[CALUG] Disk alignment and boundaries -- WAS: Fedora upgrade

[Bryan J Smith]

Pretty much all disks today come pre-sliced with the first 1MiB (0-2047 for 
512b, 0-255 for 4KiB sectors) being reserved for MBR and the first slice 
starting after that 1MiB (at sector 2048 for 512b, 256 for 4KiB).

Slices do not need to start on a cylinder boundary.  That was an old DOS 
(including DOS 7 aka 95/98/Me) limitation that NT has never had (at least not 
since before NT4 SP4), and Linux has never, ever required AFAIK (maybe back 
before 2.0, never tried it with 1.3 or even old 0.96 when I first started with 
SLS and Yggdrassil).  CHS can safely be _ignored_ with NT and Linux.

Logical partitions require a reservation for the Extended meta-data, hence the 
offset and not at 0.  Don't know what you mean by 16065.  Again, CHS can be 
safely _ignored_ with NT and Linux.  It was only a requirement for DOS.  CHS is 
distracting.

________________________________
From: James Ewing Cottrell 3rd <JECottrell3 at Comcast.NET>
Sent: Mon, June 20, 2011 4:26:02 PM

I was gonna ask what stars too. Yes, the '+' means that you have an     odd 
sector.

I suppose the newer fdisks may deal directly in sectors rather than     
cylinders, but remember that Primary Partition 1 shares space with     the MBR, 
and the first track of the disk is reserved as a Boot Code     Extension, so 
we're not totally away from CHS yet. Primary     Partitions [234] start at a 
Cylinder Boundary. I always start my     P1's ar Cylinder 2 so that they are the 

same size as P[234] as long     as they have the same number of cylinders.

Logical Partitions are not handled correctly in fdisk...use the x     command 
followed by the p command and see that the Start offset of     all but the first 

LP is 63 rather than 16065. Disk Druid et al will     fix this for you during 
installation, but you are on your own later.