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OCR H446 1.2.2 Interpreters, compilers and assemblers

Part 3 of 7 · H446 1.2.2 · Applications generation

Assemblers, compilers and interpreters are separated in H446 1.2.2 by their input, the moment translation happens, what they produce and whether that output can be reused. This worksheet traces all three routes alongside each other so that students offer a benefit with a consequence rather than a restated feature.

Students will:

  • trace assembly source and high-level source along their different translation routes
  • state compiler and interpreter differences by comparing the same criterion on both sides
  • explain a development benefit of interpreting and a distribution benefit of compiling
  • choose a translation route from stated project constraints and justify it
  • recognise where the simplified examined model differs from real translator behaviour

Inside: 5 explanation cells, 1 multiple-choice question, 2 fill-in-the-blanks cells and 5 written answers. 38 marks, about 45 to 55 minutes.

Series: H446 1.2.2 · Applications generation, part 3 of 7.

Shared by Coding PathwayVerified teacher

  • 13 cells
  • About 45 minutes
  • CC BY-SA 4.0
  • Shared 31 Aug 2026
  • Updated 3 Sept 2026

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

Interpreters, compilers and assemblers

Three routes, two source levels

Three directional translator routesThree routes from source to processor-executable instructions assembly sourceprocessor-specificmnemonics and operandsassemblermachine codeone mnemonic to onemachine instruction model high-level sourcehuman-readablelanguage abstractioncompilerexecutabletranslated before useand available to run again high-level sourcesource and inputsavailable at run timeinterpreterexecutiontranslation happensduring each run OCR assessment comparison modelModern implementations may mix techniques; compare the stated models.

A processor executes machine instructions, so source must be translated. An assembler accepts assembly source. A compiler and interpreter accept high-level source but differ in OCR's assessment model in when translation occurs and what reusable output remains.

Fill in the blanks3 marks
Assembly language is translated by an gap 1. A gap 2 translates a high-level program before execution and can produce reusable executable code. An gap 3 translates during execution and the source is translated again on a later run.
  • assembler
  • compiler
  • interpreter
  • loader

Matched comparison and benefit

  • Feature: compiler translates the program before execution; interpreter translates during execution in OCR's model.
  • Benefit chain: interpreted execution can stop at the encountered error -> the developer sees the point reached -> small changes can be tested/debugged quickly.
  • Deployment chain: compiler creates reusable executable code -> no retranslation each run -> distribution can hide source and runtime can be faster.

A feature becomes a benefit only when its consequence is stated.

Multiple choice1 mark

Which response states a compiler benefit rather than only a feature?

  • AIt compiles
  • BIt translates the whole program
  • CIt creates reusable executable code, so users need not retranslate the source each time
  • DIt uses source code
Written answer4 marks

Explain two differences between compiler and interpreter in OCR's model. For each difference, compare the same criterion on both sides.

Use translation timing, executable/retranslation, error behaviour or source distribution.

Students type their answer here.

Written answer8 marks

State and explain two benefits of an interpreter during development and two benefits of a compiler when distributing a finished application.

Every answer needs feature -> consequence -> context.

Students type their answer here.

Written answer5 marks

A student says: ‘assembly is low level, so a compiler or interpreter changes it into machine code.’ Correct the explanation and compare the assembler route with high-level translation.

Retrieve the language boundary without reteaching assembly programming.

Students type their answer here.

Apply the model independently

The remaining tasks change the context or reduce the support. Complete them without copying the worked model, then check that each explanation connects a mechanism to its consequence.

Written answer9 marks

Choose and justify a translation route for (1) a classroom script being changed and tested repeatedly, (2) a commercial desktop program distributed without source, and (3) processor-specific assembly for a controller.

Name input, translator, output/execution behaviour and contextual benefit.

Students type their answer here.

Written answer4 marks

Explain why ‘an interpreter always works literally one source line at a time’ and ‘a compiler finds every error’ are unsafe real-world claims, while preserving the simplified OCR comparison model.

Use ‘in OCR's model’ and distinguish an assessment contrast from every implementation.

Students type their answer here.

Fill in the blanks4 marks
A translator converts source into checkpoint gap 1 instructions or an executable route. Assembly uses an checkpoint gap 2. Compiler/interpreter comparisons need the same checkpoint gap 3 and benefits need a stated checkpoint gap 4.

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.