The actual experience is that, where it matters at all, you have to think about it a great deal more. The usual advertising for GC is that it means you don't need to think about managing memory. It is still not "manual memory management" memory for objects is managed invisibly, and still without reference counting. That is typically unavoidable in Java, but not in non-GC languages.Īrena allocation, where memory in a subsystem is allocated using a specific allocator object, deallocation there is an in-line no-op, and all of subsystem memory is reclaimed en bloc at a chosen event boundary, is a common alternative where more control is needed. But automated memory management without reference counting is usual practice in a modern non-GC language.įreeing an array of objects only involves a series of calls to a deallocator when the array elements have pointers in them. Performance never matters except where it does. Reference counting is a form of GC to use when performance doesn't matter. The error in location estimation of the target due to sensor imperfections (limited angular resolution, clock jitter, athmospheric effects, etc etc) will be way larger than the 2 meter from the GC pause. Generation of the mid-course guidance updates is not nearly as time critical and won't suffer much from a 1 ms pause. The end-phase guidance and fuse timings are quite critical, as you say, but they are also not really under command of the CMS but rather done by embedded systems on board the missile. In the early and mid-phase guidance phases, the radar reflections from the target missile will not be strong enough for the relatively small receiver in the missile, so the system must depend on midcourse guidance updates (little bit to the right, little bit up, etc) from the combat management system on board the launching vessel to navigate to a "close enough" location from where the sensors on board the missile can acquire the target. But even the shorter range Sea Sparrow missiles that do behave as you describe use multiple guidance phases. I was a weapons engineering officer for the Dutch navy for 14 years I'm well aware of the mechanisms involved.įirst of all, a SM-2 will not use the flight path you describe as they tend to "dive down" on a sea skimming missile.
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