methods for implementing rejuvenation are: Time based rejuvenation Prediction based rejuvenation Memory bloating Garbage collection is a form of automatic memory management whereby the system automatically recovers unused memory. For example, the .NET Framework manages the allocation and release of memory for software running under it. But automatically tracking these objects takes time and is not perfect. .NET based web services manage several logical types of memory such as stack, unmanaged and managed heap (free space). As the physical memory gets full, the OS writes rarely used parts of it to disk, so that it can reallocate it to another application, a process known as paging or swapping. But if the memory does need to be used, it must be reloaded from disk. If several applications are all making large demands, the OS can spend much of its time merely moving data between main memory and disk, a process known as disk thrashing. Since the garbage collector has to examine all of the allocations to decide which are in use, it may exacerbate this thrashing. As a result, extensive swapping can lead to garbage collection cycles extended from milliseconds to tens of seconds. This results in usability problems. See also Software regression Software rot References Further reading R. Matias Jr. and P. J. Freitas Filho, "An experimental study on software aging and rejuvenation in web servers," Proceedings of the 30th Annual International Computer Software and Applications Conference (COMPSAC'06), Vol. 01, pp. 189 – 196, 2006. M. Grottke, R. Matias Jr., and K. S. Trivedi, "The Fundamentals of Software Aging," Workshop of Software Aging and Rejuvenation (WoSAR/ISSRE), 2008. R. Matias Jr, P. Barbetta, K. Trivedi, P. Freitas Filho "Accelerated Degradation Tests Applied to Software Aging Experiments," IEEE Transactions on Reliability 59(1): 102–114,2010. M. Grottke, L. Li, K. Vaidyanathan, and K.S. Trivedi, "Analysis of software aging in a web server," IEEE Transactions on Reliability, vol. 55, no. 3, pp. 411–420, 2006. M. Grottke, K. Trivedi, "Fighting Bugs: Remove, Retry, Replicate, and Rejuvenate," IEEE Computer 40(2): 107–109, 2007. More papers on Proceedings of Workshop of Software Aging and Rejuvenation (WoSAR'08,'10, '11, '12, '13, '14) at IEEE Xplore. Software anomalies