Messages in this thread |  | | | Date | Mon, 06 Nov 2006 01:36:09 +0100 | | From | Rene Herman <> | | Subject | Re: New filesystem for Linux |
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H. Peter Anvin wrote:
> Rene Herman wrote:
>> For primary (and extended) partitions, yes. I haven't used any version >> of DOS that has ever objected to arbitrarily aligned partitions in the >> MBR (and I do align them arbitrarily since I always make my partitions >> some exact size and start the next partition in the next sector). >> >> Different though for logical partitions inside an extended. As late as >> Windows 98, DOS would object to non-aligned logicals, at the very >> least with some settings for the BIOS use/don't use LBA or "Large" >> settings. >> >> Linux doesn't care; I've used type 0x85 instead of 0x05 for my >> extended partitions dus to that for years. DOS just ignores that one... >> > > DOS, or FDISK?
DOS. It was something like DOS accepting the non cylinder-aligned logical but then proceding as if it were cylinder aligned anyway, rounding the starting sector down. This obviously is not good.
Also see the "--DOS-extended" comment in the sfdisk man page. Since I do remember differences when using different "Large" CHSs in the BIOS, for all I remember I was experiencing that problem when I ran into it. If so, the DOS underlying Windows 98 is among the "some versions".
In any case, yes, non-cylinder aligned logical partitions (for whichever defintion of "aligned" fits DOS' idea of the geometry) really do cause trouble.
The DR-DOS (-> Novel DOS -> Caldera OpenDOS) warning in that manpage seems to imply that cylinder alignment was a good idea for all partitions seen by it, and I do remember it being a pain in that regard as well. Guess it's pretty safe to not care about DR-DOS anymore though.
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