Chapter 17. Designing for robustness

Alloc heaven

One unusual turn of phrase I encountered, on joining the software development team at Psion in the late 1980s, was "alloc heaven". The term is still in common use in the development teams in Symbian, two decades later.

"Alloc" is short for "allocator" – the system that allocates cells of memory to pieces of software for their use. The idea is that pieces of software tell the allocator their memory requirements, use the memory cells provided by the system, and then, when finished with them, notify the allocator that the cells are free for reuse. If software neglects to inform the allocator that the cells are free, they remain out of bounds to other use. In Psion-speak, these cells have "died and gone to alloc heaven"; they never return. Even though these memory cells are no longer being used, other applications cannot get their hands on them.

Other companies use the phrase "memory leak" for the same phenomenon. When software misbehaves, memory leaks, and is lost from the main pool. Psion's term is more whimsical and, at the same time, denotes greater passion: it's tragic that the memory is no longer accessible. Because there has been so little memory on Psion mobile computers, Psion was passionate about not wasting that memory. The same is true on smartphones.

A hallmark of a passion, as opposed to a mere intellectual notion, is that it motivates real action. The creators of Symbian OS were sufficiently passionate about not wasting memory ...

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