We propose several modifications to the binary buddy system for managing dynamic allocation of memory blocks whose sizes are powers of two. The standard buddy system allocates and deallocates blocks in Θ(lg n) time in the worst case (and on an amortized basis), where n is the size of the memory. We present three schemes that improve the running time to O(1) time, where the time bound for deallocation is amortized for the first two schemes. The first scheme uses just one more word of memory than the standard buddy system, but may result in greater fragmentation than necessary. The second and third schemes have essentially the same fragmentation as the standard buddy system, and use O(2 (1+ √ lg n) lg lg n) bits of auxiliary storage, which is ω(lg k n) but o(n ε) for all k ≥ 1 and ε> 0. Finally, we present simulation results estimating the effect of the excess fragmentation in the first scheme.

This memory is recognized by the BIOS as PCI device DMAable memory. It is also mapped in the physical memory and can be accessed by the operating system as regular memory

Garbage collection (GC) plays a more and more dominant role in the landscape of modern computer science languages. Coupled with a proper object oriented language GC can help the developer to focus on the true problem domain, leaving the details of memory deallocation to a system cleanup process. However, the transition to a GC collected language might introduce new areas of problems, both in terms of application performance and scalability. This article will aim at describing these positive and negative effects of using a GC language. It will also illuminate the strong and weak side of both GC and non-GC language in such a way that a developer will have a clear understanding of the two alternatives.