Three Hard Drive Generations: What Has Changed?

The introduction of perpendicular magnetic recording (PMR), was an important step in increasing hard drive capacities above 1000 GB. The first terabyte drive, Hitachi’s Deskstar 7K1000, was based on a massive five platters, as it had not used PMR. The Seagate Barracuda 7200.11 was based on four platters despite using PMR. Samsung’s Spinpoint F1 at 1 TB capacity came a bit later, and was the first performance terabyte hard drive to deliver its massive capacity on only three platters, making it more efficient and faster as well. It also delivered a business advantage to Samsung, because the so-called sweet spot—which typically means how much data can be held on a single platter hard drive—could be moved to 250 GB to 320 GB thanks to the much increased data density. Still today, low-cost sweet spot storage is the key to volume hard drive sales.

Speed Up, Speed Down

A result of increased data density is improved throughput, as the heads can read or write more data for given physical parameters, such as spindle speed and drive form factor. Consequently, hard drives have managed to increase peak throughput from approximately 80 MB/s in 2007 to more than 120 MB/s in 2009.

These would be the figures in apples to apples comparisons of 7,200 RPM drives. However, since efficiency is at least as important as high performance, rotation speeds of mainstream hard drives are decreasing: Seagate’s Barracuda LP runs at 5,900 RPM, and the WD Caviar Green and Samsung EcoGreen products at 5,400 RPM. All of them deliver high capacity storage with much increased performance. As you will see in our comparison of Samsung’s hard drive evolution, the performance penalty due to the spindle speed reduction from 7,200 to 5,400 RPM is very acceptable: 3.5” power efficient hard drives still reach 110 MB/s today (as on the Samsung Spinpoint F2 EcoGreen).

Trend: Mobile Storage, Performance Storage, Capacity Storage

The market clearly is going into different directions. Netbooks require cheap, reliable, affordable and quick hard drives: these typically are 2.5” hard drives with one platter and a 160 GB capacity. Notebooks should offer more storage, hence 5,400 RPM 2.5” notebook hard drives with up to 250 GB on a single platter represent the mainstream. Prosumer devices are based on twin-platter drives of up to 500 GB total capacity. High-end notebooks run on flash SSDs or on 7,200 RPM notebook drives.

Desktop systems will increasingly be equipped with two types of storage: your system should be running on a performance storage solution. This could be a fast flash SSD or a RAID configuration of two or more hard drives. Individual performance drives, such as modern 7,200 RPM drives, will deliver sufficient performance for anyone in the mainstream or enthusiast segments. While system storage should deliver maximum performance, it does not have to provide lots of capacity. This can be taken care of by capacity storage hard drives, which are in many cases being relocated outside of the PC enclosure.

Take Out the Drive

Only a few years ago, increasing your storage capacity would have meant purchasing an additional hard drive and installing it into your PC. Today’s approach is more convenient: retail external storage kits are available from all important storage companies, and they offer up to 2 TB of storage in stylish enclosures, connected via USB 2.0, or preferably via fast eSATA links. Anyone who remotely cares about PC internals clearly should focus on a quick system storage solution plus additional storage, which will mostly be based on external 3.5” hard drives.