Some time ago 250-gigabyte hard disk drives could be found but rarely in notebooks and external storage devices and were practically unavailable in retail shops, so we had problems writing our review of them. The situation has changed considerably since then. Notebooks with a hard disk of that capacity are widely available in shops, and you can easily buy an individual 250GB 2.5-incher in every computer shop. Therefore we have collected 2.5-inch hard disk drives from every manufacturer by now, adding models from Seagate and Toshiba to those of Fujitsu, Hitachi, Samsung and Western Digital we tested earlier.
The perpendicular recording technology has been progressing, too. It has increased the data density per platter to 160 gigabytes by now. This is not such a tremendous breakthrough as the previous transition from 80GB platters with longitudinal recording to 125GB platters with perpendicular recording when the storage capacity increased by a half, but quite a hefty addition nonetheless. This technology seems to have neared the maximum recording density available with it, and some manufacturers are already thinking about new ways to develop hard disk drives even further. That’s the future, though. So, let’s be practical and live in the present, especially as we’ve got two achievements of perpendicular recording in our hands: 320GB dual-platter hard disk drives from Western Digital and Toshiba.
As we know perfectly well, a higher recording density ensures a higher speed of reading from and writing to the platter because the read/write head can fly over more sectors in a higher-density drive in the same time. The correlation is not proportional, though. It is harder to seek for the desired track and keep the head above it when the recording density is higher: such operations take more time and reduce the resulting data-processing speed. The firmware algorithms are important, too. 8 megabytes of cache memory is the standard amount today and the drive’s performance depends greatly on how effectively it can use the cache for look-ahead reading and deferred writing. Well, this is only theory. Again, we are going to be practical and will just benchmark six 250GB and two 320GB drives to compare their real performance.
We’ll say a few words about each newcomer first.