Insurance companies and hospitals depend on large mainframe computers, many of which run customized software. Service bureaus and medical groups generally rely on work stations, which are more powerful than personal computers but smaller than mainframes. Physicians use PCs or workstations for record-keeping and billing, relying on commercially available software or on customized programs provided by hospitals or managed care organizations. The software running on mainframe computers consists of hundreds of thousands of separate instructions, many of which may refer directly or indirectly to dates. As problems are identified and fixed, the revised lines of code must be tested to ensure that they cause no unforeseen problems.
Work stations use powerful, high-speed chips with many instructions permanently built in.
Generally, computers and software sold since 1996 are assumed to be Y2K compliant, but that isn't always true. My concern is that not all physicians are getting an upgrade. Some of them are working with dated software that hasn't had an upgrade in years. Simply making sure that systems are currently compliant is not enough to prevent a millennium disaster. Information that has been stored under older versions of programs that have been upgraded may suddenly become inaccessible in the year 2000, so testing must be broadened to make sure that nothing is lost when the century changes.