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OCR H446 1.2.1 Systems software consolidation

Part 11 of 12 · H446 1.2.1 · Systems software

A consolidation worksheet that interleaves the whole of H446 1.2.1 instead of revisiting topics one at a time, so memory management, interrupts, scheduling, classifications and virtualisation all appear inside the same systems. It is built to reveal the one mechanism or distinction that needs repair before exam practice begins.

Students will:

  • separate scattered free memory from insufficient RAM when both appear in one system
  • order the stages that follow acceptance of a higher-priority interrupt
  • compare round robin with a multi-level feedback queue and recommend one for a mixed workload
  • place the BIOS, a device driver and an operating-system virtual machine at the correct stage
  • assess the risk of relying on virtual machines and virtual memory together on one host

Inside: 5 explanation cells, 4 multiple-choice questions, 3 fill-in-the-blanks cells and 4 written answers. 43 marks, about 45 to 60 minutes.

Series: H446 1.2.1 · Systems software, part 11 of 12.

Shared by Coding PathwayVerified teacher

  • 16 cells
  • About 45 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 consolidation

This worksheet interleaves the ideas from SS01 to SS10. It is designed to reveal which distinction or mechanism needs repair before examination practice.

No major content is introduced. Work without looking back first, then use the error clinic to choose a focused worksheet for correction.

Review your responses

Use the evidence in your completed responses to identify the first model, state transition or reasoning link that needs improvement. Correct that point, then reapply it to the changed context.

Multiple choice1 mark

An operating system prevents two applications from writing into the same allocated area of RAM. Which function is most direct?

  • AFile management
  • BUser interface
  • CMemory management
  • DBIOS configuration
Fill in the blanks7 marks
Pages are entry 1-sized divisions; segments follow entry 2 program sections. Virtual memory supplements entry 3 using secondary storage. An interrupt is a entry 4, while its ISR is executable entry 5. A real-time OS guarantees a response before a entry 6. A device driver supplies hardware-specific entry 7.
Written answer6 marks

A graphics workstation has enough total free memory, but the free areas are scattered, and it also begins using secondary storage because active demand exceeds RAM. Explain the two different memory-management problems and mechanisms present.

Separate fragmentation/allocation from virtual-memory swapping.

Students type their answer here.

Multiple choice1 mark

Which sequence fragment is correct after a higher-priority interrupt is accepted?

  • ARun the signal, erase registers, restart the computer
  • BMove all RAM to storage, then perform POST
  • CPlace the ISR in a printer queue
  • DSave register state, set PC to the ISR, run it, restore state
Fill in the blanks4 marks
Process A arrives at time 0 needing 8 ticks. It has run for 3 ticks when B arrives needing 2 ticks. Under SJF, A normally entry 1 because the algorithm is entry 2. Under SRT, entry 3 runs next because its requirement is shorter than A's entry 4 ticks remaining.
Written answer6 marks

A server handles short interactive requests and long background conversions. Compare round robin and MLFQ, then recommend one for the workload.

Discuss mechanism, responsiveness, treatment of long work and one trade-off.

Students type their answer here.

Multiple choice1 mark

A dedicated railway controller must respond within a guaranteed maximum time and coordinates several trackside computers. Which pair is best supported?

  • AReal time and distributed, with embedded also plausible
  • BEmbedded and real time only
  • CMulti-user and FCFS
  • DBIOS and virtual memory
Written answer6 marks

For each item, state its role and place it in the correct stage or abstraction: BIOS, device driver and operating-system virtual machine.

Write three distinct explanations rather than saying each 'controls hardware'.

Students type their answer here.

Multiple choice1 mark

Which statement contains a misconception?

  • AVirtual memory uses storage to supplement limited RAM
  • BVirtual storage and virtual memory are interchangeable names
  • CA virtual machine can provide a guest OS with virtual hardware
  • DA software VM can execute intermediate code
Written answer6 marks

A school wants isolated training servers on one host, but the host has limited RAM. Explain how virtual machines and virtual memory could both be involved, and assess one risk of relying heavily on this design.

Keep the two virtual concepts separate and link them causally.

Students type their answer here.

Error clinic

Before the checkpoint, inspect these high-frequency weaknesses from OCR assessment:

  1. Have you linked a function to a consequence rather than repeated its name?
  2. Have you connected virtual memory to moving pages between RAM and storage?
  3. Does the interrupt wait for a cycle boundary and priority decision?
  4. Have you kept SJF non-pre-emptive and SRT pre-emptive?
  5. Does MLFQ contain several queues and feedback movement?
  6. Have you named an OS classification rather than a brand?
  7. Have you separated virtual memory, virtual storage and virtual machines?

Closed-book checkpoint

Complete the integrated reasoning chain. Checking is held for teacher review.

Fill in the blanks4 marks
Strong systems-software answers state a mechanism, connect it to a system entry 1 and then explain the resulting entry 2 in context. When comparing, use a shared entry 3. When recommending, acknowledge a relevant entry 4 before reaching a judgement.

Review your understanding

Before submitting, check that you can explain the main distinction in your own words, apply it in an unfamiliar context and justify each consequence rather than only naming a feature.