Portable computers were all the rage on the opening day of the Which Computer? Show in Birmingham yesterday, and Sir Clive Sinclair showed that despite his tribulations, he has by no means lost the power to draw the crowds and to win plaudits from hard-bitten journalists. The new Z88 portable computer from his Cambridge Computers Ltd company – to be manufactured by Thorn EMI and initially sold mail-order – makes a better compromise than most between functionality and convenience. At 30 ounces and measuring 11 by 8.25 by 0.875, it is unquestionably portable, and comes with an 80 character by eight line supertwist blue-on-grey LCD display that also puts up three windows – file status, machine status and a dot representation of the full 64-line page so that people doing word processing can see where they are. It has just four internal chips – a Z80 CPU, a 256K-bit – 32K-byte – memory chip, and a ROM containing BBC Basic and the operating system; word processor, spreadsheet, diary and file system are also included, and additional software comes on ROM packs; there are three slots for these, which can also be used to expand main memory with 32Kb, 128Kb or, in due course, 1Mb plug-in units. The software, not all of which is ready yet, is being done by a company called Protechnic Ltd. The machine runs 20 hours on four penlight batteries. The keyboard is silicon rubber, and the machine also includes an RS232 port. It costs UKP200 plus VAT, and extras include a UKP15 cable to exchange files and data with IBM Personals, a UKP10 mains adaptor, and a UKP100 modem is planned. Deliveries are set for April, and Sir Clive is looking to build 70,000 in the first year at a rate of 10,000 a month.