3rd Platters and the 228 Year Old Hard Drive


For most 2.5” inch drives (or simply laptop hard drives), 1 or 2 platters (platters are the actual disks where the data is stored) have been the de facto standard for a number of years now.

But, around this time last year, Seagate brought out their Savvio drive with 3 platters in it.  Now Western Digital have thrown their hat into the ring and brought out their own three platter 2.5” drive called the S25. This disk, like the Savvio, has a capacity of 900GB. On their website, Western digital claim the drive has a whopping 2 million hour MTBF (mean time before failure). Now, over the years I have heard some ludicrous claims proffered by drive manufacturers but claiming this MTBF figure (i.e. half the drives will fail within 228 years of operation) is farcical.

One of the largest hard drive studies ever untaken in the world “Failure Trends in Large Disk Drive Population” was conducted by the engineers at Google. It helps shed some light on some of the manufacturer’s claims. They noted “situations where a drive tester consistently ‘green lights’ a unit that invariably fails in the field” In other words, in manufacturer’s tests, they pass drives that would fail in real life.

Storage could be considered a critical area of the I.T. industry. Everyday we rely on hard drives from surfing a webpage, to storing a thesis and to companies storing whole databases on them.  Computer users (consumer and enterprise) want storage options that have reasonable performance coupled with a reasonable level of giga/tera-bytes at a reasonable price. They do not want spurious numbers or claims pulled out of the air so some marketing department can get their egos stroked. With realistic expectations of hard drive failure rates, users can formulate better disaster recovery plans. Forewarned is forearmed.