Re: tlug: Sun disk label fdisk/SCSI question

[Scott Stone <sstone@example.com>]

On Wed, 10 Jun 1998, Rex Walters wrote:

> On Wed, Jun 10, 1998 at 03:53:42PM +0900, Scott Stone wrote:
> >                                                                       The
> > reason why the 64head/32cyl mapping exists is because without it, programs
>                           ^^^
> 			  s/b sectors-per-track, not "cyl"
> 
> > that use the BIOS for disk geometry (ie, LILO, MS-DOS, Win95) can't see
> > more than about 500 megs of the disk.
> 
> Malarky.  
> 
> 1 MB per cylinder is purely for human simplicity.  PC BIOS's gag on
> anything more than 1024 cylinders ("Gee, Joe, 10 bits should be enough
> *forever*, dontcha think?" ;-).  If you need to access disks bigger than 1
> GB with BIOS, you can't use 64/32 (at least, not if you need to access
> all of your disk).  
> 
> 1024 cylinders with 64 heads and 32 sectors-per-track (and 512 bytes per
> sector, of course) works out to only 1 GB.  If you've got something
> bigger, and you must use BIOS (poor soul) you need to increase "h" or
> "s" accordingly.

ah, I see.  I think I was confused, so I was thinking that we were
discussing what LBA does, which i guess we werent.  LBA, of course, is the
new 'hack' for PC bioses to remap big drives to <= 1024cyl.  Although, it
does work, so I guess it's not so much of a hack.

Ick, I'm rambling.  sorry.

--------------------------------------------------
Scott M. Stone <sstone@example.com, sstone@example.com>
               <sstone@example.com>
Linux Developer/Systems Administrator for Pacific HiTech, Inc. 
http://www.pht.com		http://armadillo.pht.co.jp
http://www.pht.co.jp	        http://www.turbolinux.com


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