Abstract: An apparatus and method are provided for on-line code replacement of a program running in a process. The apparatus and method utilizes a variant of the exec system call, which will be referred to as a text-only exec. The present invention, utilizing a checkpoint methodology, allows the programmer maximum flexibility in addressing upgrade/replacement program issues and determines where, when and how the transition to a new version of a program should occur with least impact to the services.

Abstract: Apparatus and method are provided for transferring state data between computer software programs within the same software process. The apparatus and method does not require a special operating system, but instead only requires the use of a few standard operating system calls (i.e, fork and exec, etc.), so therefore is highly portable between different operating system machine types. The apparatus and method have complete flexibility to change arguments or return values and change calling order, function names, function code, and the like within the new version of the program.

Abstract: Apparatus and method are provided for on-line replacement of a program running in a process. The apparatus and method do not require a special operating system, but instead use a few standard operating system calls (i.e, fork and exec, etc.). Therefore, the apparatus is highly portable between different operating system machine types.