You got a new large disk. What to do? Well, on the software side: use fdisk (or, better, cfdisk) to create partitions, and then mke2fs to create a filesystem, and then mount to attach the new filesystem to the big file hierarchy.
You need not read this HOWTO since there are no problems with large hard disks these days. The great majority of apparent problems is caused by people who think there might be a problem and install a disk manager, or go into fdisk expert mode, or specify explicit disk geometries to LILO or on the kernel command line.
However, typical problem areas are: (i) ancient hardware, (ii) several operating systems on the same disk, and sometimes (iii) booting.
Advice:
For large SCSI disks: Linux has supported them from very early on. No action required.
For large IDE disks (over 8.4 GB): get a recent stable kernel (2.0.34 or later). Usually, all will be fine now, especially if you were wise enough not to ask the BIOS for disk translations like LBA and the like.
For very large IDE disks (over 33.8 GB): see IDE problems with 34+ GB disks below.
If LILO hangs at boot time, also specify linear in the configuration file /etc/lilo.conf. (And if you did have linear, try without it.) If you have a recent LILO (version 21.4 or later), the keyword lba32 will usually allow booting from anywhere on the disk, that is, the 1024 cylinder limit is gone.
There may be geometry problems that can be solved by giving an explicit geometry to kernel/LILO/fdisk.
If you have an old fdisk and it warns about overlapping partitions: ignore the warnings, or check using cfdisk that really all is well.
For HPT366, see the Linux HPT366 HOWTO.
If at boot time the kernel cannot read the partition table, consider the possibility that UDMA66 was selected while the controller or the cable or the disk drive did not support UDMA66. In such a case every attempt to read will fail, and reading the partition table is the first thing the kernel does. Make sure no UDMA66 is used.
If you think something is wrong with the size of your disk, make sure that you are not confusing binary and decimal units , and realize that the free space that df reports on an empty disk is a few percent smaller than the partition size, because there is administrative overhead.
If for a removable drive the kernel reports two different sizes, then one is found from the drive, and the other from the disk/floppy. This second value will be zero when the drive has no media.
Now, if you still think there are problems, or just are curious, read on.