Power-On Self-Test (Post) - IBM PS/2 65 SX Hardware Maintenance Reference

3.2 Power-On Self-Test (POST)

|The POST is initiated automatically each time the system power is turned
|on.
|The POST is a series of system checks and initializations that verify the
|correct operation of the system unit.
|that allow the system to be operational enough to run advanced
|diagnostics. The POST can detect two types of errors:
|noncritical.
|Critical errors prevent the system from operating or cause incorrect
|results that are apparent to the user.
|include microprocessor or interrupt-controller errors.
|detects a critical error, the microprocessor attempts to display the error
|and all testing stops.
|Noncritical errors cause incorrect results that might not be apparent to
|the user. An example of a noncritical error would be a serial
|communications failure.
|testing stops and the microprocessor displays an error code.
|F1 key allows testing to continue.
|When the Reference Diskette is in drive A, and a noncritical error is
|detected, the system displays the POST error message along with a message
|generated from the Reference Diskette.
|instructs the user to take a specific action to correct the error.
|After a successful POST, one short beep occurs.
|a BIOS routine called the system bootstrap loader.
|attempts to load an operating system or a program from either a diskette
|or the fixed disk drive.
|Diskette icon is displayed (see the &dia.
|icon indicates that a diskette should be inserted into drive A.
|diskette is inserted, press the F1 key to resume operation.
|is pressed when no diskette is in the diskette drive, the IBM Cassette
|BASIC screen appears.
IBM PS/2 Model 65 SX HMR
Power-On Self-Test (POST)
The POST tests only those areas
Examples of critical errors
If the POST detects a noncritical error, all
The Reference Diskette message
If neither is present in the system, the Insert
pamphlet in this manual).
3.2 - 1
critical and
If the POST
Pressing the
Control is then given to
The bootstrap loader
This
After the
If the F1 key