However, there’s still some life in HDDs. They are unmatched when it comes to storing vast amounts of data at a relatively low cost. The addition of NAND cache can also boost performance to the next level, albeit not on par with true SSDs. Seagate is at the forefront of both trends – it already builds hybrid drives and now it claims to have the lead in high-capacity drives as well.
The world’s first 5TB drive, courtesy of Seagate, is expected to show up next year. Current hard drives rely on 1TB platters, hence the 4TB limit. The capacity of individual platters is limited by the width of magnetic tracks, which are now around 75nm wide and can’t get much smaller without compromising data integrity.
This is where Shingled Magnetic Recording (SMR) comes into play.
The new technology allows hard drive makers to reduce the gap between each track, effectively saving up to 25 percent of platter space which would be wasted using current technology. However, it is not as straightforward as that. Since SMR doesn’t have the track gap, when it writes data it also affects adjacent tracks, destroying the data. Therefore the tracks are further broken down into bands and the drives basically have to rewrite the affected data.
Although it might sound scary, Seagate insists it has already shipped a million SMR drives and that the impact on performance is minimal. Thanks to SMR, the capacity of individual platters will be increased to 1.25TB, making four-platter 5TB drives possible.
The real question is whether there will be a lot of demand for them.