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Unit 3: Using Operating System

The operating system must try to satisfy these requests in a multi-user, multi-process environment Notes
while managing-

• Resource allocation
• Error Detection
• Protection

1. The Operating System: Process Control
A process is the unit of work. Processes need to be able to control their own execution, as
well as spawn new processes to perform tasks concurrently. Processes request services to:
• fork: create a new process

• exit: normal termination, abort: abnormal termination
• execve: load and execute another program
• wait: wait for another process to finish

• Signal Management: handling asynchronous events
— signal, sigaction: setting signal handlers

— kill: sending signal
• Threads: creating and managing multiple execution threads in a single process

Figure 3.2

Process State Transition Diagram

New Terminated
Exit
Admitted
Ready Dispatch Running
I/O or event
completion I/O or
wait event
Blocked

Ready queue
Processor

Blocked queue

2. The Operating System: File System Management

The User sees . . .

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