If there is a rash of very high-performance Unix supermicros coming out over the next few weeks, the explanation is that the US Air Force has now put out formal invitations to tender for up to 20,000 Unix systems, the requirements are exacting, but the business is irresistible and bids have to be in by May 20. NCR’s contender, the new Tower 32/800, is already out, and Computer Systems News reports that AT&T Information Systems will bring out its offering in the shape of the 3B2/600 on March 24. The paper hears that the 600 will initially come with one or two 18MHz 32100 microprocessors – the 3B2/400 uses a 10MHz version, and will take 4Mb to 16Mb main memory, have a 6Kb cache, 250Mb to 3Gb of disk, and Unix System V.3.1. It will have 26 to 90 ports, and will feature AT&T’s first SCSI bus for disk support. Performance is rated at 2.4 to 4.7 MIPS, and the configuration compares with a maximum 4Mb main memory and 720Mb disk on the 3B2/400. Most noteworthy feature of the new machine is that it has been designed to be upgraded easily to the new WE32200 microprocessor running at 30MHz as soon as that chip is available in sufficient quantities; general availability of the 32100 version of the 3B2/600 is set for June in the US. Word is that IBM is also working on a contender for the Air Force contract, but there are no indications as yet whether it will be a 9370 with Unix or an RT – or something else again.