Potential Issues when Upgrading Your Hard Drive

Q   I’m running out of space on my current hard drive and would like to either replace it
or add a second drive. I’m considering one of the
new 60GB drives because they’re so inexpensive, but
I understand they don’t necessarily work with
older computers.

Would I be wasting my money to buy one?

— B.J.

A    First of all, I’m assuming the drive you are talking about uses an ATA (also known as EIDE or IDE) interface, not a SCSI interface.
Most mass-produced consumer computers have ATA drives. The answer to this question depends
upon several factors related to your computer; namely,
the BIOS (Basic Input/Output System) it uses, the
operating system you run on it, and the file system
you use to format your drive.

To understand where the problems can occur, you need to understand how software talks to the
hard disk. When your application software wants to
transfer information to or from the hard drive, it calls
file management functions in the operating system
(Windows 98, Windows NT, etc).

The operating system communicates with your computer’s BIOS using the Int 13 API (Interrupt
13 Application Programming Interface). Finally,
your BIOS transfers information to and from your
disk drive through ATA interface calls.

To even consider installing a 60GB drive, your computer should be fairly modern to begin with.
If your computer is more than five years old, you
will probably have to replace too many software
and hardware components to make the upgrade worthwhile. If your computer is three years old or less,
you will probably not have too many difficulties.

The first thing you need to consider is your
BIOS. The original Int 13 API didn’t support drives
larger than 528MB. Later implementations increased
that limit to about 8.4GB, but for even larger drives,
your BIOS must support "extended" Int 13
functions. Check your computer manual or ask the
manufacturer about whether your BIOS supports
extended Int 13 functions. If it doesn’t, you can usually get
a replacement BIOS chip or a BIOS extender card
that overrides your current system BIOS. Some
drive manufacturers provide software you can install
that works around the limitations of an older BIOS.

The next potential trouble spot is your
operating system. DOS, Windows 3.1, the Windows 95
upgrade for DOS, and Windows NT (prior to version
4, service pack 4) do not support drives larger
than 8.4GB. Window 95, Window 98, Windows NT 4.0 (SP4+), and Windows 2000 do support drives
larger than 8.4GB. For installing NT on a large drive,
see the Microsoft Knowledge Base article Q197667.

Finally, the file system you use to format the
drive can affect how much you get out of it. The FAT
file system (FAT16) is limited to a 2GB-partition size,
so you would have to create 30 partitions, but you would run out of drive letters first! For Windows
95/98 systems, you’ll need to use FAT32. On
Windows NT, you can use FAT32 or NTFS file systems.

The bottom line here is that, the more modern your system, the more likely it is you’ll be able to
use one of the new high-capacity disk drives. If you
have an old system, you should consider upgrading
your computer or settle for a smaller drive.