations,  or  combat  systems technical  operations  manuals  for  the  correct  physical setup. Set up includes the following: .  Physical  design l  Operator  controls .  External  controls PHYSICAL   DESIGN.—   The  design  of  the computer  system  will  predetermine  how  and  where module units and printed circuit boards need to be inserted and where cables are to be connected. Once these items are correctly installed and connected, the next step is to ensure that all operator controls are in their correct positions. OPERATOR CONTROLS.— Computers can be controlled directly at the computer and in some cases remotely through panels/consoles. Mainframe and large minicomputers usually have controls for the computer  at  your  fingertips.  You  can  control  the computer from several panels/consoles as follows: l  Maintenance  panel/console l Operator panel/console l Remote panel/console (usually only mainframes for tactical systems have this capability) The types of controls these units most often use are discussed in more detail in chapter 3 of this manual. You  can  also  control  the  computer’s  mode  of  operation directly   from   the computer’s    maintenance panel/console or operator’s panel/console. This feature is not available on all computers. Figure  1-8  shows  a  portion  of  a  maintenance panel/console of a mainframe computer. For example, notice  the  mode  select  push-button  indicator,  jump switches, and stop switches. You can use the jump switches  and/or  stop  switches  when  performing 1-10 maintenance to set parameters for a diagnostic on the computer. EXTERNAL CONTROLS.— Some computers use  external  controls  to  configure  and  set up the computer to enable it to communicate with peripherals and other systems. These controls work in conjunction with the software. Unless these controls are configured and set up properly, the computer cannot perform its functions correctly. The controls may be set through digital  switchboards  or  computer  switching  and  control panels. Figure 1-9 is an illustration of a computer switching and control panel used on a CDS/NTDS system. Notice the push-button indicator switches available. You   can   use   these   to   control   the configuration and data routing. Software Once you have the hardware of the computer physically configured and set up correctly, the correct software must be installed and correctly configured/set up. When we speak about configuring and setting up the  software,  we  are  referring  to  specifying  the resources the software is to use—what peripherals the system  has,  what  communications,  how  much  memory, what options you want set as defaults, and so on. In this way the hardware and software can talk to each other. The software and hardware have to work hand-in-hand with each other. Depending on the type of computer and type of system application, the hardware and software have the ability to control and/or are dependent on each other. Perform the following procedures when working with software: Figure  1-8.—A  portion  of  a  maintenance  panel/console  of  a mainframe  computer.