Proprietary is not always the answer; open source is not always the answer.

Unix

Our principal focus has been on relational  databases running on one or another flavor of UNIX: AT&T System V, BSD, Solaris, and so on. These platforms are generally stable; they usually have better MTBF's than NT does. And they offer a rich tool set in support of the basic relational database functionality.

In the early stages of a project it is usually necessary to tune the operating system and database – i.e. experiment with operating system and database options, buffer sizes, disk and table layout and so on – if best performance is to be seen. Typically changes have to be made to database and operating system in parallel.

Frequently a second wave of performance tuning is required on elevation of the project to production. In principle, this could be avoided or minimized by preventive load testing. In practice, it can be difficult to see where the loads are coming from until the system is up.

NT

The relational database offerings on NT platforms are dominated -- logically enough -- by Microsoft's SQL Server and Access products. The aggressive use made by SQL Server of the underlying NT features can offer significant benefits in ease-of-use. Of course, this tighter coupling can create corresponding vulnerabilities as well: it is sometimes necessary to reboot an NT box to clear a problem with SQL Server -- if the database and operating system were in fact completely decoupled, this should never be necessary.

DOS

Even in Windows 2000, it still seems sometimes necessary to get down to the DOS level. And DOS is sometime unavoidable when dealing with legacy hardware and software systems.

has written operational systems and hardware control code (in C and assembler) for DOS systems. And has provided design and debugging consultations for DOS databases.

Macintosh

With OS X, Apple appears to have been successful in making the Mac into what is essentially a UNIX box. In fact, much Linux code ports to the Mac with little or no effort, and a small cottage industry has sprung up to do this. Given that the Mac is in some ways still the friendliest GUI, this may lead to a revival of this platform.

Other operating systems

In several cases has worked with virtual operating systems, e.g. IBM's MVS configured to look like UNIX, NT Windows made to look like an Amiga.

These offer some interesting capabilities for dealing with unusual problems, but the almost inevitable performance hits make these usually something of a last resort.