China DOS Union

The version of Grub I installed is 2007 - 11 - 24. My 80G hard disk has only one primary partition (C drive), and there are three logical partitions D, E, F left; I installed Grub in the Mbr. After normal startup of Grub, when using the filename auto - completion function, I found that the F drive was not recognized! The prompt of Grub is: "Notice: Number of heads for drive 80 tuned from 240 to 255".

What does the above prompt mean? Why can't Grub recognize my last partition? But it can be recognized and used normally in Windows. Is it a Grub bug, or is my Bios too old or has a bug?

I just discovered that the F drive is in NTFS format, no wonder! Does GRUB4DOS only recognize partitions in FAT32 format?

This is not the case, but I haven't tried having as many partitions as you do. I also tried an 80G hard drive, only divided into 2 partitions, one primary partition in FAT32 format with 2.99GB and one extended partition in NTFS format. The MBR can normally find GRLDR placed in the NTFS partition and boot.

Execute the following sequence at the GRUB command line:

debug 0x7FFFFFFF
geometry (hd0)
geometry (hd1)

Copy the displayed information.

After booting GRUB, enter the following commands in the command line:

debug 0x7fffffff

geometry (hd0)

GRUB feedbacks the following information:

int13/41 (80), version=AA210005

int13/48 (80), err=0,C/H/S=38325/16/63,Sector Count/Size=156368016/0

int13/08 (80), version=0,C/H/S=55143/255/63

int13/02 (80), err=0,

Warning: MBR cylinders(58590) is not equal to the BIOS one(55143)

Warning: MBR heads(240) is not equal to the BIOS one(255)

Warning: MBR total sectors(885880800) is greater than the BIOS one(885872295)

Some buggy BIOSes could hang when you access sectors exceeding the BIOS limit.



Notice: number of head for drive 80 tuned from 240 to 255



drive 0x80(LBA):C/H/S=58590/255/63,Sector Count/Size=885880800/512

int13/41 (80),version=AA210005

int13/48 (80),err=0,C/H/S=38325/16/63,Sector Count/Size=156368016/0

int13/08 (80),version=0,C/H/S=62252/255/63

int13/02 (80),err=0

Warning: MBR cylinders(66143) is not equal to the BIOS one(62252)

Warning: MBR heads(240) is not equal to the BIOS one(255)

Warning: MBR total sectors(1000082160) is greater than the BIOS one(1000078380)

Some buggy BIOSes could hang when you access sectors exceeding the BIOS limit.



Notice: number of head for drive 80 tuned from 240 to 255



Partition Num:0       File System Type is Fat,0xc

Partition Num:4       File System Type is Fat,0xb

Partition Num:5       File System Type is Fat,0xb

In addition, it is suggested that Grub should have a screenshot function or a display redirection command, so that everyone can post error messages conveniently. It's too tiring for me to copy line by line!

The last partition may have been protected by the BIOS, making it impossible for external programs to access it. Search for "HPA partition" in Google to find relevant topics.

Partitions protected/hidden by the BIOS are not accessible by GRUB.

I don't understand what you said:

The last partition may have been protected by the BIOS, making it impossible for external programs to access it.

Why would the BIOS protect the last partition? If the last partition is in Fat32 format, will it still protect it? After I flashed the new version of the BIOS, I could normally see all partitions, but I didn't use the new one.

My BIOS is an older version (dated September 11, 2001), it's an Award BIOS. The mainboard manufacturer's homepage has the latest version. I didn't use the latest version for the following reasons:

• The latest BIOS is based on Phonix Award and cannot flash ROMOS.
  
• After flashing the latest BIOS, it couldn't boot the existing XP in the hard disk, while the old version of the BIOS could boot normally.
  

grub4dos can only recognize the hard disk with the help of BIOS. If there is a bug in the BIOS that causes the real-mode DOS to be unable to access the last partition of the hard disk, then grub4dos cannot access it either. If the pure DOS in real mode can access the last partition, then grub4dos should also be able to access the last partition. If neither DOS nor grub4dos can access the last partition, it indicates that the problem is not with grub4dos but with the BIOS, and you don't need to solve it. The inability to access the hard disk partition in real mode does not affect the access of Windows/LINUX to the hard disk partition.

This problem is also irrelevant to what file system the partition is and only related to the BIOS.

You can further study whether this is the case.