Karteikarten
Chapter 3 Review Questions
Karten in diesem Stapel (14)
- 1What is an instruction trace?Sequence of instructions executed for a process.
- 2Explain the concept of a process and mark its differences from a program.A process executes instructions on the processor. A program is a set of instructions that are executed by one or many processes.
- 3For the processing model of Figure 3.6 briefly define each state.Running: process is currently running.
Ready: process is waiting to be executed.
Blocked: process cannot be executed (waiting for I/O).
New: process just created, not been added to memory.
Exit: process finishes or is aborted. - 4What does it mean to preempt a process?To move process from running state, on interrupt (clock, I/O etc.).
- 5What is process spawning?When a process creates a child process.
- 6Why does Figure 3.9b have two blocked states?It has a special state for suspended processes. It is so that if process was swapped out of memory, while in blocked state, that it is not swapped back in to memory when it is still waiting for the resources it was initially waiting for.
- 7List four characteristics of a suspended process.1. The process is not immediately available for execution.
2. The process may or may not be waiting on an event.
3. The process was placed in a suspended state by an agent: either itself, a parent process, or the OS, for the purpose of preventing its execution.
4. The process may not be removed from this state until the agent explicitly orders the removal. - 8For what types of entities does the OS maintain tables of information for management purposes?memory, I/O, file, and process
- 9What are the elements of a process image?User data, user program, stack and process control block.
- 10Why are two modes (user and kernel) needed?The two modes are needed for security reasons. The kernel mode has access to more lower level operations on e.g. registers, I/O and memory.
- 11Identify some situations where a parent process may terminate the execution of its child.Parent process may terminate child process at any time. It may do that when the child process is non-responsive or when the parent process is terminated.
- 12What is the difference between an interrupt and a trap?A trap is when the OS determines that the interrupt is fatal and terminates the process.
- 13What are the advantages of a process-based operating system?This approach has several advantages. It imposes a program design discipline that encourages the use of a modular OS with minimal, clean interfaces between the modules. In addition, some noncritical operating system functions are conveniently implemented as separate processes.
- 14What is the difference between a mode switch and a process switch?In mode switch there is no change in the current process state, and the OS runs its operations to check for instance if there are any interrupts. In process switch he has to to change the process control block of the running process and load the next process.
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- Bachillerato Computer Science (Fundamentals of Operating Systems) Karteikarten am Chapter 3 Review Questions, erstellt von Kristján Ólafsson am 15/04/2016.
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- Kristján Ólafsson
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