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.