The Honest Truth About IDE Hard Disk Drives

Ok, here's the lowdown on IDE drives - they're kind of like SCSI in the
logical layout of the disk and it parameters, so they can mimic the
storage of any drive type that isn't above the number of physical
formatted bytes on the drive.  Be sure to not go above the number of
bytes or horrible things can happen.  So simply select a drive type
that is equal to or less than the number of available formatted bytes
on the drive.  Don't worry about MFM or RLL, since the drive only cares 
about total storage available.  Just be sure to not go one byte over.  
Remeber what happened in "Gremlins?" -- just don't do it!  Also, don't
install the drive as type 1 and expect it to be anything other than a
10Mb drive.  It's not smart (or stupid as it were) to go out and hack
the host's CMOS and BIOS unit locations.  And Les is right about them
being RLL, but since they translate internally and are controllers unto
themselves, it's kindofa moot point.

Another issue is formatting.  Do not format the drive with anything
that will do a low-level format.  On most IDEs the LLformat is
sacrosanct, and nothing'll touch it, but some are less observant than
others.  You can really screw them up by formatting them.  Just do a
high level or a little 'surfing (but no low level) if it'll make you
feel better.

The drive is also strange in that the IDE can be either a master or a
slave drive.  The master designation is for either the only drive, or
the first of two IDE drives.  The slave designation is only for the
second of two drives.  Now the master is the brains of the bunch, and
will actually pass commands onto the slave for its operation.  The
master also performs diagnostics for both drives in the pair.  For
those of you that like mirroring under SFT, you might be seeing a
little problem here.  For if a mirrored pair crashes, the first thing
the OS does (after retrying) is to reset the controller.  This
initiates diags IF THE MASTER IS STILL ALIVE (if not the OS'll timeout
and crash, since the slave can't do anythign without the master) or if
the master is ok, the master will timeout looking for the slave and the
OS'll crash.  Bummer.

Also, there's a lot of differences between the drive vendors.  The best
drives I've seen have been the Maxtor, Imprimis, and Conner.  The
majority of the rest are Trouble (notice the capital "T").  In
addition, many of the drives will need a patched version of ELS-I
NetWare (the WDs especially) which I really don't trust.  My advice is
to stay away from ELS-I and make the jump to ELS-II.  Trust me.  It's
worth it.

But for ELS-II and Advanced, they're quite, quick, and of surprisingly
good value.  I've seen some very nice drives in the larger sizes (the
Maxtor LX-200A is just sweet!) and they're great for installations that
won't push the envelope (or their pocketbook).  But remember that they
are quirky (oh, and be sure to know how many ECC bytes your system BIOS
will expect, since these can transfer either four or seven.) and
somewhat different than what you're used to.  Good luck and have fun.