In a move that is being described as a return to the mainframe market – the company originated the top-end Acos machines now the exclusive province of NEC Corp – Toshiba Corp has unveiled a new proprietary family called the TP 90 series, describing the machine as designed to replace general purpose computers at the heart of major networks. TP stands for Total Processing, an architecture designed to distribute tasks among computers and workstations on each level of the system network. It runs what Toshiba calls OS VII, an original operating system for the machine that implements what the company calls Network Virtual Computing. The operating system distributes tasks, such as man-machine interface, presentation graphics and transaction processing to optimised dedicated processors. The central processing unit consists of three large-scale applications-specific integrated circuits and the top-end TS90/77 model uses Toshiba’s new 4M-bit dynamic memory chips. The machine is claimed to offer three times the perfromance of Toshiba’s V7070 distributed processor. The external bus, which is expected to be available in spring 1991, will allow up to four machines to be linked. It also includes fault-tolerant features, including mirrored disks. No indication of prices was available.