Shepton Mallet, Somerset-based Perihelion Software Ltd, developer of the Helios parallel processing operating system, has acquired for an undisclosed sum one half of Cambridge-based TopExpress Computer Group Ltd. TopExpress operates in two diverse areas – computer security, and wave mechanics and acoustics. It is the computer security end of Topexpress that has been acquired by Perihelion. TopExpress is owned by Vickers Ship Building & Engineering Ltd – the only part of Vickers that wasn’t floated. Dr Gray Girling, formerly with TopExpress and now with Perihelion, explained that Vickers Shipping has no interest in computer security, now that the defence business is contracting and it has been forced to focus only on its core activities – as a result of this decision, Vickers Shipping has withdrawn its support for the computer security end of TopExpress and, when a six-year contract with the Communications & Electronics Security Group Ltd in Cheltenham came to an end recently, TopExpress Computer Security could no longer afford to go it alone. In acquiring the business, Perihelion gains five highly skilled staff in the areas of fault-tolerance, network protocols and standards, quality assurance and software engineering, as well as access to offices in Cambridge.