Hardware Reference
In-Depth Information
No boot sector on fixed disk -
strike F1 to retry boot, F2 for setup utility
Older IBM BIOS:
The IBM Personal Computer Basic
Version C1.10 Copyright IBM Corp 1981
62940 Bytes free
Ok
Note
Some IBM computers since 1987 display a strange character graphic depicting the front of
a floppy drive, a 3 1/2-inch disk, and arrows prompting you to insert a disk in the drive and
press the F1 key to proceed.
Older Compaq BIOS:
Non-System disk or disk error
replace and strike any key when ready
Although the messages vary from BIOS to BIOS, the cause for each relates to specific
bytes in the MBR, which is the first sector of a hard disk at the physical location cyl-
inder 0, head 0, sector 1.
The problem involves a disk that either has never been partitioned or has had the
Master Boot Sector corrupted. During the boot process, the BIOS checks the last two
bytes in the MBR (first sector of the drive) for a signature value of 55AAh. If the last
two bytes are not 55AAh, an Interrupt 18h is invoked, which calls the subroutine that
displays one of the error messages just shown, which basically instructs the user to in-
sert a bootable floppy to proceed.
The MBR (including the signature bytes) is written to the hard disk by the FDISK,
Disk Management, or DISKPART programs. Immediately after a hard disk is low-
levelformatted,allthesectorsareinitializedwithapatternofbytes,andthefirstsector
does not contain the 55AAh signature. In other words, these ROM error messages are
exactlywhatyouseeifyouattempttobootfromaharddiskthathasbeenfreshlylow-
levelformattedbuthasnotyetbeenpartitionedoriftheMBRhasbeencorruptedsuch
that the signature bytes were overwritten.
21. The MBR searches its built-in partition table entries for a boot indicator byte mark-
ing an active partition entry.
22. If none of the partitions are marked active (bootable), the BIOS invokes software
interrupt 18h, which displays an error message (refer to step 20).
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