Mailinglist Archive: opensuse (2532 mails)

[Anders Johansson <ajh@xxxxxxxxxx>]

On Sunday 04 May 2008 20:45:00 jdd wrote:
> I friend of mine said yesterday that in case of *logical* partition (5
> and up) the file allocation table (superbloc?) of the partition is
> written on a sector, at the beginning of the partition

File allocation table? FAT???

Anyway, yes, the bitmap for allocated blocks (in ext*) and similar book 
keeping is a part of the file system, and as such stored in the partition 
itself.

The partition table is less than 500 bytes and couldn't possibly store all 
such information

> so the question:
>
> How exacltly do fdisk works.
>
> say I create one primary partition of 20Go, and the rest is extended.
>
> In the extended I write two logical partitions, then I *w* write the
> table.
>
> what is really written? only the MBR (sort of) partition table or is
> the allocation table of the partitons 5 and 6 written right now,
> overwriting may be some data??

Please stop using "allocation table" when talking about partitions. This isn't 
FAT

Yes, in a logocal partition, there is a new partition table created at the 
start of it. Again, the main partition table is less than 500 bytes large and 
can only cope with the 4 standard partitions. For logical partitions, more 
room is needed

> My friend say yes, some data is lost.

Which data, where? So far you have only talked about creating partitions, I'm 
not quite sure what you're overwriting

Yes, if the logical partition previously was a normal partition that contained 
data, then you will be overwriting part of it. Some sort of file system 
metadata, most likely

Anders
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