Computer Science:Education

McCabe's cyclomatic complexity is calculated by measuring the number of linearly independent paths through the program. The higher the number the more complex the code. It is a software metric developed by Thomas J. McCabe , Sr. in 1976. A Software metric is defined as a quantitative measure of an attribute a software system has with respect to Cost, Quality, Size and Schedule. Cyclomatic Complexity can prove helpful for developers and testers to determine independent path executions to assure that all the paths have been tested at least once, to focus more on the uncovered paths, to improve code coverage, evaluate the risk associated with the program, etc. Clearly, Cyclomatic complexity is useful in White Box/Structured Testing. Cyclomatic complexity is given by: Cyclomatic complexity = e - n + 2p Where: p= number of disconnected paths of the flow graph of a calling program and a function/module n= number of vertices e= number of edges Examples: ...

In computer systems using Paging, Page replacement algorithms are used to decide which pages to swap out. A Page fault is a trap by hardware to the software that arrises when a page is mapped by virtual address is not present in physical location. Pages are swapped out only when a page fault occurs. There are various Page Replacement Techniques consisting of RAND,Optimal,FIFO,LRU,NRU,FIFO Second Chance,Enhanced FIFO Second Chance,Working Set,PFF to name a few. We can list various goals of Page Replacement Algorithms such as a.Simplify things for OS implementer. b.Minimize the number of page faults c.Reduce the overheads for page faults when they occur d.Minimize CPU time of algorithm