LBA mode was: Re: [TCLUG:17648] Moving the install & Linux fdisk 20gb IDE drive h*ll

["Carl Wilhelm Soderstrom" <carls@agritech.com>]

>I'm not so sure that LBA is a kludge.  AFAIK, LBA has
>_always_ been used w/ SCSI disks.  
        
no, LBA is IDE-specific. SCSI never had the problems with accessing large
numbers of cylinders, that IDE did. (SCSI was done right in the first place...)

>Also, I think that
>LBA came about when drives reached about 504(?)MB in
>size (which is before Windows 95).  
        
        512MB, I belive. 
        perhaps it was a kludge for DOS or win3; or a BIOS issue. (my
knowlege fails at this point).

>LBA is, AFAIK, more
>efficient than normal (which is probably ECHS "large")
>disk support.
        I do not know anything about efficiency. considering that it reduces
the number of cylinders; could it improve seek time? however, it increases
the apparent number of heads; so could that difference between real and
virtual heads cause a degradation in performance over long reads on a
fragmented filesystem?
        BIOSes I've seen, have options for 'normal', 'large', and 'LBA'
modes. I do not know what the difference between 'normal' and 'large' is.

>I've never had any problems with Linux accessing any of
>my LBA drives.  Make sure you have INT13 extensions
>turned on in your BIOS (you do have them turned on, don't
>you?)
        what are INT13 extensions? 

I don't claim to be right or to know much; I'm trying to learn this stuff as
much as everyone else. :)

Carl Soderstrom
System Administrator    307 Brighton Ave. 
Minnesota DHIA	        Buffalo, MN	
carls@agritech.com      (763) 682-1091