partmap 15 limit

[Steve Ward]

I just experienced the 15 partition limit in the most recent install of YDL
3.0. When I had more than 15 partitions the installation always went
sideways; but as soon as I reduced my partition count, things went
swimmingly.
So much for the myth... ;)
Steve

on 6/4/04 7:27 AM, Geert Janssens at geert.janssens3@pandora.be wrote:

> I have never seen two separate partitions next to one another as free.
> When I free a partition with pdisk, it is always merged automatically
> with the adjacent free partition. Have you been using a macos
> partitioner ? In any case, I believe partition 9 and 10 could form 1
> free block. The other free blocks can only be merged by relocating the
> partitions in between.
> 
> I don't know a particular tool that does this with a single click of the
> mouse. The manual way involves creating new partitions and copying all
> data from the old to the new partition, all while ensuring that the
> operating system in question can keep track of which partition has moved
> where. I know how to do this in Linux, I have relocated my root
> partition several times because of disk space limitations, as well as my
> home partition. I don't know how I should go about performing the same
> task under OS X though (I never got further than mac os 9).
> 
> 
> On a related note, it may be interesting to know that the 15 partitions
> limit is an old myth by now. I all has to do with the availability of
> the right device files in /dev. It used to be that several popular Linux
> distributions only provided 15 such device files for each possible hard
> disk.
> 
> For example, for the first hard disk (on a IDE based system), you had
> /dev/hda1 up until /dev/hda15. The kernel uses these device files to
> access a partition on that disk:
> /dev/hda1 is used to access the first partition,
> /dev/hda2 for the second, and so on.
> 
> Or if there are less than 15 partitions, the device files for which
> there is no corresponding partition point to nothing. The kernel simply
> gives an error if you try to use them.
> 
> Having more partitions than device files for a given disk is more of a
> problem, because without a device file, the kernel has no way to access
> the corresponding partition.
> 
> But, don't panic just yet. I see in my /dev directory that YDL 3.0
> apparently provides for 32 partitions per disk, so in your situation,
> you don't have to worry yet.
> 
> Should you happen to come one day to the point that you have more than
> 32 partitions, then with the mknod command you can create more device
> files, up until 63 per disk. To understand mknod, see man mknod and also
> read file /usr/src/linux/Documentation/devices.txt. The latter is only
> available if you have installed the kernel sources.
> 
> So, what linux is concerned, the sky is the limit :-)
> 
> On afterthought, I don't know how well OsX handles more than 15
> partitions and in particular, how well it handles when one of it's own
> partitions (be it system or data) is beyond 15. Anyone else has info on
> this ?
> 
> Hope this helps.
> 
> Cheers,
> Geert
> 
> mascarasnake wrote:
>> Just a quick question.
>> I've been following the 15 partition thread for a while now. I've
>> reformatted my main drive now in several different ways and keep getting
>> extraneous free parts that will take me above the 15 part limit.
>> 
>> thinking about YDL 4 on this machine
>> 
>> I'm running 10.3.4 on a B&W G3 rev2, all disks running on the internal
>> ATA bus(s)
>> 
>> here's my part map for the drive I want to install YDL 4 on:
>> 
>> 1:  Apple_partition_map Apple                     63 @ 1
>> 2:       Apple_Driver43*Macintosh                 56 @ 64
>> 3:       Apple_Driver43*Macintosh                 56 @ 120
>> 4:     Apple_Driver_ATA*Macintosh                 56 @ 176
>> 5:     Apple_Driver_ATA*Macintosh                 56 @ 232
>> 6:       Apple_FWDriver Macintosh                512 @ 288
>> 7:   Apple_Driver_IOKit Macintosh                512 @ 800
>> 8:        Apple_Patches Patch Partition          512 @ 1312
>> 9:           Apple_Free                     19369792 @ 1824      ( 9.2G)
>> 10:           Apple_Free                            0+@ 19371616
>> 11:            Apple_HFS Apple_HFS_Untitled_3  41680896 @ 19633760  (
>> 19.9G)
>> 12:           Apple_Free                            0+@ 61314656
>> 13:            Apple_HFS Apple_HFS_Untitled_4   6029312 @ 61576800  (
>> 2.9G)
>> 14:           Apple_Free                            0+@ 67606112
>> 15:            Apple_HFS Apple_HFS_Untitled_5  88499744 @ 67868256  (
>> 42.2G)
>> 16:           Apple_Free                            0+@ 156368000
>> 
>> my question is can I combine the empty (9, 10, 12, 14, and 16) without
>> killing it all?
>> 
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