Sony Corp’s erasable magneto-optical disk drives are now available in the US: the company is offering the SMO-S501 self contained subsystem and the SMO-D501 integratable model. It also offers two 5.25 cartridges for the drives, the EDM-1DA1 with 512 byte sectors and the EDM-1DA0 with 1Kb sectors, storing a formatted 650Mb and compatible with 3M Co’s erasable optical cartridges. Sustained data transfer rate is 7.4M-bits per second, and short-stroke seek time is 20mS, with access to up to 3Mb of data in less than 40mS; the average access time is 90mS. Single unit pricing for the drive will be $4,650. Sony already has a fan of the drives in Hewlett-Packard Co, which says it has been conducting extensive product performance and reliability tests of the products and is excited about the potential opportunities for mass storage.