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2.3.3 IML, POST, and BIOS
The systems use Initial Machine Load (IML) to store the power-on self-test
(POST) and Basic Input/Output System (BIOS) code.
code is stored in ROM and is used for preliminary testing during power-on.
The balance of the POST and BIOS code, called the IML image, is stored in
a protected partition on the default hard disk drive.
loaded onto the default hard disk drive when the system is manufactured.
At power-on, the first stage of POST is started from ROM.
stage, POST performs the following functions:
Checks the basic system-board and processor-board functions
Initializes the video function
Checks the memory subsystem
Verifies that the default hard disk drive is functioning
Verifies that the default diskette drive is functioning
Verifies that the IML image is installed in the protected partition of
the hard disk drive.
When the first stage of POST is complete, the IML image is loaded into RAM
from the System Partition on the default drive, even if the Reference
Diskette is in the diskette drive.
load the IML image from the Reference Diskette is if any of the following
conditions exist:
An error occurred reading the System Partition
A hardware failure occurred
The override jumper was moved (prior to power-up).
The second stage of POST is started from RAM.
tests of the hardware and initializes the system.
of POST is complete, system control is given to the operating system.
The partition also includes the system programs and the customer and
advanced diagnostic programs.
drive is formatted using the operating system format command.
Errors During POST:
If POST detects a problem, an eight-digit error code
is displayed.
Note:
On the Model 95, during POST the system displays the letters CP on
the information panel, followed by a two-digit code.
changes as the system progresses through POST.
indicate system status.
occurred.
For more information, see "Check Point Codes" in the
Hardware Maintenance Service pamphlet.
Replacing the Default Hard Disk Drive:
disk drive, you must recopy all of the system programs onto the
replacement hard disk drive.
1.
Start the system using the customer's backup copy of the current
System Partition.
2.
Select Backup/Restore system programs from the Main Menu.
3.
Run the Restore the System Partition option to load the IML image, the
system programs, and the customer and advanced diagnostic programs
onto the default hard disk drive.
Notes:
1.
If the user's backup copy of the System Partition is incomplete, you
will not restore the entire System Partition.
you have recopied the IML image, get the option diskettes and use Copy
an option to recopy the option files onto the System Partition.
2.
If the IML image is loaded onto the hard disk drive, but the
customer's operating system has not been loaded, the Insert-Diskette
icon will appear on the screen.
For information on system programs, see the Diagnostic Information for
Micro Channel Computers pamphlet.
IBM PS/2 Model 90 XP 486 and 95 XP 486 HMR
IML, POST, and BIOS
With IML, some of the
The only time the system attempts to
It performs additional
When the second stage
The partition is not affected when the
They do not mean that a failure has
If you replace the default hard
To recopy the programs:
If this occurs, after
¦ Copyright IBM Corp. 1990, 1992
2.3.3 - 1
The IML image is
During this
The code
The "CP" codes
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