A key moment in all the best war movies is the scene just before the combatants are due to embark on the raid when everybody synchronises watches. When you network a string of computers, each has its own little clock ticking away – but who goes around synchronising all those clocks so that they agree with each other? Precision Standard Time Inc, location unknown, reckons that clocks out of sync with each other can lead to major problems, and has come up with a solution – at least in the DEC VAX world. The company’s Time Source network software enables a DEC VAX equipped with a Time Source unit to operate as a network time server, synchronising DECnet nodes to a standard time signal. The software is available for VAXstation, MicroVAX and VAX processors using VMS 4.2 or higher. With Time Server software on the host computer, the Time Source unit communicates with any DECnet node using the new Time Client software. In addition to synchronising the processors, the tamper-proof time and data information distributed by the Time Source can be used by application programs for audit-worthy timestamps. The Time Source is a precision timing device that synchronises the calendar clock of a VAX to the international time standard, Co ordinated Universal Time. The company reckons that the product is a solution to the growing problems caused by unsynchronised clocks in networks, which can result in inadvertant data loss and errors in event co-ordination. The Time Source runs unattended and sets itself from signals that are broadcast continuously by the US National Bureau of Standards – and cannot be set in any other way. The new software products synchronise processors on an Ethernet to within 100mS of each other and can synchronise an entire DECnet wide-area network to within a few seconds. For applications requiring closer co-ordination, a Time Source can be installed on each local segment of a wide-area network to minimise transmission uncertainties for the timing signal. Network nodes can be synchronised to within 30mS of Universal Timme by attaching a Time Source unit to each node. Software licences vary by processor type: on a VAX 8500, Time Server software is $1,000 and Time Client is $400. For a MicroVAX, Time Server software is $250 and Time Client is $100.
