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>6. Partition Naming in Linux</H1
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>6.1. Numbers</H2
><P
>Partition naming is thanksfully simpler than drive one.
Partitions are simply given a number from 0 up (decimal).
Sometime a "p" is appended on front of the number:</P
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>&#13; cat /proc/partitions
major minor #blocks name
8 0 488386584 sda
8 1 52436128 sda1
8 2 1 sda2
8 5 2104483 sda5
8 6 20972826 sda6
8 7 52436128 sda7
8 8 360434308 sda8
179 0 3979776 mmcblk0
179 1 3975680 mmcblk0p1
</PRE
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><P
>As you see, partition devices are listed in
/proc/partition. This file... is not a real file but is
created on the fly. Don't worry, for what we need it's a
file.</P
><P
>Notice the "p1" partition name for the SDHC
card.</P
><P
>Max number of partitions is 15 for SCSI and all the
drives using the new SATA driver, 63 for IDE drives (0 is the
full drive, 0 to 15 is four bits 0 to 64, 6 bits)</P
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>6.2. Meaning of the Numbers</H2
><P
>Not all the numbers have the same meaning. This mess
come from the PC history. One can divide floppies with
partitions, but then 4 ones seems sufficient. But then come
Hard drives :-). So the partitons numbers 1, 2, 3 and 4 are
<EM
>primary</EM
>partitions. One drive can only
have 4 primaries.</P
><P
>To go further, we have to use one of these primary as a
big one and sub-partition this one, so to have
<EM
>logical</EM
>partitions. The big
<EM
>extended</EM
>partition can be any of the
4.</P
><P
>So, remember, the primary partitions are inside the
drive and the logical partitions are inside one of the
primary, called the
<EM
>extended</EM
>partition.</P
><P
>Once the logical partitions are created, it's no more
recommended to write directly to the extended one. Writing to
an extended partition would erase the logical ones like
writing directly to a hard drive erase the partitons. Beware,
<STRONG
>it's possible</STRONG
>!!</P
><P
>If, after creating 4 primary partitions, all the disk
space is not used, the remaining space is lost (unusable), so
most of the time, create the desired primaries, then at last
the extended one with all the remaining room.</P
><P
>It's not necessary to create 4 primaries. You could use
only one extended (Linux only), but there are some advantages
of using primaries.</P
><P
>Primaries being 4, the first logical partition is
always 5. So any partition with number of five and up is a
logical one.</P
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