About partition table

jacobselvin · 05-30-2006, 07:25 AM

Following is what I get as the output of fdisk -l. I have only one hard disk and have installed Windows XP and SUSE Linux. All these information can be clearly made with the following table.

Now I want to know why there is no sda3 and sda4? Why the partitions sda2 and sda5 starts at same cylender? Can anyone also recomment some good link where I can read some information about the partitioning?

Disk /dev/sda: 120.0 GB, 120033041920 bytes
255 heads, 63 sectors/track, 14593 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 3916 31455238+ 7 HPFS/NTFS
/dev/sda2 3917 14592 85754970 f W95 Ext'd (LBA)
/dev/sda5 3917 7832 31455238+ b W95 FAT32
/dev/sda6 7833 10443 20972826 b W95 FAT32
/dev/sda7 10444 14337 31278523+ 83 Linux
/dev/sda8 14338 14592 2048256 82 Linux swap / Solaris

Cheers.

cs-cam · 05-30-2006, 07:51 AM

A disk can only have 4 primary partitions. If you want more than 4 which to me is pointless but anywho... you can do so using logical partitions. There are akin to psuedo-partitions. In your case, it looks like sda2 is a logical partition containing sda5-8. You could create more primary partitions which would become sda3 & sda4.

michaelk · 05-30-2006, 07:51 AM

In a nutshell:
Primary partitions have IDs 1-4. In order to create more then 4 partitions on of the primary partitions is an extended partition ( Ext'd ). An extended partition is a container for logical partitions. Logical partitions are then created within the extended partition and have an ID >=5. You do not need to create all 4 primary partitions before creating an extended with logicals.

Just google for primary, extended and logical partitions.

jacobselvin · 05-30-2006, 11:51 PM

Thanks for the reply. I did some googling and got some valuable information. In one article I read that the boot loader can only load OSs located in primary partitions. In my case I have only one primary partition and linux is located in one of the logical partitions. I'm using GRUB as boot loader. I'm wondering how GRUB loads my linux although it's not in a primary partition?

detpenguin · 05-30-2006, 11:57 PM

Quote:

Originally Posted by jacobselvin

Thanks for the reply. I did some googling and got some valuable information. In one article I read that the boot loader can only load OSs located in primary partitions. In my case I have only one primary partition and linux is located in one of the logical partitions. I'm using GRUB as boot loader. I'm wondering how GRUB loads my linux although it's not in a primary partition?

you got some bad information there....i have 2 harddrives, and a nice collection of primary and logical partitions and a few linux os's loaded onto logical drives which boot just fine.

syg00 · 05-31-2006, 12:57 AM

Quote:

Originally Posted by jacobselvin

In one article I read that the boot loader can only load OSs located in primary partitions.

This is true for brain-dead loaders.
The only one of which you are likely to encounters is M$ofts.

All Linux loaders don't suffer from this restriction. Unfortunately a lot of the articles on various web sites is very M$oft specific - and the authors don't even know that other options exist..

cs-cam · 05-31-2006, 09:11 AM

Quote:

The only one of which you are likely to encounters is M$ofts.

Or the FreeBSD LOADER

Emerson · 05-31-2006, 09:19 AM

Quote:

Originally Posted by cs-cam

Or the FreeBSD LOADER

Well, it _can_ load FBSD when disk is configured in DD (dangerously dedicated) mode. Any other configuration and it looks more like a joke ...

davcefai · 05-31-2006, 11:52 AM

It's actually worse than this. Given a system with 2 SATA drives and you want to install Win2K on sdb1, when you try this the installer wants to write files to sda1. Since the partition is "not writable" (no Bill, it's ext3 formatted) the installer recommends that you format sda1.

(Solution, connect the drive to the first SATA channel, install as normal, revert to previous setup and lilo will happily lie to Windows and get it to boot.)

haertig · 05-31-2006, 10:24 PM

Quote:

Originally Posted by syg00

This is true for brain-dead loaders.
The only one of which you are likely to encounters is M$ofts.

Believe it or not, even Windows can be booted out of a logical partition. I've got one system doing this with W2k now. But you need a third party boot manager to invoke the Windows bootloader (I use XOSL, but I'm sure Grub or Lilo would work too). You also have to manually hack the Windows logical partition boot record (partitions have boot records, just like disks have master boot records). You also have to work around Window's refusal to install itself to a logical partition (the solution is to install it to a primary, then clone it up to a logical afterwards). A real pain in the butt ... but it CAN be done!

Linux is SOOOO much easier though! It cares not whether it's in a primary or a logical, or a mixture, or scattered about various HDD's via LVM. SOOOOO much better!