Toshiba Corp is starting sample shipments of 4M-bit memory chips this month, beating Hitachi Ltd to the punch and claiming the first Japanese firm to offer 4M samples – Siemens AG says it has been sampling them since June, but Toshiba says that it too has been handing out samples to computer manufacturers sinnce the summer: it is upgrading the 1M lines at its Oita plant at a cost of $80m for the new parts, and plans volume production of the part, with an 80nS access time, from next spring at a rate of around 100,000 per month; Hitachi has been promising has said that it will start shipping 4Ms by the end of 1988.