> Are there really no instances of rewrites succeeding? The most famous instance of a successful rewrite was IBM's transition to OS/360 [1] in the 1960s, which

> Are there really no instances of rewrites succeeding? The most famous instance of a successful rewrite was IBM's transition to OS/360 [1] in the 1960s, which was not just a complete rewrite but a completely new system to replace all the previous ones. (The "360" comes from the number of degrees in a full turn.) Who spearheaded this huge effort? A certain Frederick P. Brooks, who used his experience with the project to write _The Mythical Man Month_, which coined the term "second-system effect" [3]. Of course, while the 360 project was _ultimately_ successful, they made all the now-familiar mistakes that Brooks documented in his book -- it was an extremely expensive and time-consuming project that was only possible thanks to IBM's enormous resources and strong leadership. --- [1] http://www-01.ibm.com/software/os/systemz/pdf/360Revolution_0406.pdf http://www-01.ibm.com/software/os/systemz/pdf/360Revolution_... [2] http://en.wikipedia.org/wiki/The_Mythical_Man-Month http://en.wikipedia.org/wiki/The_Mythical_Man-Month [3] http://en.wikipedia.org/wiki/Second-system_effect http://en.wikipedia.org/wiki/Second-system_effect