ParaScale, a Cupertino, Calif.-based storage software company that debuted in June 2008, today announced the availability of its ParaScale Cloud Storage (PCS) software, which allows companies to turn commodity Linux servers into an Amazon S3-styled storage cloud. Sony Pictures Imageworks and Stanford Genome Technology Center are two companies currently using PCS. A handful of hosting companies such Carpathia Hosting are using ParaScale software to offer their own public storage clouds.

ParaScale’s software release, while 6 months behind schedule, comes at a time when there is growing interest in private storage clouds at large companies. Big demand is yet to materialize, however. These private and low-cost storage clouds are likely to be used as a replacement for tape drives, which are used for backing up corporate data, much of which is never retrieved. Blue Coat Systems is using PCS for a cloud storage system for precisely that reason.

The company plans to charge for the software based on the size of the storage cloud. It will cost about $1.05 per gigabyte of storage. ParaScale competes with Amazon (s AMZN), NetApp (s NTAP), Islion, EMC (s EMC) and Sun Microsystems (s JAVA) in what is generically referred to as the scalable network-attached storage business.