I have a 2nd hard-drive with 2 paritions.
[/dev/hdb]
[hdb1=partition 1; hdb2=partition 2]

when I run fdisk /dev/hdb and [p]rint I get this:
-------------------------------------------------
Disk /dev/hdb: 2111 MB, 2111864832 bytes
16 heads, 63 sectors/track, 4092 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

Device Boot Start End Blocks Id System
/dev/hdb1 1 1985 999969 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/hdb2 1985 4092 1062367+ 83 Linux
Partition 2 does not end on cylinder boundary.
-------------------------------------------------

My first hard-drive shows:
-------------------------------------------------
Disk /dev/hda: 20.4 GB, 20496236544 bytes
255 heads, 63 sectors/track, 2491 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hda1 * 1 1356 10892038+ c W95 FAT32 (LBA)
/dev/hda2 1408 2491 8707230 83 Linux
/dev/hda3 1357 1407 409657+ 82 Linux swap / Solaris
-------------------------------------------------


Both hard-drives are certified as 20GB and no bad sectors.
But why does the 2nd hard-drive show as only 2111MB (about 10% of what it should show).


I can see that the heads and cylinder info is different on both these devices; I have tried to make the 2nd hard-drive the same as the first i.e.
255 heads, 63 sectors/track, 2491 cylinders
using:
fdisk [-C cyls] [-H heads] [-S sects] device
but the 2nd hard-drive still shows as:
16 heads, 63 sectors/track, 4092 cylinders

How do get the rest of the 20GB to show on my system?


I'm using 'Mandriva2006 Free edition'
1GHz/256MBRAM/2x20GB HDD/400MBSwap

Post the make model number the hdb drive. From the output of dmesg command
dmesg | grep hdb

If you put commas in there, I think your drive is actually a 2G drive, not a 20G drive.

/dev/hda = 20,496,236,544 = a 20G drive
/dev/hdb = 2,111,864,832 = a 2G drive

Regardless of what the 'certificate' might say, from what you've listed, you got one 20G drive and one 2G drive. If this is a recent purchase, I'd confront the seller.

Additionally, as michaelk indicated, can you provide the exact make/model number of both drives?

MichaelK, Here is the output from dmesg |grep hdb: ------------------------------------------------------ ide0: BM-DMA at 0x2400-0x2407, BIOS settings: hdaMA, hdbMA hdb: QUANTUM FIREBALLlct20 20, ATA DISK drive hdb: max request size: 128KiB hdb: 4124736 sectors (2111 MB) w/418KiB Cache, CHS=4092/16/63, UDMA(33) hdb: cache flushes not supported ------------------------------------------------------

This is the output from dmesg | grep hda
------------------------------------------------------
Kernel command line: BOOT_IMAGE=Linux_Mandriva2006_(hda2) root=302
ide0: BM-DMA at 0x2400-0x2407, BIOS settings: hdaMA, hdbMA
hda: FUJITSU MPG3204AH E, ATA DISK drive
hda: max request size: 128KiB
hda: 40031712 sectors (20496 MB) w/2048KiB Cache, CHS=39714/16/63, UDMA(100)
hda: cache flushes not supported
EXT3 FS on hda2, internal journal
Adding 409648k swap on /dev/hda3. Priority:-1 extents:1
------------------------------------------------------


J.W., I too have considered that it is only a 2GB Hard-drive but I have used fdisk in MS-DOS that comes with Win98 startup floppy and I have mounted the drive as [d:], formatted it as filesystem type FAT32. This then shows as 20GB. I did have Win98SE on this device previously then a full install of Mandriva2006 Free Edition; it is definitely a 20GB Hdd. I then formatted the drive to custom install Mandriva2006FE, but during disk druid it only showed as 1.9GB~2.1GB as filesytem ext3. Any suggestions?

According to some info found on the web Fireball LCT20s came in 4 different sizes,
10, 20, 30 & 40GB. So this could be a 20GB drive but the numbers do not match. The cylinders should be 16383 and not 4092.

You can read the info from the hard drive via the hdparm command i.e.
hdparm -i /dev/hdb. This should be the same thing read at boot i.e what you saw via the dmesg command.

I've tried to change the number cylinders using FDISK in Mandriva2006 but although I'm [w]riting the info to disk and then reboot (as advised by FDISK; as the kernel reads the old hard-disk info prior to writing). System reboots again and I check the hard-disk info again with "fdisk /dev/hba" then [p]rint and still the cylinders are 4092. Also repeated this and tried to change the number of heads but exactley the same happens as mentioned in this paragraph.

The only way round this problem I can see is to format the drive under MS DOS as FAT32 then simply mount the device in my /etc/fstab file. Only thing, I don't really want to be using FAT32, as I prefer ext3 filesytem.

I would say it's likely MS-DOS caused the problem - it's one of the (few) things that uses CHS to the exclusion of LBA.

If it were me, I'd simply zero the first sector, to ensure there was no "old" partition data left, and simply fdisk it from Linux.
Might even be worth doing the entire disk, although that takes a while.

My experience has always been that Linux (once booted) always ignores the BIOS.

That would fit well - I had a full install of Mandriva2006 then formatted the hard-disk and replaced with win98se - boy am I regretting that one. Just tried to format the hard disk under MS DOS but now I'm getting the error:

Format terminated, cannot write 'BOOT'

Syg00, with regards to your second comment; how do I zero the first sector to ensure that is no 'old' partition?

You can use the dd command to zero the boot sector.
dd if=/dev/zero of=/dev/dev/hda bs=512 count=1
(change /dev/hda to match the actual device ID. Be carefull to enter the correct device)

Most drive manufactures have a diagnostics utility then you can download from their website to checkout the drive for errors. Typically they are a MSDOS floppy disk utility.

Make that "of=/dev/hdb" and you should be right to go.
On occasions it is also necessary to trash previous filesystems when new partitions align to the start of an old one (e.g. first partition on disk).

Use same command with hdb? and a count of say 20 should this be needed.