Serial Storage Architecture
(SSA) IBM's proposed ANSI standard for a standard high-speed interface to disk clusters and arrays. SSA allows full-duplex packet multiplexed serial data transfers at rates of 20Mb/sec in each direction.According to John Taylor, programme manager at IBM's Storage Division at Havant, SSA will be used in arrays of discs working with high-end computers ranging from mainframes down to LAN servers. Taylor said that SSA differs from the IEEE proposed P1394 serial interface specification in its ability to offer simultaneous multiplexed transfers from more than one disk or array. IBM also supports the P1394 standard which will be used primarily by desktop PCs for multimedia applications. SSA has received backing from a number of companies including connector makers Molex, ITT Cannon and AMP, disk drive makers Conner and Western Digital and RAID array suppliers like Dynatech and NCR. IBM expects to see the first SSA products released at Comdex in Autumn 1994 but it will be 1995 before the products ship in volume. Under an agreement signed with ASIC maker and ARM licencee VLSI Technology, IBM will use ARM-based chips made by VLSI to implement the SSA interface and VLSI will make these cores available to third parties as one of its Functional System Blocks.