PC Hardware

Lesson Summary

The following points summarize the main elements of this lesson:

  • Understanding ROM BIOS is key to keeping a computer up and running.

  • CMOS setup defines the data a computer needs to communicate with its hardware (such as its drives).

  • The CMOS battery maintains BIOS data when computer power is turned off.

  • POST cards can quickly repay their expense by helping to isolate problems when the POST routine fails to provide a report.

Tutorial Summary

The following points summarize the key concepts in this tutorial:

Computer Cases

  • The function of the case is to house the computer's internal components, connect the computer to the outside world with ports and connectors, and to protect the computer from damage.

  • To prevent electromagnetic interference, avoid running a computer without the cover on.


  • The motherboard defines the capabilities of a computer.

  • Not all motherboards are the same. Some manufacturers have proprietary motherboards that can be used only in their own computers. They will also require proprietary parts for expansion. Generally, these motherboards are of higher quality (and price).


  • BIOS chips are used to provide data to the CPU; this data tells the CPU how to operate specific devices.

  • CMOS is a BIOS chip that can have its data updated. The CMOS setup program is used to make these changes.

  • CMOS chips require a battery to save the data when power to the computer is off.

  • Some of the newer BIOS chips are updatable. These are called flash BIOS.

  • A device driver is a program that acts as an interface between the operating system and the control circuits that operate the device.

  • On machines running MS-DOS, device drivers are loaded by the CONFIG.SYS file.

  • Computers running Windows 95, 98, or 2000 load their own device drivers and do not require a CONFIG.SYS file.

  • POST is used to check a computer before it boots.

  • POST errors are indicated by beeps before the video is checked and by text after the video check.


  1. What is the main function of the motherboard?

  2. Name the typical chips found in a chip set.

  3. What is EMI?

  4. What are ROM chips used for?

  5. Name the three types of ROM chip.

  6. Describe what makes the CMOS special.

  7. How can a technician use the POST beep codes?

  8. What is a device driver?

  9. What information is contained in the CMOS?

  10. Define the POST and describe its function.