Large Disk HOWTO

• Index
• Large disks
• Units
• Disk Access
• History of BIOS and IDE limits
• Booting
• Disk geometry, partitions and `overlap'
• Translation and Disk Managers
• Kernel disk translation for IDE disks
• Consequences
• Details
• Clipped disks
• The Linux 65535 cylinder limit
• Extended and logical partitions
• Problem solving

Large Disk HOWTO

Andries Brouwer, aeb@cwi.nl

For the most recent version of this text, see www.win.tue.nl.

1. Large disks

2. Units

3. Disk Access

• 3.1 Cylinders, heads and sectors
• 3.2 Sectorsize
• 3.3 Disksize
• 3.4 The 1024 cylinder and 8.5 GB limits
• 3.5 The 137 GB limit

4. History of BIOS and IDE limits

5. Booting

• 5.1 LILO and the `lba32' and `linear' options
• 5.2 A LILO bug
• 5.3 1024 cylinders is not 1024 cylinders
• 5.4 No 1024 cylinder limit on old machines with IDE
• 5.5 Other boot loaders

6. Disk geometry, partitions and `overlap'

• 6.1 The last cylinder
• 6.2 Cylinder boundaries

7. Translation and Disk Managers

8. Kernel disk translation for IDE disks

• 8.1 EZD
• 8.2 DM6:DDO
• 8.3 DM6:AUX
• 8.4 DM6:MBR
• 8.5 PTBL
• 8.6 Getting rid of a disk manager
• 8.7 Since 2.5.70: boot parameters

9. Consequences

• 9.1 Computing LILO parameters

10. Details

• 10.1 IDE details - the seven geometries
• 10.2 SCSI details

11. Clipped disks

• 11.1 The Linux IDE 8 GiB limit
• 11.2 BIOS complications
• 11.3 Jumpers that select the number of heads
• 11.4 Jumpers that clip total capacity
• 11.5 READ NATIVE MAX ADDRESS / SET MAX ADDRESS
• 11.6 CONFIG_IDEDISK_STROKE

12. The Linux 65535 cylinder limit

• 12.1 IDE problems with 34+ GB disks

13. Extended and logical partitions

14. Problem solving

• 14.1 Problem: My IDE disk gets a bad geometry when I boot from SCSI.
• 14.2 Nonproblem: Identical disks have different geometry?
• 14.3 Problem: 2.4 and 2.6 report different geometries?
• 14.4 Nonproblem: fdisk sees much more room than df?