The ultimate system glue goes underground

If you wanted to link and access all computer-based systems and devices across a distributed site, also providing a universal, common MMI for operators and managers you’d need one hell of an open real time database environment to provide the `glue’!

That’s just what London Underground’s Major Projects Team is doing – and it’s selected Polyhedra’s object-based real time relational database and software tools for the pilot project. Polyhedra will provide the foundation and the prototyping facilities for what will be a universal MMI and information handling system – first for the new Northern Line project, but eventually for the whole of London underground.

Why Polyhedra? Dr Nigel Day, the company’s technical director, told Sys.Build: `Because it’s so much more than a database. It’s memory-resident, object-based and relational with a lot of extra features for multi-user, distributed client-server applications that are very highly real time.

`First, it’s got Active Queries; you get automatic hot updating from clients to server of all changing data – but without the overhead of polling. Limits are entirely configurable and it’s automatic and transparent.

`Second, the database is internally object-orientated with attachable program scripts for object methods. Our own, built-in fourth generation language gives the database designer all this. And, it means that Polyhedra becomes an active system component, communicating directly with other databases, systems and external rapid data devices.

`Third, Polyhedra is very fast. It can handle a few hundred thousand records and fits into memory – so there’s no disk swapping. But it’s also geared to vast amounts of fast-changing little bits of data from a lot of very diverse data sources – switches, ADCs, transmitters, PABXs, PLC databases – you name it.

`On top of all this it’s got good persistence, fault tolerance and warm restart features – plus connectivity with Oracle, etc and access via ODBC, DDE and so on. Just as important its pretty well platform-independent. It runs on Windows NT/95 and UNIX.’

This pilot system is likely to be on Windows NT using a dual Pentium system. But, it could equally use Dec Alpha, HP-UX, RS-6000, SparcStations, etc. Initial aim is to develop a London Underground Chief Engineer’s Standard for station systems and to test it in the open environment. Polyhedra is to interface an MMI to communications systems, like CCTV and PABX on a station.

But this will then be extended to include all operational systems, including signalling and control, trunked radio, public address, customer information and SCADA for power and station electrical and mechanical equipment – eventually linking all of the stations throughout the underground network.