| Abstract: | The usual way of installing a new version of a piece of software is to shut down the running program and then install the new version. This necessitates a sometimes unacceptable delay during which service is denied to the users of the software. An on-line software replacement system replaces parts of the software while it is in execution, thus eliminating the shutdown. In this paper, we describe a system for on-line software version change for software written in the C language. When the change is initiated by the user, the system instantiates a new process with the new version of the software, transfers state from the old process to the new one at an appropriate time, and transfers the control to the new process. The user sees a minimal delay in this switchover. |
