On Sat, 10 Nov 2012 16:09:36 -0600 Charles Blair <c-bl...@illinois.edu> wrote:
> I am trying to set up a dual-boot windows 7 / wheezy. > > The installer shows me 3 primary ntfs partitions, > presumably for windows7. > > I have been able to resize to create freespace. > As I understand it, / must be bootable, which seems > to mean it must be a primary partition. However, > when I do that, the installer shows the remaining > free space as "unusable," and won't let me create > logical partitions for swap, /usr, etc. > > I'm sure I'm overlooking something basic. Thanks > for your patient help. > > As others have said, up to four primary partitions, OR one extended partition and up to three primaries. The difference between them is that only four slots are allocated for partitions in the table: IBM apparently thought that nobody would ever need more than four. The 'extended' partition is an entry in the four slot table pointing to another disc area where more partition table entries can be placed. There's little agreement on how many are 'enough' these days, and an OS will often permit more on a SCSI drive than an ATA. You can usually bet on at least ten 'logical' partitions being available. There is no practical difference between primary and logical partition usage *except* that Windows (up to and including XP to my knowledge, probably later versions also) requires that the first primary partition it can recognise (i.e. the partition table says it's FAT or NTFS) must be marked with the 'bootable' flag, and must contain a few critical boot files. Apart from that, anything can be anywhere, including the Windows directory which contains the entire OS apart from the boot files. Linux does not make use of the 'bootable' flag, though Linux partitioning utilities can set and display it. Linux does not need anything to be stored on a primary partition. By the way, one or possibly two of the NTFS partitions will not normally be used, they are usually a recovery partition (MS hasn't supplied installation media for many years) and the computer manufacturer's rescue tools and drivers. Windows itself normally only uses one partition on consumer OEM computers. If that is indeed the case, they can be copied off elsewhere (with a note of their partition table entries) and the space used, and can be copied back to the same physical disc locations if you ever need to reinstall Windows. Don't try moving Windows itself (though its partition can usually be shrunk) because some of the OS knows where it is, on which individual hard drive, and assumes that if it's not there it's an illegal copy, and will refuse to run. Note that the partition table is completely separate from the rest of the drive. The first thing you ever do when messing with partitions is to write all the numbers down or print it. Then, if you make a complete mess of the table, so long as you haven't mounted anything and written to it, you can often use a rescue disc to rewrite the partition table exactly as it was, and restore things. Just don't bet irreplaceable files on that principle, because the one day you are out of luck will be that day... -- Joe -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20121111102510.2a604...@jretrading.com
