Re: Partition table confusion
----- Original Message -----
From: Steve Dondley <s@dondley.com>
To: Debian User List <debian-user@lists.debian.org>
Sent: Saturday, August 17, 2002 1:42 AM
Subject: Partition table confusion
> Hi,
>
> I'm trying to learn as much as possible about the logical structures
on a
> hard disk. I was looking at cfdisk's printout of my partition table
and I'm
> a little confused by it:
>
>
> ---Starting--- ----Ending---- Start Number of
> # Flags Head Sect Cyl ID Head Sect Cyl Sector Sectors
> -- ----- ---- ---- ---- ---- ---- ---- ---- -------- ---------
> 1 0x80 1 1 0 0x83 239 63 1023 63 19867617
> 2 0x00 239 63 1023 0x05 239 63 1023 19867680 136080
> 3 0x00 0 0 0 0x00 0 0 0 0 0
> 4 0x00 0 0 0 0x00 0 0 0 0 0
> 5 0x00 239 63 1023 0x82 239 63 1023 63 136017
>
>
> Based on the ID field, Entry #1 is the regular linux partition and
entry #2
> is the swap partition. My questions are:
>
> What is Entry #2? It's ID is 05 which is an extended DOS partition.
> However, when I set up my hard drive, I never created this partition.
How
> did it get there?
>
> How can partition #2 and partition #5 share the same start and end
h,s,c
> number yet have such different start sectors (I'm assuming the
19867680 is
> LBA)?
>
> I thought partition tables could only have 4 entries. This table
shows 5.
> Why?
>
> Any insight on these questions is greatly appreciated.
>
Partition 5 is your swap partition which is a logical partition within
the extended partition (2).
Partition 5 is counting its sectors not from the start of the disk but
from the start of partition 2. That's why it has start sector 63 and
number of sectors 63 less than partition 2.
Logical and extended partitions are a way around the 4-partition
limitation. Extended partitions can have up to 4 logical partitions in
them. AFAIK you can have more extended partitions as logical partitions
within extended partitions so in theory you can have a more or less
unlimited number of partitions, though why you would want to is another
matter.
As to how your disk got set up that way I have no idea. All I can say is
mine didn't! - I used the standard setup procedure on the Debian CD-ROM
and got the partitions I wanted.
Pigeon
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