Subprocess construction

A general facility was provided for constructing a subprocess from a description in a given file. This description contained such information as entry point address, size of a scratch file, names of files to be used in map entries, etc. Various conventions were used to determine in which directory to look up a name. A special case of this facility accepted as input a subprocess descriptor (as described in chapter 10, ``The Disk/Directory System''). The command processor had had access to the action which converted the descriptor to a directory. The command processor then looked up a special name in the resulting directory, obtaining a file which it processed as above.