partmap 15 limit

Sat Jun 5 13:59:01 2004

Intresting... there are a number of possible theories.

Could it be that the YDL installer himself is not capable of handling 
more than 15 partitions, although it installs device files for more ?

Or are there only 15 device files in your installation per disk ?

Maybe it also depends on the kind of installation chosen. Mine was a 
complete workstation. Perhaps a home/office installation allocates less 
device files.

Anyway, as myths go, there seems to be a core of truth behind this one. :-)

Cheers,

Geert

Steve Ward wrote:
> 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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