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Unit 4: Process Management
Figure 4.11: Detail Diagram of a Kernel Thread Notes
Process + Thread Process + Thread
Virtual Layout Creation
TSIDL
Thread scheduling
TSRUN
Process + Thread
TSRUNPROC Termination
TSZOMB
TSSLEEP
Because of the compromises involved in each of these two approaches to threading, some systems
use a hybrid approach in which both user-level and kernel-supported threads are implemented.
Solaris 2 is such a system. A diagrammatic approach of hybrid thread is mentioned in
Figure 4.12.
Figure 4.12: Hybrid Thread
Process
runtime
mapping
user-level thread
kernel entity
4.9 Multi-threading
When the computers were first invented, they were capable of executing one program at a time.
Thus once one program was completely executed, they then picked the second one to execute and
so on. With time, the concept of timesharing was developed whereby each program was given
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