Computer System Error Beep Codes

Power On Self Test Beep Codes

The computer POST (Power On Self Test) is the process of testing the computer system, insuring that it meets the necessary system requirements and that all hardware is working properly before starting the remainder of the boot process. If the computer passes the POST, the computer will have a single beep (with some computer BIOS manufacturers it may beep twice) as the computer starts and the computer will continue to start normally. However, if the computer fails the POST, the computer will either not beep at all or will generate a beep code, which tells the user the source of the problem.

Each time the computer boots up the computer must past the POST. Below is the common step a POST performs each time your computer starts.

1. Test the power supply to ensure that it is turned on and that it releases its reset signal.
2. CPU must exit the reset status mode and thereafter be able to execute instructions.
3. BIOS checksum must be valid, meaning that it must be readable.
4. CMOS checksum must be valid, meaning that it must be readable.
5. CPU must be able to read all forms of memory such as the memory controller, memory bus, and memory module.
6. The first 64KB of memory must be operational and have the capability to be read and written to and from, and capable of containing the POST code.
7. I/O bus / controller must be accessible.
8. I/O bus must be able to write / read from the video subsystem and be able to read all video RAM.

If the computer does not pass any of the above tests, your computer will receive an irregular POST. An irregular POST is a beep code that is different from the standard one or two beeps. This could be either no beep at all or a combination of different beeps indicating what is causing the computer not to past the POST.

Example of a Computer Error Beep Codes

Beep Code	Description of Problem
No Beeps	Short, No power, Bad CPU/MB, Loose Peripherals
One Beep	Everything is normal and Computer POST is fine
Two Beeps	POST/CMOS Error
One Long Beep, One Short Beep	Motherboard Problem
One Long Beep, Two Short Beeps	Video Problem
One Long Beep, Three Short Beeps	Video Problem
Three Long Beeps	Keyboard Error
Repeated Long Beeps	Memory Error
Continuous Hi-Lo Beeps	CPU Overheating

Various Testing Performed on a Computer System

To be able to pass the TESDA NC II Computer Servicing Exam you need also to learn about Various Testing procedure performed on a computer System. System testing of software or hardware is testing conducted on a complete, integrated system to evaluate the system's compliance with its specified requirements. As a rule, system testing takes, as its input, all of the integrated software components that have successfully passed integration testing and also the software system itself integrated with any applicable hardware system(s). The purpose of integration testing is to detect any inconsistencies between the software units that are integrated together (called assemblages) or between any of the assemblages and the hardware.

The following examples are different types of testing that should be considered during System testing:

GUI SOFTWARE TESTING

Is the process of testing a product that uses a graphical user interface, this is to ensure that it meet its written specifications. This is normally done through the use of a variety of test cases. Most clients in client/server and web-based systems deliver system functionality using a GUI. When testing complete systems, the tester must grapple with the additional functionality provided by the GUI. GUIs make testing systems more difficult for many reasons: the event-driven nature of GUIs, unsolicited events, many ways in/many ways out and the infinite input domain problems make it likely that the programmer has introduced errors because he could not test every path.

               

Graphical user interface is a type of user interface which allows people to interact with electronic devices such as computers; hand-held devices such as MP3 Players, Portable Media Players or Gaming devices; household appliances and office equipment with images rather than text commands. A GUI offers graphical icons, and visual indicators, as opposed to text-based interfaces, typed command labels or text navigation to fully represent the information and actions available to a user. The actions are usually performed through direct manipulation of the graphical elements.