[svlug] Adding hardrive advice .,.

Rick Moen rick at linuxmafia.com
Tue Jul 10 21:40:02 PDT 2001


begin bill at billjonas.com (Bill Jonas) quotation:

> I hope that Rick Moen won't mind me referring to his FAQ, but he has a
> lot of information on the subject (geared more toward 486s than
> Pentiums, but very useful nonetheless)....

Not at all.  I'm flattered, sir.

begin dc000741 at hotmail.com (David Cornwell) quotation:

> I want to add a 30-40 gb disk. No SCSI, to expensive and it's not needed.
> [...]  Problem is I'm confused as to what I need?

Your priorities are not my business, but perhaps you won't mind a brief
moment of amusement that being so confused you can't proceed is perfectly 
OK as long as you're _saving money_.

> Everything for sale is an ATA disk.  The Gateway machine has EIDE from
> 1996, I don't think ATA was around then.

You might want to read my still-timely March 1996 article, "All about EIDE",
at http://linuxmafia.com/pub/hardware/eide.txt .  "EIDE" was just a
marketing term for a particular package of ATA pseudo-standards, created and
promoted by Western Digital in the early 1990s.  "Fast ATA" was another
such, promoted by Seagate's marketroids around the same time.  For that
matter, "IDE" is a slightly older, fluffy marketing term for systems built
around ATA (AT Attachment) technology.  The real underlying technology is
most accurately referred to as "ATA"[1] -- which has had a raft of
more-or-less compatible enhancements grafted onto it over the years.

Still confused?  OK, but at least you're saving money.  ;->

> So does it mean that plunking in an ATA disk in is ok?

You betcha.  More or less.  We'll get into that, below.

> The guy at techsupport says I only need an adapter if I want to modify my
> old BIOS, which will allow my Gateway to see the whole 30-40 GB disk.  Is
> this true?

You could very well hit that 33.8 GB ATA-drive / old-BIOS limit that Bill
Jonas (indirectly) referred to, in his link to the Large Disk HOWTO.  As the
HOWTO points out, you can jumper some ATA drives to lie to the BIOS,
claiming to be smaller than they really are.  You then presumably feed the 
_real_ drive size to the booting kernel via LILO "append" directives, or 
such.

Or, as Bill says, use a smaller disk to boot from, such that your antique
BIOS boot routine's (possible) inability to correctly deal with >33.8 GB
ATA disks isn't an issue.

> [The Gateway technical support guy] says that adding the ATA disk without
> an ATA adaptor means I'll have to make lots of 2 GB partitions.

Nope.  He seems to have in mind the limitations of the old Microsoft FAT16
filesystem, whose maximum cluster size and number of entries in the FAT
table jointly imposed a maximum partition size of 2 GB.  Starting around
MS-Windows98 and the MS-DOS v. 4.10.1998 version within it, Microsoft
kludged around that limitation by introducing its FAT32 extensions -- a 
cure arguably worse than the disease.  (It was even slower, more fragile, 
more fragmentation-prone, and more RAM-hungry.  But it _did_ make possible
constructing ludicrously large hard-drive partitions on a filesystem design
that was ideally suited for 160 kB floppies two decades earlier.)

There is a 2 GB per _file_ (filesize) limitation that is slowly being
eradicated from the various 32-bit Linux ports (such as x86).  See:
http://www.custhelp.com/cgi-bin/varesearch/solution?11=000523-0003&130=0959067317

> In a nutshell, are there FAQs walking a new user through adding a hard
> disk to an old machine?

The Large Disk HOWTO is a pretty decent place to start -- though it's more
about Linux than about hardware issues.  On the latter, since you insist on
using ATA, make sure you end up with _all_ drives on each ATA chain jumpered
correctly (not just the drive you're adding).  When there are two devices on
a chain, one must be jumpered as master, the other as slave.  A device
sitting by itself on a chain should be jumpered to either master or
"standalone" -- the latter being a third state that is sometimes present.
Check your drive's docs.

Also, if remotely possible, you should make sure that any ATA devices you 
want to be able to gain access to concurrently are on different chains:
ATA controllers don't do the "disconnected mode" operation required for
concurrent access to both devices of a chain.[2]  

> What should I get, EIDE, ATA, ATA adaptor or not?

SCSI.  ;->

Only since you asked.  But you'd rather be confused, have bizarre failures
and incompatibilities, and "save money", I'll warrant.

[1] It, in turn, is just a warmed-over variation of the old ST-506
interface for MFM, with almost all electronics leaving barely more than 
buffer circuitry moved to the hard drive (thus the term "Integrated
Drive Electronics").  The wire between that buffer and the hard drive
electronics is what was then laughingly dubbed the "ATA bus".

[2] Somebody recently claimed that Yet Another Bizarre ATA Extension
somewhere can now support concurrent access in mumbledy-mumble
circumstances.  I neither know nor care about details.

-- 
Cheers,      "Transported to a surreal landscape, a young girl kills the first 
Rick Moen     woman she meets, and then teams up with three complete strangers
rick at linuxmafia.com       to kill again."  -- Rick Polito's That TV Guy column,
              describing the movie _The Wizard of Oz_




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