Two design variations which allow multiple processors to start up using a single ROM. In each design, a single, primary processor is allowed to perform a complete POST while the remaining, secondary processors are directed in the course of their POST to perform a more limited initialization sequence. At power on, the primary processor begins a normal POST, while the secondary processors are held until a vector is placed into a redirection vector location. Each secondary processor is then subsequently started, using its own initialization code located at the address indicated by the redirection vector. The first technique is applicable to general multiprocessor systems because the implementation of this design can be run either from external software or from an addition to the operating system of the particular machine on which it is being used. The second technique is more specifically oriented to a particular system, and includes the use of an identity register to differentiate between primary and secondary processors.