Siemens Nixdorf Informationssysteme AG is developing a multiprocessing personal computer that’ll start life with up to four Intel Corp Pentium chips, running Microsoft Corp’s Windows NT operating system. Due in the second quarter of next year, the machine, originally code-named the A20, could eventually go up to 20 processors. Siemens Nixdorf says the box is aimed at the very high end of the personal computer market where low-end Unix RISC technology is currently positioned. Siemens Nixdorf will differentiate its lines by offering Windows NT on its personal computers and Sinix Unix on RM RISC workstations, according to Claus Hommer, director of business planning at Siemens Nixdorf’s personal computer Business Unit. Siemens was a reseller of Sequent Computer Systems Inc Balance multiprocessors, but as reported, Corollary Inc, Irvine, California, will provide its C-bus II multiprocessor bus architecture and Symmetric Integrated Multiprocessor Logic chip set for use in Siemens Nixdorf’s multiprocessor.