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C# Memory Leak Torpedoed Princeton's DARPA Chances
nil0lab writes "In a case of 20/20 hindsight, Princeton DARPA Grand Challenge team member Bryan Cattle
reflects on how their code failed to forget obstacles it had passed. It was written in Microsoft's C#, which isn't supposed to let you have memory leaks. 'We kept noticing that the computer would begin to bog down after extended periods of driving. This problem was pernicious because it only showed up after 40 minutes to an hour of driving around and collecting obstacles. The computer performance would just gradually slow down until the car just simply stopped responding, usually with the gas pedal down, and would just drive off into the bush until we pulled the plug. We looked through the code on paper, literally line by line, and just couldn't for the life of us imagine what the problem was.'"
This is a stupid, stupid article headline. Of course you can have a memory leak in a managed language! Any Java programmer who's decent understands that.
.NET CLR did its job, just like it was supposed to.
It's not C#'s fault. The team had references to the obstacle list (event handlers), which prevented garbage collection. The
The sad thing is that Microsoft offers a perfectly servicable profiler for free that can be used on any C# application and is better than most commercial native Win32 profilers...
using namespace slashdot;
troll::post();
(1) You are supposed to test your software.
(2) You are particularly supposed to test your software if you send $200k and 1 ton of hardware careening through the street on autonomous real-time control.
(3) Garbage collectors do not prevent memory leaks.
(4) Garbage collected systems can be good for building real-time systems, but you need a real-time garbage collector or you need to treat the system as if it didn't have a garbage collector at all.
What "ruined their chances" was not that they overlooked a memory leak, what ruined their chances was that they didn't know what they were doing.
Weak references also incur the overhead of a check on every call to ensure the object hasn't been cleaned up. This was sloppy, poorly tested code. The engineers on it made a mistake and caught it too late. It happens.
The poster of the article was trolling, and not only trolled with the post, managed to get a troll posted to a slashvertisement which was not even trolling.
Impressive on the part of the person who submitted it, but disappointing considering Taco's comments a few weeks back about articles that are truly nothing but advertisements.