The problem for companies like Siemens Data whose mainframes are derived from copies of IBM’s original 360 – the Siemens 7.500 series is the only surviving direct descendent of the RCA Spectra 70 copy of the 360 – is that they are locked into the ancient IBM architecture, and have to follow whatever IBM does – but several steps behind. Thus it is that only this week, Siemens Data has finally announced extended architecture 31-bit addressing on its 7.500 mainframes, with the first XS Extended System Architecture release of its BS2000 operating system, which doubles the maximum number of concurrent tasks to 512. But in at least one aspect of its product line, Siemens is well ahead of IBM – it has no incompatible sidetracks to worry about, and where IBM offers the System 36 and System 38, 8100 and 9370, Siemens has only the 7.500 line, running variants of BS2000 right down to System 36 level. Siemens has run out of 7.500 numbers and has brought in a new top-end machine called the H120, which comes in three models, the 35 MIPS F uniprocessor, the 60 MIPS I dyadic, and the 65 MIPS P dual processor, described as more than twice as powerful as the previous top-of-the-line 7.590-R, which is a Fujitsu M380 adapted and microcoded to run BS2000; it is not confirmed that the new H120s are based on the Fujitsu M-780, but it is likely. The 120-F comes with 64Mb to 128Mb of main memory, and uses an eight-channel input-output processor. It can be field-upgraded to a 120-I with up to 256Mb, and a 120-P, which is two complete Model Fs tightly coupled. And at the other end of the scale, Siemens has answered the IBM 9370s with the 7.500 C30 and C40, which it describes as office computers. The C30 comes in three models, B, D and E, supporting 10, 20 and 30 workstations and offering a three to one power range. They come with 4Mb to 32Mb of memory and two 250Mb disk drives as standard, with three 600Mb drives the maximum. The 7.500 C40 also comes in three models 7.500, C40-F, H and S, the S being a dual processor. They support 30, 60 and 100 workstations respectively and from 8Mb to 64Mb of memory, with up to 15Gb of disk. The new machines all have 31-bit addressing built in, as of course does the 7.590, being based on Fujitsu’s first generation XA machine, but the existing 7.560, 7.570 and 7.580 4381-class machines are confined to 24-bit addressing for a maximum of just 16Mb. No prices are available for the new Siemens machines, but they will be made available in the UK in due course.