What is best-fit in operating system?

Answer 1

Best Fit

The allocator places a process in the smallest block of unallocated memory in which it will fit.

Problems:

• It requires an expensive search of the entire free list to find the best hole.
• More importantly, it leads to the creation of lots of little holes that are not big enough to satisfy any requests. This situation is called fragmentation, and is a problem for all memory-management strategies, although it is particularly bad for best-fit.

Solution:One way to avoid making little holes is to give the client a bigger block than it asked for. For example, we might round all requests up to the next larger multiple of 64 bytes. That doesn't make the fragmentation go away, it just hides it.

• Unusable space in the form of holes is called external fragmentation
• Unusable space in the form of holes is called external fragmentation

DGR