- Watching the Boot-Up Procedure
- Hardware and Configuration Problems
- About This Article
Hardware and Configuration Problems
A functional computer system is composed of two major parts: the system's hardware and the software that controls it. These two elements are so closely related that it is often difficult to determine which part might be the cause of a given problem. Therefore, one of the earliest steps in troubleshooting a computer problem (or any other programmable system problem) is to determine whether the problem is due to a hardware failure or to faulty programming.
In PCs, you can use a significant event that occurs during the boot-up process as a key to begin separating hardware problems from software problems: the single beep most PCs produce between the end of the POST and the beginning of the boot-up process (step 7 in the preceding list).
Errors that occur, or are displayed, before this beep indicate that a hardware problem of some type exists. This conclusion should be easy to understand because up to this time, only the BIOS and the basic system hardware have been active. The operating system side does not come into play until after the beep occurs.
If the system produces an error message (such as "The System Has Detected Unstable RAM at Location x") or a beep code before the beep, for example, the system has found a problem with the RAM hardware. In this case, a bad memory device is indicated.
You can still group errors that occur before the beep into two distinct categories: configuration errors and hardware failures.
Configuration Problems
You can trace the majority of all problems that occur in computer systems back to configuration settings.
A special category of problems tends to occur whenever a new hardware option is added to the system, or when the system is used for the very first time. These problems are called configuration problems, or setup problems, and result from mismatches between the system's programmed configuration, held in CMOS memory, and the actual equipment installed in the system.
This mismatch also can be between the system's CMOS configuration settings and the option's hardware jumper or switch settings.
Normally, you need to run the system's CMOS Setup utility in these three situations:
When the system is first constructed.
If it becomes necessary to replace the CMOS backup battery on the system board.
Whenever a new or different option is added to the system (such as a hard drive, floppy drive, or video display), it might be necessary to run the Setup utility (but see the note "CMOS Setup Utility and Plug and Play").
CMOS Setup Utility and Plug and Play
In most newer systems, the BIOS and operating system use Plug and Play (PnP) techniques to detect new hardware that has been installed in the system. These components work with the device to allocate system resources for the device. In some situations, the PnP logic cannot resolve all the system's resource needs and a configuration error occurs. In these cases, you must manually resolve the configuration problem.
Configuration problems occur with some software packages when first installed. The user must enter certain parameters into the program to match its capabilities to the system's actual configuration. These configuration settings are established through the startup software in the ROM BIOS. If these parameters are set incorrectly, the software cannot direct the system's hardware properly and an error occurs.
When you are installing new hardware or software options, be aware of the possibility of this type of error. If you encounter configuration (or setup) errors, refer to the installation instructions found in the new component's User Manual. Table 1 lists typical configuration error codes and messages produced when various types of configuration mismatches occur.
Table 1 Common Configuration Error Codes
|
Configuration Error Message |
Meaning |
|
CMOS System Option Not Set |
Failure of CMOS battery or CMOS checksum test |
|
CMOS Display Mismatch |
Failure of display-type verification |
|
CMOS Memory Size Mismatch |
System configuration and setup failure |
|
Press F1 to Continue |
Invalid configuration information |
Test Tip
Know the situations that cause a Press F1 to Continue error message to display.
If you cannot confirm a configuration problem, the problem most likely is a defective component. The most widely used repair method is substituting known good components for suspected bad components. Other alternatives for isolating and correcting a hardware failure that appears before the boot up depend on how much of the system is operable.
These alternatives include running a diagnostic program to test the system's components and using a POST card to determine what problems a system might have. Several diagnostic software packages enable you to test system components. However, these diagnostic tools require that certain major blocks of the system be operational. The POST card is a device that plugs into the system's expansion slots and reads the information moving through the system's buses. It is used when not enough of the system is running to support any other type of diagnostic tool.
After the beep, the system begins looking for and loading the operating system. Errors that occur between the beep and the display of the operating system's user interface (command prompt or GUI) generally have three possible sources:
Hardware failure (physical problem with the boot drive)
Corrupted or missing boot files
Corrupted or missing operating system files
In these cases, checking the drive hardware is generally the last step of the troubleshooting process. Unless some specific symptom indicates otherwise, the missing or corrupted boot and operating system files are checked first.
This article has covered basic troubleshooting steps in determining hardware and configuration problems. By reviewing this information and paying special attention to the "Test Tip" boxes, you should be well prepared for questions on Objective 2.2 in the exam's Core Hardware module.