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1CP2-P-4.2 Process and memory management

Part 2 of 7 · 1CP2-P-4 · Operating systems and utilities

The scheduling and memory worksheet, explaining how one processor appears to run several programs at once.

Students will:

  • explain why an unfinished process returns to the queue
  • describe how scheduling makes processes appear to progress together
  • state accurately what virtual memory does
  • explain why excessive paging reduces performance
  • keep the terms program, process and file distinct

Inside: 5 explanation cells, 3 multiple-choice questions, 2 fill-in-the-blanks cells and 3 written answers. 16 marks, about 45 minutes.

Series: 1CP2-P-4 · Operating systems and utilities, part 2 of 7.

Shared by Coding PathwayVerified teacher

  • 13 cells
  • About 45 minutes
  • CC BY-SA 4.0
  • Shared 17 Aug 2026

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

Process and memory management

A stored program becomes a process when it is loaded into memory for execution. Several processes may be active, but CPU time and RAM are finite, so the OS must allocate both.

1. Share CPU time and main memory

Process and memory managementCPU schedulingprocess Aprocess Bprocess CCPU/coreone timeslotunfinished process returns to the queueMemory allocation and pagingRAMprocess Aprocess Bvirtual memorysecondary storagePaging moves sections when RAM is needed.

A scheduling algorithm prioritises waiting processes. On one processor core, one process has exclusive use at an instant. An unfinished process returns to a queue after its timeslot so another can run.

Current Pearson guidance does not require details of a named scheduling algorithm. Explain the queue, timeslot and prioritisation mechanism instead.

Fill in the blanks3 marks
A loaded running program is a gap 1. Waiting processes are held in a gap 2. A short allocation of CPU time is a gap 3.
  • page
  • process
  • queue
  • timeslot
Multiple choice1 mark

Why does an unfinished process return to the queue after its timeslot?

  • ATo give other active processes an opportunity to use the CPU
  • BTo convert it back into source code
  • CTo delete it from RAM permanently
  • DTo turn it into a peripheral
Written answer3 marks

Describe how scheduling can make several processes appear to progress on a single processor core.

Use queue, timeslot and switching.

Students type their answer here.

2. Allocate RAM and use virtual memory

The OS allocates each active process its own section of RAM. If RAM is needed, a paging algorithm can move a section between RAM and virtual memory, an area of secondary storage.

Virtual memory extends working space but is slower than RAM. It is not an extra physical RAM chip and does not permanently improve performance.

Fill in the blanks3 marks
The OS allocates processes sections of gap 1. Paging can move a section to gap 2, which is an area of gap 3.
  • RAM
  • CPU cache
  • secondary storage
  • virtual memory
Multiple choice1 mark

Which statement about virtual memory is accurate?

  • AIt is faster than RAM because it is permanent.
  • BIt is secondary-storage space used when RAM sections need to be moved.
  • CIt gives every process a separate CPU.
  • DIt stores only deleted files.
Written answer2 marks

Explain why excessive paging can reduce system performance.

Connect data movement and storage speed.

Students type their answer here.

3. Keep program, process and file distinct

A program file is persistent instructions on secondary storage. A process is an executing instance with allocated CPU time and memory. The same program can have more than one process, such as two open windows of an application.

Written answer2 marks

A computer opens two copies of the same drawing application. Explain how one program file can result in two processes.

Use persistent program, loaded instance and separate resources.

Students type their answer here.

Multiple choice1 mark

Which resource pair is central to process management?

  • ACPU time and main memory
  • BOptical discs and keyboards
  • CFilenames and folder colours
  • DASCII and hexadecimal

Route forward

You can explain scheduling, memory allocation, paging and virtual memory without unnecessary named-algorithm detail. Next you will follow communication between the OS and peripherals.