1. Programming method, interface mechanism of parallel running tasks, script computer language, visual computer language, extension to existing computer language, compiler apparatus, any of them defining parallel execution through program subroutines comprising: (a) a part that only a single task can be executing at a given moment with the remaining part, if any, being allowed to be executed by plurality of running tasks at the same time; (b) a lock variable or data structure, automatically generated by the compiler or assigned to one said subroutine or set of them, managing exclusive execution of part (a) allowing only one task to execute above part (a) at the same given moment while suspending and queuing or otherwise constraining for a time being other tasks attempting execution of said part (a); whereby complex computing jobs are broken down into plurality of such relatively small subroutines executing in parallel and synchronized through limited access to above described exclusive parts (a) of subroutines.