Gregory Hosler <ghosler <at> redhat.com> writes:
...
Hi,
FYI. This is from the dev team member.
From: Karel Zak <kzak@...>
Subject: Re: cfdisk - logical partition
Newsgroups: gmane.linux.utilities.util-linux-ng
Date: 2010-08-06 13:18:37 GMT (35 minutes ago)
On Fri, Aug 06, 2010 at 01:26:27PM +0200, J B wrote:
Example 1.
==========
The last item (Free space) is "logical"
Logical 192425984* 192426569 0 586*Free Space
None
but clearly outside of extended partition's range.
This is feature. The free space around extended partition is always
marked as logical if the number of all partitions is greater than 4
(it means you cannot create a primary partition).
Don't forget that cfdisk allows to create logical or primary
partitions only. The extended partition is created/modified
automatically for all logical partitions. The extended partition is
completely hidden in the default output (interactive mode).
4 Primary 105076736* 192425983* 0 87349248*Extended (05)
None
Should it be "None" like the Unusable partition between 3 and 2 ?
I don't think so.
Is that space mapped ("logical") or not ?
cfdisk is able to use the free space for logical partitions only.
From partition table point of view the space is invisible.
Will an installer (e.g. anaconda which uses parted) know about it ?
I don't know (try to use parted, you will see) ... it depends on
libparted. I think that smart partitioning tool should be able to
detect gaps in layout and reuse the free space.
> Example 2.
> ==========
> One more "rule to follow" with regard to partitions:
>
http://www.lissot.net/partition/partition-03.html
...
> Unlike primary partitions, logical partitions must be
contiguous.
> Each logical partition contains a pointer to the next logical partition, ...
>
> Between partitions 2 and 4 there is a free space marked as "logical".
>
> Logical 219463964* 219463964 0 1*Free Space
> None
>
> It is clearly outside of the Extended partition range.
that's the same situation like in your Example 1.
How comes it is called "logical" if it violates the rule of
contiguousness ?
No, cfdisk will update the first sector of the extended partition if
you create a logical partition from the free space. The final ext
partition will be contiguous.
# cfdisk -Ps
Partition Table for /dev/sda
First Last
# Type Sector Sector Offset Length Filesystem Type (ID)
Flag
-- ------- ----------- ----------- ------ ----------- -------------------- ----
1 Primary 0 128519 63 128520 Dell Utility (DE)
None
2 Primary 128520 219463963* 0 219335444*HPFS/NTFS (07)
Boot
Logical 219463964* 219463964 0 1*Free Space
None
4 Primary 219463965 615401954 0 395937990 W95 Ext'd (LBA) (0F)
None
5 Logical 219463965 223672994 63 4209030 Linux swap / So (82)
None
6 Logical 223672995 265618709 63 41945715 Linux (83)
Boot
7 Logical 265618710 615401954 63 349783245 Linux (83)
None
3 Primary 615401955 625137344 0 9735390 CP/M / CTOS / . (DB)
None
Example 3.
==========
This example is by Michael Schwendt <mschwendt <at> gmail.com> .
These are his comments.
You might want to examine the cfdisk source code to find out. cfdisk does
not claim it would be a valid partition. It just prints a partition type
for the free space, and that already could be a bug. Happens here, too:
First Last
# Type Sector Sector Offset Length Filesystem Type (ID) Flag
-- ------- ----------- ----------- ------ ----------- -------------------- ----
1 Primary 0 390625* 1# 390626*Linux
(83) Boot
2 Primary 390626* 781250* 0 390625*Linux
(83) None
3 Primary 781251* 39062500* 0 38281250*Linux
(83) None
Logical 39062501* 39070079 0 7579*Free
Space None
this is correct, you cannot create a primary partition (all positions
are used) and the space is possible to add to the existing extended
partition (part 4.)
4 Primary 39070080 976768064 0 937697985 W95 Ext'd
(LBA) (0F) None
5 Logical 39070080 78124094 63 39054015 Linux
(83) None
6 Logical 78124095 117194174 63 39070080 Linux
(83) None
7 Logical 117194175 156248189 63 39054015 Linux (83)
None
8 Logical 156248190 195318269 63 39070080 Linux (83) None
9 Logical 195318270 203125859 63 7807590 Linux swap / So (82) None
10 Logical 203125860 976768064 63 773642205 Linux LVM
(8E) None
Karel
--
Karel Zak <kzak@...>
http://karelzak.blogspot.com
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