A1.3 Operating systems and control systems questions for IB Computer Science
65 questions on Operating systems and control systems, written by Augment in the style of IB exam papers. Six of them are below in full, to answer on paper.
- IB Computer Science
- Part of A1 Computer fundamentals
- SL and HL
Questions by paper and level
SL and HL questions are for students at either level. HL only questions cover what only HL students study.
| Paper | SL and HL | HL only | All |
|---|---|---|---|
| Paper 1 | 40 | 25 | 65 |
Counted on
Questions to try
Written by Augment in the style of IB exams, not past papers. Answer them on paper, then check each one against its markscheme with a free account.
A medical company is developing the software for an infusion pump that delivers drugs to hospital patients at a precise rate. One engineer proposes writing the control software in an interpreted scripting language so that it can be updated easily; another insists it must be compiled.
Discuss which translation method should be used for the pump's control software.
6 marks
A company builds smart televisions. Its developers write streaming and gaming apps that run on top of the television's operating system (OS), and the same apps must run on several models with different processors, memory sizes and remote-control receivers.
- (a)
State two hardware resources that the television's OS manages.
2 marks
- (b)
Describe how the OS hides the complexity of the hardware from the app developers.
3 marks
Nurses at a hospital use shared workstations on every ward. Many different applications run at the same time, including a patient-records program, a drug-prescribing program and a messaging app.
- (a)
Describe two functions of the workstation's operating system, other than scheduling, that support the nurses' work.
4 marks
- (b)
Outline how the accounting function of the OS could help the hospital's IT department.
2 marks
A print shop sends four jobs to its colour printer's controller. The controller runs one job at a time using first-come first-served (FCFS) scheduling. All four jobs arrive at time 0 in the order J1, J2, J3, J4.
Job | Arrival time (s) | Processing time (s) |
|---|---|---|
J1 | 0 | 12 |
J2 | 0 | 3 |
J3 | 0 | 5 |
J4 | 0 | 2 |
The waiting time of a job is the time between its arrival and the moment it starts.
- (a)
Calculate the waiting time of each job, and the average waiting time, under FCFS.
3 marks
- (b)
The jobs had instead arrived in the order J4, J2, J3, J1. Calculate the new average waiting time under FCFS.
2 marks
- (c)
Explain why FCFS can give a poor average waiting time, using your answers to parts (a) and (b).
3 marks
A shared laboratory computer in a university runs three processes that are all ready at time 0, queued in the order A, B, C. It uses round robin scheduling with a time quantum of 4 ms. Ignore the time taken for context switches.
Process | Arrival time (ms) | CPU time needed (ms) |
|---|---|---|
A | 0 | 10 |
B | 0 | 4 |
C | 0 | 7 |
- (a)
Construct a Gantt chart (a timeline showing which process runs in each interval) for this round robin schedule.
3 marks
- (b)
Calculate the waiting time of each process, where waiting time = finish time − arrival time − CPU time needed.
3 marks
- (c)
Students use this computer interactively. Compare round robin with first-come first-served (FCFS) scheduling for this use.
3 marks
A ride-share company's dispatch server runs four processes. Each has an arrival time, a CPU burst time and a priority, where 1 is the highest priority.
Process | Arrival time (ms) | Burst time (ms) | Priority |
|---|---|---|---|
P1 | 0 | 5 | 3 |
P2 | 1 | 3 | 1 |
P3 | 2 | 6 | 4 |
P4 | 4 | 2 | 2 |
For every calculation: turnaround time = finish time − arrival time, and waiting time = turnaround time − burst time. Ignore context-switch time.
- (a)
State what is meant by scheduling in an operating system.
1 mark
- (b)
Calculate the average waiting time if the server uses first-come first-served (FCFS) scheduling.
3 marks
- (c)
The server now uses round robin with a time quantum of 3 ms. A process that arrives at the moment another's quantum ends joins the queue before the pre-empted process.
Calculate the average waiting time, showing your timeline.
4 marks
- (d)
The server now uses non-preemptive priority scheduling.
Calculate the average waiting time.
3 marks
- (e)
Explain one problem that priority scheduling could cause on a busy dispatch server, and how it could be reduced.
3 marks
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More questions in Computer fundamentals
- A1.1Computer hardware and operation
- A1.2Data representation and computer logic
- A1.3Operating systems and control systemsThis page
- A1.4TranslationHL only
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