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**oshunluvr** · Jul 06, 2011, 09:22 AM

Re: A strange result from "gparted" ?

Look to me like /dev/sda is partitioned with 1 primary partition (sda1) and it's an Extended partition.
Partitions 5-8 are Logical partitions within sda1. Numbers 1-4 are reserved for primary partitions.

Looks normal to me unless you didn't intend to format this way. This isn't a problem for linux, but you can't install winblows to a Logical partition.

**Qqmike** · Jul 06, 2011, 10:40 AM

Re: A strange result from "gparted" ?

Yeah, it'll probably work just fine. Couple comments:

OK, I see you switched to
ubuntu@ubuntu:~$ sudo fdisk -lu
instead of
ubuntu@ubuntu:~$ sudo fdisk -l
and that's good (u = 512 is nice to see).

sudo dd if=/dev/sda of=whatsthis bs=512 skip=63 count=126
actually can just be
sudo dd if=/dev/sda of=whatsthis bs=512 skip=63 count=63

but that's not an issue here. Anyway, it looks like it's all zeros, from what you said.
- - - - -

It's OK to make the extended partition = the whole disk (a little unusual for some users, but OK).

It looks like gparted "viewed" sda5 the way it views a disk--it allotted the standard LBA 63 sectors for the MBR. But note that it did the same thing to the other partitions, starting each one after a gap of (about) 63 sectors. Usually if a partition ends at sector N, the next one starts at sector N+1.
- - - - -

If it were me, since you have a clean slate, just for the heck of it, I'd burn a new GParted Live CD (latest good version of it), and run it against that hard drive, partitioning it again.

**kubicle** · Jul 06, 2011, 11:25 AM

Re: A strange result from "gparted" ?

Originally posted by Qqmike

It looks like gparted "viewed" sda5 the way it views a disk--it allotted the standard LBA 63 sectors for the MBR. But note that it did the same thing to the other partitions, starting each one after a gap of (about) 63 sectors. Usually if a partition ends at sector N, the next one starts at sector N+1.

The "gaps" are the EBRs of those logical partitions (primary partitions don't have them, as the info is stored in MBR)

**kubicle** · Jul 06, 2011, 11:26 AM

Re: A strange result from "gparted" ?

Oops...double post

**Qqmike** · Jul 06, 2011, 12:14 PM

Re: A strange result from "gparted" ?

kubicle, Ah yes! Those EBRs! I'm a bit rusty, I'm afraid. Thanks.

**Qqmike** · Jul 06, 2011, 12:19 PM

Re: A strange result from "gparted" ?

That's right. So (of course!) my N -> N + 1 rule does not apply to partitions embedded in an extended partition because of the succeeding EBR. In his case, ALL partitions are so embedded.

**oshunluvr** · Jul 06, 2011, 09:40 PM

Re: A strange result from "gparted" ?

If you guys keep going, this might be considered a thread hijack... lol

**perspectoff** · Jul 13, 2011, 01:13 PM

Re: A strange result from "gparted" ?

Originally posted by oshunluvr

Look to me like /dev/sda is partitioned with 1 primary partition (sda1) and it's an Extended partition.
Partitions 5-8 are Logical partitions within sda1. Numbers 1-4 are reserved for primary partitions.

The MS-DOS partitioning scheme allows 4 main partitions:

4 primaries

or

3 primaries and 1 extended

There is no reservation of the first 4 as primaries, and an extended partition can be any of the first 4. In the past Windows only booted from the first partition, but not any longer. Windows can boot from any primary partition, and now that Windows 7 uses its own boot partition, possibly (I'm not an advanced Windows user so don't quote me) Windows 7 can even be booted from an extended partition as long as the Windows boot partition (with bootloader) remains on a primary partition.

The only time I've seen an extended partition on /dev/sda5 is when there were initially 4 primary partitions, one of them (either sda2 or sda3) was deleted and an extended partition created from the resulting free space (and therefore became denoted as sda5).

This isn't particularly problematic, and the observation that the size of the extended partition should be the same as the sum of the logical partitions within it is, of course, correct.

My 2010 (and older) versions of GParted LiveCD screwed up my superblock tags (or something like that) and made some of my partitions unreadable when moving/resizing them. It think there has been a change in the way ext4 filesystem handles superblocks and embedded blocks, and the older versions don't get it right, or something of that nature.

I now rely solely on the version of GParted that comes on the Ubuntu Natty LiveCD.

**oshunluvr** · Jul 13, 2011, 10:07 PM

Re: A strange result from "gparted" ?

There is no reservation of the first 4 as primaries,

Sorry, but you're wrong - at least as far as any partitioning scheme I've ever heard of goes. Device numbers 1 through 4 are reserved, period. 1 of those may be an Extended partition as you said but that doesn't change the numbering scheme. Using the word "main" or I've even read "customary" (Microsoft uses the word "standard") to replace the word primary doesn't change this fact. regardless of which primary partition is designated as an Extended partition, the Logical partition numbering begins at 5 - you need look no further than the original post to see a clear example of this.

I would be very interested to see the partition table of a drive with an Extended partition as /dev/sda5 or a Logical partition as dev/sda1, 2, 3, or 4.

**perspectoff** · Jul 15, 2011, 07:14 PM

Re: A strange result from "gparted" ?

Nonsense.

**Snowhog** · Jul 16, 2011, 06:15 PM

Re: A strange result from "gparted" ?

Not nonsense.

Yes, you can create an extendend partition as the fist partition on a HDD. But, it will not be identified as sda1, it will be sda5. The first four partitions on any HDD are 'reserved' for use as primaries, of which you can only have four. If you create four primary partitions, you can not create any additional partitions.

**oshunluvr** · Jul 16, 2011, 07:37 PM

Re: A strange result from "gparted" ?

I suspect you're wasting your time Snowhog.

**Snowhog** · Jul 16, 2011, 08:46 PM

Re: A strange result from "gparted" ?

Difference Between Primary Partition and Logical Partition

What is Primary Partition?

A disk drive can contain a maximum of four primary partitions or three primary partitions and a single extended partition.

**kubicle** · Jul 17, 2011, 12:31 AM

Re: A strange result from "gparted" ?

Originally posted by Snowhog

Yes, you can create an extendend partition as the fist partition on a HDD. But, it will not be identified as sda1, it will be sda5. The first four partitions on any HDD are 'reserved' for use as primaries, of which you can only have four. If you create four primary partitions, you can not create any additional partitions.

The extended partition will always have a number between 1-4 (it takes the "place" of one primary partition), but the logical partitions created within the extended partition always start from 5. And the logical partitions are the ones that contain the file systems. In the first post on this thread you can see the extended partition is sda1, and the four logical partitions are sda5-8.

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