... is one of the classical buzzwords (not only in object oriented programming). It can mean nothing or everything.
DM gives you safety against yourself (you, the programmer). You are responsible for the bugs. You must get everything working in an extremely short time. So, you are the biggest danger.
DM is tolerant against most errors. It always tries to get the best result from the current situation. It does its best not to crash an application. In short: it is robust.
... gives safety. Its a more pragmatic than safety - it is possible to design a robust system. Designing a safe system is more difficult (if it is even possible at all).
DM is robust. So it works very carefully. Before anything is done, DM checks all conditions which must be fulfilled to complete the task. If some condition is not met, a warning is issued (if you asked for such warnings) and the job is just not done.
But the application will not crash.
A typical situation is the use of an non-existent object. This would normally result in a system crash. Not with DM. It makes the usage of these objects impossible (for example by disabling any button calling a feature of a non-existent object).
The most important benefit of object oriented programming is the enhanced maintainability. It is possible to change one part without interfering with the rest. This reduces the testing efforts necessary and it increases the safety.
DM follows the same strategy.Pictures (or forms) are independent of the basic algorithms of the virtual machine. They are based on it, but they are represented in a totally different way. We have two independent parts - the virtual machine and the graphical application. Both can call the other - but the coupling is not very tight and if for same reason the interface does not work, the application will not crash. And, you can change either of them without interfering with the other.
Although forms are always independent of the virtual machine, the virtual machine must be changed when functionality is requested which was not available before. It is not possible to write program functionality into the form itself (or at least only in a very limited way - a sequence of procedure calls). This has...
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