The address space executing an application program (a process or task) normally contains program instructions and data. Control blocks are NOT stored within the address space of the executing program. In which program address space will control block data be stored? (Hint: Which program is control of the managing executing applications? When you are working at your desk at work who is iin charge of managing your work schedule? )
The z/OS® and UNIX® are software of similar category.
The Task Control Blocks (TCBs) also known as Process Control Block which contains the process elements, created and managed by operating system, allow support for multiple process and containing the information needed to manage a particular process.
The typical Process Control Block (PCB) includes the Process State for running and waiting, Program Counter, CPU Registers, CPU Scheduling Information for process priority, Memory Management Information for values of base and limit registers, Accounting Information for process number and I/O status information for list of I/O devices allocated and list of open files.
Hence the Process Control Block of the Operating System manages and schedules the works.