This column will discuss the latest in hard drive technology. Before we start, my faithful readers will probably remember that the term "hard drive" refers to the component in your computer that stores your data files. It does not refer to the entire computer box (or "system unit"), which also contains your RAM memory, processor, video and sound cards, CD drive, etc. I have no idea why it is common local parlance to call the entire box the hard drive, but who knows how these things get started!
Hard drive sizes are steadily increasing. Most PC systems now ship with 80 GB (gigabyte) hard drives, and finding PCs with 200 GB or more are now common. This is, of course, vast overkill for the average user unless you are getting into video film clips or storing lots of MP3 music files or digital camera pictures. But, even so, you need a LOT of MP3 clips or images to fill even a 40 GB hard drive. Video remains as the application that chews up the gigabytes.
The speed of hard drives has increased a bit. Some hard drives now have larger internal buffer storage, and some support the newer ATA133 interface. But ATA133 does not run any faster than the older ATA100 interface, because either interface is faster than the physical hard drive itself, even using the newer 7200 RPM rotational speed.
The bottom line here is that to day you should buy for price (you probably don't need those huge amounts of storage) and either ATA100 or ATA133 is OK.
So, having said that, what is really new? There are two things, one of these actually fairly old.
Towards the end of this year, you will begin to see hard drives using a new interface, called Serial ATA. The term "serial" refers to sending all the data on a single wire, as opposed to "parallel" which means that the data is sent simultaneously in groups of 8, 16, 32, or 64 wires. Now, you would think that parallel is faster, because you are sending the data with multiple wires instead of one. But as technology has matured, this is no longer true. The physical constrains of parallel cables and interference between the signal wires (called "crosstalk") limit the speed of a parallel interface. Serial ATA will be easier to connect and the cables will not be the wide, flat cables of today's ATA100 interface. This will improve internal airflow in the PC, along with improving the potential speed of the hard drive interface drastically.
The second improvement is called RAID (Redundant Array of Independent Devices). RAID is a way of connecting more than one physical hard drive to improve either the performance or the reliability of the data. Raid goes back to the early 80's, where it was used first in mainframe computers. But newer technology has now decreased the cost of RAID to where it becomes practical for PC users.
RAID allows you to simultaneously use more than one hard drive. The question is: how are they connected? Well, it turns out that there are a number of different ways, each bearing a certain RAID number. RAID 1 implements mirroring. Mirroring basically uses a special PCI card in your PC that connects to two hard drives, but it appears to the PC software as one hard drive. Data is automatically copied by the RAID card to the second drive, thus creating a dynamic mirror image of the first drive. Thus, if the first drive fails, you can just switch to the second one. RAID 1 gives your system a higher level of reliability, but it does not increase the speed of the hard drive system, nor increase its size.
RAID 0 implements what is called striping. Your data is divided between the two (or more) hard drives. This delivers a performance improvement, because you can read and write the data to the two hard drives simultaneously. RAID 1 also effectively doubles the amount of hard drive data capacity, because both hard drives hold unique data. But RAID 0 does not provide any level of reliability over a regular hard drive system.
There are lots of other RAID modes, which provide increased speed, capacity, and reliability. These modes cost more to implement because they require more than two hard drives, and more expensive hardware to run them.
What you will see in the future is more RAID 1 drives for reliability and RAID 0 drives for performance. If you want to add RAID to your current system, the hardware prices are (to me!) reasonable.
(Bob Seidel is a local computer consultant in the Southport / Oak Island area. You can visit his website at www.bobseidel.com or e-mail him at bsc@bobseidel.com).