OPEN systems are now an established fact of life in the Hongkong computer market, but their companion, client-server computing, has been slower to find commercial acceptability. Since the Hongkong Government's adoption of Unix-based systems as its preferred mid-range platform, the industry-standard operating system has gone way ahead. It seems now that few new development projects based on proprietary computing technology take place outside the mainframe sphere. This broad acceptance of open systems, however, has not so far been matched by the adoption of the client-server computing. Part of the reason for this slow take up is that, unlike the move to Unix, the adoption of client-server represents a major shift in the way computing should be done. Johnathan Chiu, Hewlett-Packard Hongkong's project manager for application systems, believes there was still a lot of misunderstanding in Hongkong about client-server computing. He said benefits were that the systems accrue in three phases - user payoffs, better integration, and more efficient use of Information Technology (IT) resources. ''One of the contributing factors to the market perception that client-servers are just personal computer operations comes from the fact that the immediate benefits, such as better data access and productivity improvements, are focused on the user and the PC,'' said Mr Chiu. ''The enterprise-wide benefits really start to kick in when the infrastructure has been put in and the organisation is able to migrate significant applications off the host computer. Once companies have made their migration, the benefits continue because client-server architecture is inherently more flexible than traditional host-based system. This means applications are more easily updated to meet changing requirements, with IT manpower resources more usefully focused on solving business problems.