Re: [TCLUG:17673] LBA mode was: Re: [TCLUG:17648] Moving the install & Linuxfdisk 20gb IDE drive h*ll

[Callum Lerwick <lerwick@tcfreenet.org>]

> >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...)

LBA = Linear Block Addressing. No, not IDE specific though maybe the
name is, Yes, SCSI's done it right from the start...
 
> >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).

Large disk howto. Go read. ;)

> >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?

No, because you're not actually changing the disk. Just the way the
drive/BIOS tells the OS whats there. There isn't going to be any
performance differences.

>         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 think normal just leaves things as is, and large does CHS
transelation...

> >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. :)

Large Disk Howto...
http://metalab.unc.edu/mdw/HOWTO/Large-Disk-HOWTO.html

Hmmm, I haven't read this since before the 8.4gb limit. *study*