IGCSE Computer Science: Software — Practice Questions (Cambridge 0478)

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs — Cambridge International holds copyright in its own papers. Use these alongside the official past papers available free from your board.

Related: Software study guide and revision notes

This set practises every learning outcome in Topic 4 of the Cambridge IGCSE Computer Science 0478 syllabus (2026–2028): software types and the operating system (4.1) and programming languages, translators and IDEs (4.2). Topic 4 is examined on Paper 1, where calculators are not allowed and answers are short and precise.

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Section A

1. Tick (✓) one box in each row to show whether the software is system software or application software. [4]

Software	System software	Application software
Photo-editing program
Anti-virus utility
Operating system
Spreadsheet

2. Complete the sentences using words from the list. Not all words are used. [3]

application · bootloader · compiler · firmware · hardware · operating system

Applications are run on the …………………… . The operating system is run on the …………………… . The bootloader is run on the …………………… .

3. State what is meant by a mnemonic in assembly language, and name the translator that converts an assembly language program into machine code. [2]

Section B

4. A hospital laptop is used by several nurses during each shift. Each nurse logs in with their own username, and patient records are saved in folders on the laptop.

Identify three functions of the operating system that are used in this situation. For each, describe how it is used. [6]

5. A program calculates the average waiting time at a clinic. When no patients have been seen, the program tries to divide by zero.

(a) State whether this is a hardware interrupt or a software interrupt. [1] (b) Give one other example of the same type of interrupt. [1] (c) Describe how the processor handles the interrupt. [4]

6. A programmer is writing software to control the motor in a robotic vacuum cleaner. She is deciding between a high-level language and a low-level language.

(a) Explain one reason why a low-level language might be chosen for this program. [2] (b) Explain two disadvantages of using a low-level language rather than a high-level language. [4]

7. A student translates a 400-line program. The translator produces a report listing seven syntax errors on different lines, and no executable file is created until all seven are fixed.

(a) Identify the type of translator used. Give a reason for your answer. [2] (b) Describe how the result would be different if the other type of high-level language translator had been used. [3]

8. A school’s programming club uses an IDE.

(a) Describe what each of these IDE functions does: auto-completion, prettyprint and run-time environment. [3] (b) Explain how auto-correction differs from error diagnostics. [2]

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Answers

1. Photo-editing program: application [1]. Anti-virus utility: system [1]. Operating system: system [1]. Spreadsheet: application [1].

Tip: utility programs serve the computer (keeping it secure or maintained), so they are system software even though the user may start them.

2. Applications are run on the operating system [1]. The operating system is run on the firmware [1]. The bootloader is run on the hardware [1].

Tip: this is the exact layering in syllabus point 4.1.3. “Compiler” and “application” are distractors.

3. A mnemonic is a short code (such as ADD or LDA) that represents a machine code instruction [1]. The translator is an assembler [1].

4. Any three functions, each with a matching use (1 mark for the function, 1 for the description linked to the hospital):

• Managing user accounts [1]: each nurse has their own account, with their own settings and storage area, created and maintained by the OS [1].
• Providing system security [1]: the OS checks each nurse’s username and password before allowing access, so patient data is protected [1].
• Managing files [1]: the OS saves, names, opens and organises the patient records into folders [1].
• Providing an interface [1]: the OS gives the nurses a way to interact with the laptop, such as a graphical user interface with icons and windows [1].
• Managing memory [1]: the OS allocates RAM to the records program while it is open so programs do not overwrite each other’s data [1].
• Managing multitasking [1]: the OS shares processor time so a nurse can keep the records program and email open at once [1].

(Max 6. Do not credit two descriptions of the same function.)

5. (a) Software interrupt [1]. (b) Two processes trying to access the same memory location [1]. (c) Any four from:

• the interrupt signal is sent to the processor [1]
• the processor checks for interrupts and compares the interrupt’s priority with the current task [1]
• the current task’s state (register contents) is saved [1]
• the matching interrupt service routine is run to deal with the error, for example by displaying an error message [1]
• the saved state is restored / the processor continues with the next task, or the program is stopped if the error cannot be recovered [1]

6. (a) Low-level code can directly manipulate the hardware [1], so the programmer can control the motor’s registers or memory locations exactly, which suits an embedded device with a fixed processor [1]. (b) Any two, each explained:

• It is harder to read and write [1], because instructions are mnemonics or binary rather than English-like statements, so the program takes longer to produce [1].
• It is harder to debug [1], so errors in the motor control code take longer to find and correct [1].
• It is not machine independent [1], so if the vacuum cleaner is redesigned with a different processor the program must be rewritten [1].

7. (a) A compiler [1], because it translated the whole program and gave an error report covering all the errors / an executable file is produced only once the code is error-free [1]. (b) An interpreter would translate and execute the code line by line [1]. It would stop when it reached the first error [1] and report only that error; the student would fix it and run again to find the next one [1]. No executable file would be produced.

8. (a)

• Auto-completion: suggests or finishes keywords and identifiers as the programmer types [1].
• Prettyprint: displays the code with colour coding and consistent indentation to make it easier to read [1].
• Run-time environment: allows the program to be run and tested inside the IDE, showing its outputs [1].

(b) Auto-correction automatically fixes some simple mistakes, such as a misspelt keyword, as the code is typed [1]; error diagnostics identify and highlight errors so the programmer can find and fix them, but do not fix them automatically [1].

Where marks are usually lost

• Q4: writing “the OS manages things” — each mark needs a named function and a use tied to the hospital.
• Q5(c): leaving out that the current state is saved and later restored. Without this the answer reads as if the original task is lost.
• Q6: answering “low-level is faster” with no link to hardware control. The syllabus point is direct manipulation of hardware.
• Q7(b): saying an interpreter “finds all the errors one at a time”. It stops at the first error.

Frequently asked questions

How many OS functions should I learn for 0478? All nine listed in learning outcome 4.1.2. Questions usually ask for two to four, often set in a scenario, so practise linking each function to a situation.

Are division by zero and a key press the same kind of interrupt? No. The syllabus classes division by zero as a software interrupt and pressing a key as a hardware interrupt.

Will I be asked to compare a compiler and an interpreter? Yes, it is a common question type. Give each point for both translators, covering how they translate, how errors are reported and whether an executable file is produced.