Community resourceWorksheet

OCR H446 1.2.1 Systems software exam transition

Part 12 of 12 · H446 1.2.1 · Systems software

The assessment that closes H446 1.2.1. Nine original exam-style questions, worked independently, run across operating-system functions, paging and segmentation, virtual memory, interrupts, scheduling, classifications, BIOS and drivers, and virtual machines, finishing with a diagnose-and-repair question.

Students will:

  • explain operating-system functions with reference to a supplied shared-computer context
  • explain how virtual memory can make a heavily loaded laptop very slow
  • describe how the processor handles a higher-priority interrupt and returns to its program
  • match named scheduling algorithms to a print service and to an interactive system
  • identify and correct misconceptions that cut across several parts of the specification

Inside: 11 explanation cells, 1 multiple-choice question, 2 fill-in-the-blanks cells and 7 written answers. 47 marks, about 55 to 70 minutes.

Series: H446 1.2.1 · Systems software, part 12 of 12.

Shared by Coding PathwayVerified teacher

  • 21 cells
  • About 60 minutes
  • CC BY-SA 4.0
  • Shared 31 Aug 2026
  • Updated 3 Sept 2026

Preview

The whole resource, exactly as a class sees it. Answers and marking are held back.

Systems software exam transition

This is an original Paper 1-style assessment informed by OCR task forms, mark schemes and examiner commentary. It does not reproduce an official question.

Work independently. Use precise mechanisms, show schedule working on paper where useful and apply every explanation to the supplied context.

Question 1: operating-system functions

A community media centre has shared computers. Users log in with different permissions, edit large files and send work to several specialist devices.

Written answer4 marks

Explain two operating-system functions that are important in this media centre.

Choose functions that use the supplied context.

Students type their answer here.

Question 2: paging and segmentation

Fill in the blanks6 marks
Complete the comparison: paging uses entry 1-size divisions and can place them in entry 2 free locations recorded by a mapping. Segmentation follows entry 3 program sections whose sizes may be entry 4. Paging may waste space inside a final allocation, called entry 5 fragmentation; segmentation may leave separated free gaps, called entry 6 fragmentation.

Question 3: virtual memory

A laptop becomes very slow when several memory-intensive applications are open.

Written answer4 marks

Explain how virtual memory may cause this slowdown.

Use a complete causal sequence.

Students type their answer here.

Question 4: interrupts

Written answer5 marks

Describe how the CPU handles a higher-priority interrupt and returns to its current program.

Present the stages in order.

Students type their answer here.

Question 5: scheduling

A print service receives equal-priority jobs in arrival order. A separate interactive system must give every ready process regular access without estimating job lengths.

Multiple choice1 mark

Which pair of algorithms best matches the print service and interactive system, in that order?

  • ASRT and SJF
  • BRound robin and FCFS
  • CFCFS and round robin
  • DMLFQ and segmentation
Fill in the blanks5 marks
Three jobs are ready at time 0: A needs 7 ticks, B needs 2 and C needs 4. Under SJF the order is entry 1, entry 2, entry 3. If A has instead run for 3 ticks and then B arrives needing 2, SRT gives the CPU next to entry 4 because A has entry 5 ticks remaining.

Question 6: operating-system classifications

A network of dedicated flood-warning controllers shares sensor processing. An alarm must be produced within a guaranteed maximum time.

Written answer6 marks

Identify and justify three operating-system classifications relevant to the flood-warning system.

Use a different defining feature for each classification.

Students type their answer here.

Question 7: BIOS and device drivers

Written answer4 marks

Explain the purpose of the BIOS during start-up and the purpose of a device driver after the operating system is running.

Make the stages and mechanisms distinct.

Students type their answer here.

Question 8: virtual machines

A college wants to let students test several operating systems on one powerful server. It also uses a language that distributes intermediate code to different processor types.

Written answer6 marks

Explain both uses of virtual machines in this scenario, then discuss one benefit and one drawback of the server virtualisation.

Keep guest-OS virtualisation separate from intermediate-code execution.

Students type their answer here.

Question 9: diagnose and repair

Written answer6 marks

A response says: ‘When a real-time operating system receives an interrupt, it immediately runs the interrupt halfway through the instruction, then uses virtual storage as extra RAM.’ Identify and correct three misconceptions.

Write three separate corrections.

Students type their answer here.

Final review before hand-in

  • Functions are linked to effects and the supplied context.
  • Paging, segmentation and virtual memory remain distinct.
  • Interrupt stages preserve priority, stack state, PC and ISR order.
  • Every scheduling answer follows the named decision rule.
  • Classifications are features, can overlap and are not brands.
  • BIOS, drivers and virtual machines are placed at the correct abstraction and operating stage.