Hard Drive

Hard Drive

Description
What To Look For
Recommendations

Already know what a Hard Drive is and what to look for? Then skip to the Recommendations.

Description:

• As the primary communication device to the rest of the computer, the hard drive is very important. The hard drive stores most of a computer's information including the operating system and all of your programs. Having a fast CPU is not of much use if you have a slow hard drive. The reason for this is because the CPU will just spend time waiting for information from the hard drive. During this time, the CPU is just twiddling it's thumbs...
• The hard drive stores all the data on your computer - your text documents, pictures, programs, etc. If something goes wrong with your hard drive, it is possible that all your data could be lost forever. Today's hard drives have become much more reliable, but hard drives are still one of the components most likely to fail because they are one of the few components with moving parts. The hard drive has round discs that store information as 1s and 0s very densely packed around the disc.

What To Look For:

• First, look at the technology. Do you want IDE or SCSI (see Glossary for definitions)? SCSI is the faster interface which also takes a load off of your CPU and allows for better multitasking. It also requires the use of a SCSI Card. SCSI is rarely used in home desktop systems, but for the user that wants the best possible performance, SCSI is the way to go. IDE is the more common hard drive interface, and it's what I recommend to most users. It is also a lot less expensive. Over the years, IDE has gotten a lot closer to SCSI in terms of speed too. But, if you are one of those users that wants the fastest possible computer, SCSI is one of the reasons you may want to Build Your Own Computer. If you can afford to go SCSI, you may want to consider a SCSI CD-ROM drive and burner.
  Other reasons to go SCSI are if you want a lot of devices (you can easily have 15 devices, IDE used to only allow for 4, but newer motherboards come with extra connectors, but still only allow for 2 devices per cable) or you really need the high speed 10,000 - 15,000 RPM drives.
• Have you decided on IDE? Okay, now do you want traditional IDE (parallel ATA) or the newer Serial ATA? Serial ATA is only possible with newer motherboards that support this connection type. It allows for easier drive connection, theoretically higher speeds, and has much thinner cables. Also the first 10k rpm ATA drives are available only as Serial ATA. Another thing to consider is FireWire (IEEE-1394) hard drives. These are mostly external though. It's a good option for transporting very large amounts of data back and forth between multiple computers.
• The most important numbers to look at in terms of speed are the rpms of the hard drive (revolutions per minute). The faster rpms are going to be much faster hard drives because they spin the discs faster providing faster access to a particular area of the disc. The most common rpm speeds for IDE drives are 5400 rpm, 7200 rpm, and now some at 10,000 rpm. I highly recommend 7200 rpm drives over 5400 rpm drives as they provide a big difference in speed. If you can afford it, get the Serial ATA drives that run at 10,000 rpm. For SCSI, the rpms are usually at 7200 or 10,000, with some newer drives as high as 15,000 rpm. If you're going SCSI, you've got money to burn, so you might as well get a 15,000 rpm drive.
• You should also pay attention to the access times. Lower numbers are better here. This is how fast the hard drive can access a particular area of the disc.
• Next, if you decide to use IDE, look for the Ultra DMA or Ultra ATA rating (both of which mean the same thing and mean that the bus is capable of transferring data at up to a specific rate). What this means is that if you have say 4 IDE hard drives and you only have ATA 33, then the drives would only be able to transfer 33 MB/second altogether. ATA/33 is really all that's necessary because most users only have one or two drives, and the chances of those drives ever being able to transfer more than 33 MB per second is very slim anyway. Having said that, there are currently ATA/100 and ATA/133 standards. Most newer hard drives are ATA/100 or 133, and I would suggest buying an ATA/100 drive at least, not because the drive would ever be capable of transferring data that fast but because it is a "newer" drive and thus is more likely faster than the ATA/66 drives, in general.
• If you decide to use SCSI, you need to consider the type of SCSI (yes, it gets more complicated). These are hard to define since different companies represent them differently. They consist of a mix of SCSI-1, SCSI-2, and SCSI-3 as well as Narrow-SCSI, Ultra-SCSI, Ultra2-SCSI, Wide-SCSI, Ultra-Wide-SCSI, Ultra160-SCSI, and now Ultra320-SCSI. The simplest way to decide is to look at the number of pins your controller has. If it has a 68-pin connector, then it has Wide capability. Find a hard drive that has a 68-pin connector and then look for the highest SCSI rating and/or the highest in the list above, with "Ultra320-SCSI" being the highest. Most CD-ROM drives and burners will be "Narrow-SCSI (50 pins), and most current SCSI hard drives are Ultra2Wide, Ultra160, or Ultra320.
• Next, look at the amount of cache on the drive. Many have only 128kb, 256kb, or 512kb of cache memory. Some SCSI drives have 16 MB of cache or more. I would advise trying to find an IDE drive with at least 2 MB of cache (most now do), and 8 MB cache is getting to be common (and makes a big speed difference). SCSI drives should generally have at least 2 or 4 MB of cache.
• The previous tips have all focused on speed. Of course, you also want to get a hard drive that will hold enough data. For this, you need to consider the GB size of the drive. Most of today's hard drives start at 40 GBs or larger. 40 GBs is going to be more than plenty for the vast majority of computer users. Power users may want anywhere from 120 to 250 GBs of space depending on their needs (i.e. if you want to store hundreds of CDs in MP3 format, you will want a very large hard drive). Consider 40 GB as a bare minimum size. You won't find many new hard drives smaller than that anyway.
• Warranty is also important since hard drives are prone to failure. Most IDE hard drives have a 1-3 year warranty, and most SCSI drives have a 5 year warranty.
• Also consider that the higher rpm drives usually run hotter than the slower ones. You may want to consider hard drive cooling fans for some of these faster drives.

Recommendations:

• IDE Hard Drives
• SCSI Hard Drives

IDE Hard Drives:
There are quite a few good hard drive options depending on your budget. IDE hard drives are usually fairly comparable in price for the same size, same rpm, so I generally suggest just going for the best performing drive with a good reliability record. Since the 7200 rpm drives aren't much more expensive than their slower 5400 rpm brothers, I suggest getting at least a 7200 rpm drive. I also suggest going for an 8 MB cache hard drive. They also aren't much more expensive anymore, and if you can be satisfied with a smaller amount of disk space (i.e. 80 GB), you can get an 8 MB cache drive for pretty cheap. Here are my specific recommendations:

• #1: Western Digital Raptor series (model WD740GD or WD360GD) - These drives are currently the fastest drives available unless you look at SCSI drives (and it even rivals some of the fastest SCSI drives). Unfortunately, they're fairly expensive and small. The largest one only holds 74 GB, and the smaller one only 36 GB. Nevertheless, this is sufficient for the typical home user. If you play a lot of games or have large MP3 or video collections, you'll need a different drive or a secondary drive for the large amount of data. These drives are Serial ATA only, spin at a fast 10,000 rpm, and have the large 8 MB cache buffer.
• #2: Hitachi (formerly IBM) Deskstar HDS7225*: The * represents the rest of the model number, which usually determines the size and whether it's parallel or serial ATA. Either one makes a good choice, but if you have serial ATA available on your motherboard, you might as well take advantage of it. Aside from the 10,000 rpm Raptors, these 7200 rpm drives are the fastest IDE drives available, plus they're quiet and inexpensive. They are available with a 2 or 8 MB cache, but make sure you get the 8 MB cache version (which also has a 3 year warranty instead of a 1 year warranty on the 2 MB version). The 160 GB version is a good choice since it's still relatively inexpensive.
• #3: Western Digital JB series drives - They range from 40 GB to 200 GB (and from less than $70 to about $400). Get whichever one fits your budget. I suggest the 120 GB version - model # WD1200JB. These all spin at 7200 rpms. The larger drives tend to be a little faster than the smaller ones. The only negative is that it's an ATA-100 drive (the Maxtor drives are ATA-133), but that's not a big deal at all. If you want a Serial ATA drive, the WD2500JD is as good as it gets (also with 8 MB cache). The Western Digital drives are actually faster and in many cases cheaper than the Maxtors and IBMs.
• #4: Maxtor 8MB cache drives: These are a little slower than the Western Digital and IBM drives, but a good choice if that's all that's available. Model numbers are written like this: 6Y120P0 or 6Y120M0 where 120 is the size in gigabytes and PO means IDE and MO means Serial ATA.
• #5: Western Digital Caviar BB series - These are about the same as the ones listed above, but without the 8 MB cache memory (instead it has 2 MB). Good choice for those on a budget.

SCSI Hard Drives:
SCSI hard drives are going to cost you a lot more, but the performance difference can be significant. IDE has really caught up in speed lately though, so it may be a better choice nowadays. Here are my recommendations for SCSI drives. All of the drives below are Ultra320 rated:

• Fujitsu MAS3735: This is currently the fastest hard drive available for server use, period. It's a 15,000 rpm drive with a seek time of only 3.6 ms and 8 MB cache.
• Maxtor's Atlas 15k is another great choice for a 15,000 rpm drive. It's a little slower in server applications, but for general desktop use, it is about as good as the Fujitsu. It has seek times of around 3.4 ms for the 73 GB version and 3.2 ms for the smaller drives.
• Maxtor Atlas 10k IV - This drive is a great option because it is the fastest 10,000 rpm drive and it is also reasonably priced (relatively). It has a very large 8 MB cache buffer and seek time of only 4.4 ms.