Original URL: http://www.theregister.co.uk/2010/07/30/xiotech_katana/
Xiotech forging secret Katana project
HDD & SSD hybrid craftsmanship?
Word has reached us of a development project codenamed Katana inside Xiotech, with hints that the project involves HDD and SSD hybrid craftsmanship.
Xiotech's ISE  (Intelligent Storage Element) data pack bundles a set of hard disk drives inside a sealed 3U canister and turns them into a single super-drive. It has RAID inside the canister, faster performance than from the same number of drives inside an ordinary enclosure, and a five-year warranty against ISE failure. There is a huge amount of disk drive diagnostic and management IP to enable ISE disk drives to fail in place and still be partially used, which is essential to enabling the warranty period.
Katana is an ISE development project. A Katana sword is a curved blade made from two metals: a high-carbon steel and a low-carbon steel. The high-carbon steel holds a sharper edge than the low-carbon steel but is brittle and may break when struck fiercely. The low-carbon steel is less brittle but loses its sharpness. In a Katana sword a length of the low-carbon metal is placed between the sides of a U-shaped channel made of the high-carbon metal.
The combination is then heated and hammered flat and folded over itself, and these steps are repeated up to sixteen times. The metal is then hammered into a basic sword shape and given a curvature by being heated and quenched while coated with clay-based slurry that is thicker on the sides and spine of the sword than the edge. The end result is a sword that holds its sharpness pretty much as well as a pure high-carbon steel blade but absorbs blows like a low-carbon blade - the best of both worlds.
Using this as a metaphor for ISE we can see that the product currently uses hard disk drives (HDD) inside its case. It does not use solid state drives (SSD). We could imagine that Katana involves having an ISE with both HDD and SSD elements inside it. The SSD could be used to hold the hottest and most active data, with the rest of the data stored on HDD. Some ISE software would move data between the two tiers, and the SSD could be treated as a cache, holding a copy of the hottest data on the HDDs. Alternatively it could be used as a straight tier of storage holding unique data, which is written to the HDDs as it ages and is no longer hot.
We might hear more about this as the third quarter transitions into the fourth quarter of the year, or perhaps in the fourth quarter itself. ®