Hard Drive Buying Guide

Hard drive buying tips

First, be sure your new hard drive will interface (connect) with your computer. Several interface technologies are in use: SATA and PATA (or IDE) are the most common in small business and home computers; SCSI is popular on servers and FC is almost exclusively found on servers. Unless you're a computer designer, you probably don't care what the acronyms stand for, you just need to check the hard drive description and your computer's hard drive and make sure the interfaces match.

Second, decide what size computer hard drive you need:

• 40GB or 80GB internal hard drives are the common factory-installed hard drives and, for the casual user, have plenty of memory.
• Mid-size hard drives, 120GB to 250GB, are also common and very affordable; these are great choices for users who want to digitize their whole life, including certificates, documents, the family photo album and a few home movies.
• Big hard drives, 300GB to 1TB, are the premium models, and you will put out serious money for them.

If you have high-memory applications such as DVD home movies, or you run a business with inventory, accounting and a host of other programs, bigger is better and worth the extra money. Even if you don't think you'll need the space, super-sizing your new hard drive is a great plan. Depending on the model, a 250GB drive and a 500GB drive might be close to the same price, and you will probably fill up either sooner or later. If you have an older machine with a slow CPU and limited RAM, you may need to upgrade those to get the most out of your new hard drive. Even with those additional components, upgrading is often less expensive than buying a new computer.

Third, decide how much speed or security you need. "Redundant Arrays of Independent Disks" (RAID for short) can write data to several hard disks at a time. RAID-0 makes your computer system run faster by writing the data to more than one drive; hard drives can then be searched simultaneously. The one downside is serious: lose one drive, and you lose them all. RAID-1 writes the same data to more than one hard drive, creating instant backups of data. Should one drive crash, the other can continue to operate. The only downside is the need to match sizes: if you have a 120GB drive with an 80GB drive, you can't store more than 80GB on a RAID-1 equipped system. Check to be sure your motherboard or drive controller support RAID; for this, you might need a trip to the computer shop.

Hard drive categories

Internal

An internal hard drive is one designed to be installed in a computer. Hard drives don't fail often, so most people replace their internal hard drive because they need more memory. If you go this route, replacing the factory drive isn't absolutely necessary. Many CPUs have space for two or three internal drives, known as "master" and "slaves." If you want a 120GB hard drive, but the factory only installed a 40GB drive, you can add an 80GB drive to your computer. You get the 120GB you need, but you only pay for 80GB.

External

An external hard drive is a stand-alone unit attached to your computer system via USB or FireWire cable. An external hard drive is the easiest, most secure way to create back-up copies of all your files. Some include automated download software that allows you to backup your internal hard drive with the flick of a switch.

For those who deal with numerous, large (multi-GB) files that need to be shared among several computers or locations, an external hard drive is a necessity. It's the quickest, simplest way to move files too large for flash drives or email. Another advantage is "cross-platform compatibility." That's tech-speak meaning external hard drives work with PCs and MACs.

Hard drive terminology

Computer Memory:

• Bit: A contraction of "binary digit," it's an information datum, a single 1 or 0.
• Byte: 8 bits, one unit of information storage.
• Kilobyte: Approximately 1,000 bytes; a "typical" page with single-spaced text (no pictures or graphics) contains 500-600 words and could require anywhere from 5KB to 50KB, depending on the file formatting used by your word processor.
• Megabyte: Approximately 1 million bytes; a 3-inch by 5-inch color picture at 150 dots per inch (dpi) runs about 1MB. A typical CD holds 750MB, good for 80 minutes of audio.
• Gigabyte: Approximately 1 billion bytes; few hard drives are not measured in gigabytes. A 1GB MP3 player holds about 8 hours of audio. The latest edition of a world-famous encyclopedia occupies 1.2GB. A typical DVD is 4.57GB, good for just over two hours of video.
• Terabyte: Approximately 1 trillion bytes or 1 million MB; the newest consumer electronics hard drives have just broken the 1TB barrier. This could be enough for your whole audio-video library and your personal history, even if you shoot a lot of home movies and live to be 100.

Cache: All computers, including external hard drives, have RAM and ROM. RAM is the active memory, and ROM is the archive. RAM is emptied whenever a drive is turned off; whenever you hit [SAVE], what you're doing in RAM gets copied to ROM and will still be there when you next start up the drive. More RAM makes it easier to work with larger files.

Spindle Speed: A hard drive's rotational speed is a good measure of the drive's performance, the higher numbers usually being the better performers. Some are as slow as 3,600 RPM; the most common spindle speed is 7,200 RPM, which is fast enough for most applications; the premium (expensive) models are 10,000 RPM.

Hard drive care

Modern consumer electronics require very little care:

• Never plug electronics into the power grid -- use surge protectors.
• Dust them off and spray the openings with canned air. Don't set your CPU on the dusty floor, especially carpeted floors.
• Keep them cool -- never put your CPU in an enclosed cabinet. If you live in a hot area, consider an extra fan for your computer system.
• If the disk makes noise, check the mounting -- hard disks should be installed flat, horizontal or vertical doesn't matter, but flat is important. If it's mounted incorrectly, get it fixed. If it's mounted correctly, you may be hearing the "click of death," meaning a crash is imminent, so see your computer repair professional immediately.
• Install archive/file recovery software on all your drives.

With just a little common sense, your hard drive will run like clockwork until it's a technological dinosaur.