Sun's containerised Blackbox data centres can now have larger data centre servers and storage installed at the expense of losing one standard rack.
A Blackbox shipping container in its S20 format has a row of four standard 19-inch racks, 78.1cm deep and aligned sideways along each side of the container. In the new D20 format one side now has just three racks but deeper 115cm racks. It enables deeper Sun kit to fit in - kit you couldn't install in a Blackbox before.
This means enterprise-class SPARC servers such as the M4000 and M5000, the modular StorageTek 9985V disk drive array, and a StreamLine SL8500 tape library. You can't get the biggest Sun hard drive array - a 9990V - in because it is a multi-frame monster. Likewise, StreamLine expandability is limited.
The downside is that you lose 40 standard rack units, with the S20 having 280 of these and the new D20 having 240. But by losing 40 roundabouts you gain space for swings which you couldn't have in the Blackbox IT playground before. ®