System Configuration Definitions and Terms Chapter Objectives After completing this chapter you will Understand the different ways to configure a microcomputer Understand how to replace a battery Understand and be able to identify system resources such as interrupts DMA channels memory addresses and I O addresses Understand how different architectures and local bus adapters are configured Understand the effects of plug and play Windows 9x NT 2000 and XP on configuring adapters Configuration Overview Setup program Used to configure a computer system It indicates How much RAM is installed The type and number of hard drives and floppy drives Where the boot disk is located Date and time etc Displays an error message if information in the setup program doesn t match the hardware or if a specific device fails to operate properly Setup Software Most computers require Setup software to access the Setup program that is often built into the BIOS chip and accessed by specific keystrokes Sometimes BIOS requires updating and this can require replacing one or more chips on the motherboard or using an executable file Computers may need a BIOS upgrade for supporting more floppy drives higher capacity hard drives virus protection password protection or to solve problems with the current BIOS Setup Software Setup Keystrokes Configuration Table 1 Flash BIOS Flash BIOS A type of memory that allows the BIOS to be changed without installing a new chip The BIOS is updated via files that have been downloaded from the Internet Viruses can infect the Flash BIOS Keep the BIOS write protected until you need to update it CMOS Memory CMOS Complementary Metal Oxide Semiconductor chip A special type of static memory on the motherboard that holds the setup configuration information CMOS holds the computer s current configuration information Part of the BIOS software routine that runs after power on checks CMOS for information about which components are supposed to be installed After the information is read from CMOS these components are tested This the POST described in Chap 1 which runs whenever the computer cold boots A small battery on the motherboard keeps the CMOS memory from losing the setting information If the battery dies the information is lost and must be reentered The wrong configuration information causes POST error codes or error messages that might indicate a hardware problem The correct Setup information should be kept by a technician for each computer The wrong information entered into the Setup program may cause the computer to operate improperly or fail to boot Advanced Configuration Information Many computers have an Advanced Setup with the following options Boot Sequence This option determines if the computer looks first to the floppy drive the hard drive CD or DVD drive for the operating system System BIOS Shadow or System BIOS Cacheable This setting puts a copy of the software contained in the BIOS into RAM PNP PCI Configuration Setup This option is used to configure the PCI slots configure the computer for a PNP operating system and allow the BIOS to control IRQ and DMA assignments Power Saver This option turns the system off after a period of non use When installing a new system use the default BIOS settings until all components are tested Passwords that have been set and forgotten can be cleared by jumpering pins together to clear either the power on password or all of the CMOS settings Batteries Computer batteries come in various shapes and sizes the most common today being a lithium battery about the size of a nickel see Fig 1 They slide into a special holder making them easy to change Older computers also used a cylindrical battery about 1 5 inches long that was soldered to the motherboard but these batteries usually failed in a few years and were difficult to change Other computers use a 3 6 volt cylinder of lithium batteries or alkaline 4 5 volt batteries AA flashlight batteries were also used in a special holder and mounted inside the computer using velcro Other manufacturers use their own version of a battery pack Batteries Motherboard with Lithium Battery Configuration Figure 1 Batteries Computer Batteries Configuration Figure 2 Laptop and Device Batteries Up until 1996 the most popular laptop battery was the NiCad Nickel Cadmium battery NiMH Nickel Metal Hydride batteries replaced the NiCad These were lighter and stored 50 more power Li Ion Lithium Ion batteries are replacing the NiMH which are very light and can hold a charge longer than any other type of battery but are also expensive Li Ion Polymer batteries are similar to Li Ion but are packed in pouched cells allowing for smaller batteries and more efficient use of space Zinc Air battery is environmentally friendly and hold a charge for extended amount of time Fuel Cells an upcoming technology that can hold a charge for 5 to 10 hours when used with a laptop Replacing a Battery Computer batteries last 7 to 10 years with Li Ion batteries currently lasting the longest Some technicians will change a battery with the power on to prevent the loss of configuration information The only way to ensure the settings aren t lost is that setup configurations must be printed or written down before replacing a battery Always refer to the motherboard documentation for the proper battery specifications and follow all manufacturer instructions for the proper way to change the battery Plug and Play PnP or Plug and Play A specification that allows automatic configuration of an adapter There are 3 conditions that must be met for plug and play to work The following items must support plug and play The motherboard BIOS The adapter that s being installed The operating system Adapters that are PnP may still need a device driver loaded due to the operating system or an updated version of the driver being available Configuration Through Switches Some older computers do not have batteries or CMOS memory to store the configuration information instead they are configured using special switches on the motherboard called DIP switches DIP switches Used to set the computer s configuration and located on the motherboard or sometimes ISA adapters There are two basic models of DIP switches slide and rocker Slide DIP Switch With a slide DIP switch a sliding tab sticks up out of the switch bank for each switch that can be turned either on closed or 1 or off open or 0 Switch bank A group of DIP switches located together on the motherboard There are many