Process Management Exam Questions

• D Time slice (1)
• The only correct answer is D. The correct answer is time slice.
• A is not correct because a process is a program that is being run
• B is not correct because round robin is a scheduling method that takes turns, not the period of CPU time itself
• C is not correct because a scheduler decides which process runs next

• A Multitasking (1)
• The only correct answer is A. The correct answer is multitasking. Allow 'multi-tasking'.
• B is not correct because process management is the wider operating system function that controls processes, not the term for running more than one task at the same time
• C is not correct because a scheduler decides which process will run next on the CPU
• D is not correct because a time slice is a fixed period of CPU time allocated to a process by the scheduler

• C Scheduler (1)
• The only correct answer is C. The correct answer is scheduler.
• A is not correct because an interrupt is a signal that needs immediate attention
• B is not correct because a process is a program that is being executed, not a component of the operating system
• D is not correct because a time slice is the amount of CPU time a process is given, not what decides which process runs next

Award one mark for any of the following up to a maximum of two marks:

• A program/set of instructions (1)
• That is being run/executed (1)
• That has been loaded into RAM/main memory to be run (1)
• That the operating system manages/schedules (1)

Allow 'task' as a synonym for process.

Accept 'executed by the CPU'; naming the CPU is not required.

For 'loaded into RAM/main memory', the answer must say the program is there to be run/executed; saying only that it is 'stored in memory' earns no mark.

Do not accept 'a program'/'a set of instructions' on its own as a full definition; it earns the first mark only.

Do not accept a program stored on secondary storage/a hard disk that is not running.

Do not accept a description of the CPU or the fetch-decode-execute cycle.

Do not accept 'a thread' as a definition of a process.

Award one mark for any of the following up to a maximum of two marks:

• Creates one or more process(es) (1)
• Moves/loads the program instructions into RAM, so that the process is ready (1)
• Schedules the process/decides when it will next run on the CPU (1)
• Allocates CPU time/a time slice to the process (1)
• Sets the process state to ready/places the process in the ready queue (1)
• Allocates resources, such as memory or a peripheral, to the process (1)

Allow 'program' instead of 'process'.

Each mark must be for a different action: do not award both 'schedules the process' and 'sets the state to ready/ready queue' for one description of deciding when the process will run.

Do not award the 'allocates resources' point for a statement that has already earned the 'creates a process' point, e.g. 'allocates memory to create the process'.

Do not accept 'opens the program' or 'the program runs', as these repeat the question.

Do not accept storing the program on the hard drive, as this is file management.

Do not accept a description of the fetch-decode-execute cycle or of multitasking on its own, as neither names an action the operating system takes.

Award one mark for any of the following up to a maximum of two marks:

• The operating system manages/runs more than one process/task/program at the same time (1)
• More than one process/task/program appears to run at the same time (1)
• Each process/task/program is given a time slice of CPU time/a share of CPU time (1)
• The operating system switches between processes/tasks/programs (1)
• The operating system decides which process/task/program will run next (1)

Award a maximum of one mark for stating that more than one process/task/program is managed/run (or appears to run) at the same time.

Award a maximum of one mark for stating how CPU time is shared or switched between processes/tasks/programs.

Do not accept using more than one CPU/processor to run a single program.

Do not accept 'running many programs' on its own; it must say they are managed/run at the same time.

Award up to two marks for a linked description such as:

• Decides which process is given use of the CPU (1) so that more than one program can run/appear to run at the same time (1)
• Allocates CPU time to each process (1) so that no single process takes control of the CPU (1)
• Manages the states/life-cycle of each process (1) so processes can be moved between ready/running/blocked (1)
• Keeps track of the processes and their status (1) so a process waiting for a resource can be returned to the CPU when it is ready (1)

Do not accept responses that only describe what a process is.

Do not accept responses that only list the types of operating system management.

Award up to two marks for a linked description such as:

• Allocates memory/RAM to the process (1) so its instructions and data can be stored (1)
• Loads/moves the program instructions into RAM (1) so the process is ready to run (1)
• Adds the process to the ready queue (1) so it can be scheduled onto the CPU (1)
• Gives the process a process ID (PID)/identifier (1) so the operating system can track/manage it (1)

For both marks, the development must follow/be linked to the point.

Only award one of the first two bullets in any one response; allocating memory and loading into RAM are the same stage.

Accept 'memory' for 'RAM' and vice versa.

Accept 'added to a queue for the processor' for the ready queue point.

Do not accept responses that say the process is run on the CPU straight away.

Do not accept descriptions of the program executing/running its instructions, or of the program file being created/saved.

Do not accept responses about the process being blocked or terminated.

Award up to two marks for a linked description such as:

• Frees/releases the memory/RAM used by the process (1) so other processes can use it (1)
• Removes the process from the ready queue/scheduler (1) so it is no longer selected to run on the CPU (1)
• Releases other resources (files/peripherals) held by the process (1) so they can be used by other processes (1)
• Removes/updates the process entry in the process table (1) to show the process is no longer running (1)

Allow 'process queue' / 'queue of processes' for ready queue/scheduler.

Allow 'program' for process.

Do not accept responses that only restate that the process/program has ended/closed.

Do not accept responses that only say the process stops running / the computer stops using the program, with no linked description.

Do not accept responses that say the program/file is deleted from storage or that the user closed/deleted the program.

Award up to two marks for a linked explanation such as:

• The CPU can only execute one process at a time (1) so the operating system must decide which process runs next (1)
• Each process needs CPU time (1) so the operating system must share the CPU between processes (1)
• One process could use the CPU for too long (1) so the operating system must give other processes a turn (1)
• A process may be waiting for a resource or user input (1) so the operating system can run another process that is ready (1)
• The user wants to run more than one program (1) so the operating system must manage which process uses the CPU and when (1)

For both marks, the expansion must follow/associate with the statement.

Allow 'program' for 'process'.

Do not accept 'to manage processes' / 'so processes are managed' without a reason.

Do not accept answers about managing files, memory or peripherals.

Award up to two marks for a linked explanation such as:

• The operating system switches rapidly between processes (1) so each process runs for a short time slice before the next one starts (1)
• Each process is given a small amount of CPU time (1) so the CPU moves on to another process when that time is up (1)
• The operating system chooses which process to run next (1) so the CPU is shared between the programs (1)
• Processes take turns to use the CPU (1) because the CPU is so fast the user does not notice the switching (1)
• Only one process can run on the CPU at a time (1) so the operating system must swap processes in and out quickly (1)

For both marks, the expansion must follow/associate with the statement.

Allow 'time slice' / 'time quantum'.

Do not accept 'the computer has more than one CPU' / 'each program runs on its own CPU'.

Do not accept 'the CPU does two things at once' without saying processes take turns/are switched.

Award up to two marks for a linked explanation such as:

• A process is created for the program (1) so that its instructions can be loaded into RAM (1)
• The process is put into the ready state (1) so that it can wait for the CPU to become available (1)
• The operating system adds the process to a queue of ready processes (1) so the scheduler can choose it when the CPU is free (1)
• The operating system allocates the resources the process needs (1) so that it can start running when it is given CPU time (1)

For both marks, the expansion must follow/associate with the statement.

Allow 'main memory' for RAM.

Do not accept 'the browser is downloaded/loaded from the internet'.

Do not accept 'the program is run immediately on the CPU' without the ready step.