Computer ScienceCBSE Class 11 · Computer System

Software, Translators and the Operating System Class 11 Computer Science

Updated 17 October 2026 · Fact-checked

System software (operating system, utilities, device drivers, language translators) manages the computer; application software does a user task. A translator converts a program into machine language: an assembler for assembly language, a compiler for the whole high-level program, an interpreter line by line. The operating system manages processes, memory, files and devices and gives a user interface.

Understand Software, Programming Languages, Translators and the Operating System

Software classification. *System software*: operating system, system utilities, device drivers, language translators. *Programming tools*: editors, debuggers, IDEs, linkers. *Application software*: general (word processor, spreadsheet, browser) and specific (payroll, railway reservation).

Languages. *Machine language* (binary, directly understood by the CPU); *assembly language* (mnemonics such as ADD, translated by an assembler); *high-level languages* (Python, C++, Java; closer to English, machine independent).

Translators.

	Compiler	Interpreter
Input	Whole program	One statement at a time
Output	Object code, saved	Executes immediately, no object file
Errors	Reported for the whole program after compiling	Stops at the first error
Speed of running	Faster after compilation	Slower, translates each time
Example	C, C++	Python (commonly interpreted)

An *assembler* converts assembly language to machine code.

Operating system. It acts as an interface between the user and the hardware and manages resources. Functions: *process management* (scheduling the CPU), *memory management*, *file management*, *device management*, *security* and the *user interface* (command line (CLI) or graphical (GUI)). Examples: Windows, Linux, macOS, Android.

Licences. Proprietary software is bought and cannot be freely modified; freeware is free to use but source not available; open source software has source code available and may be modified under its licence.

Utilities. Disk cleaner, antivirus, backup, file compression. Device drivers let the OS talk to a hardware device such as a printer.

Software, Programming Languages, Translators and the Operating System: key facts

Software types: System software OS, utilities, drivers, translators
Application software general and specific
Programming tools editor, debugger, IDE; Three groups.
Translators: Assembler assembly to machine code
Compiler whole program at once
Interpreter line by line; Machine language is the target.
OS functions: Process management
Memory management
File management
Device management
Security
User interface; Interface between user and hardware.
Compiler versus interpreter: Compiler: object code kept, fast to run | Interpreter: no object code, stops at first error; Python is usually interpreted.

System software	OS, utilities, drivers, translators
Application software	general and specific
Programming tools	editor, debugger, IDE

Assembler	assembly to machine code
Compiler	whole program at once
Interpreter	line by line

How to answer Software, Programming Languages, Translators and the Operating System questions

Theory questions in this chapter are scored on correct classification and clear contrasts.

1Decide whether the item manages the computer (system) or does a user task (application).
2For translators, ask: what is the input and does it translate the whole program or one line?
3For OS functions, link each function to the resource it manages.
4In contrasts, give a pair of points for each side, one row per point.
5Add one example for each term.

Software, Programming Languages, Translators and the Operating System in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

A print job

Suppose a clerk presses Print in a word processor and a new printer starts working only after its driver is installed.

Which kinds of software are involved?

Try it first, then show the solutionSolution

The word processor is application software.
The driver is system software that lets the OS communicate with the printer; the OS manages the device.

Answer: Word processor: application; driver and OS: system software.

Memory hook: App asks, OS manages, driver talks to the device.

Tricks to remember Software, Programming Languages, Translators and the Operating System

Short memory aids. Say each one aloud once, then use it on a question the same day.

A-C-I
Assembler for assembly, Compiler for whole program, Interpreter for each line.
Use it when: Translators.
PMFD
Process, Memory, File, Device management.
Use it when: OS functions.

Software, Programming Languages, Translators and the Operating System: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Translator · 1 mark · MCQBoard level

Which translator converts assembly language into machine language?
(a) Compiler
(b) Interpreter
(c) Assembler
(d) Linker

Try it first, then show the solutionSolution

The assembler handles assembly language.

Answer: (c) Assembler

Example 2: Classify · 4 marks · Short answerBoard level

Classify as system software or application software: (i) Linux; (ii) a spreadsheet; (iii) a printer driver; (iv) a payroll program. (4 marks)

Try it first, then show the solutionSolution

(i) System software (operating system).
(ii) Application software.
(iii) System software (device driver).
(iv) Application software (specific).

Answer: (i) System (ii) Application (iii) System (iv) Application

Example 3: Compiler versus interpreter · 4 marks · Short answerHarder board level

Distinguish between a compiler and an interpreter on four points. (4 marks)

Try it first, then show the solutionSolution

Input: compiler translates the whole program; interpreter translates one statement at a time.
Object code: compiler produces and saves it; interpreter does not.
Errors: compiler lists errors after compiling the whole program; interpreter stops at the first error.
Speed: compiled code runs faster; an interpreted program is slower because every line is translated each time.

Answer: Whole versus line by line; object code; error reporting; speed.

Example 4: OS functions · 3 marks · Short answerHarder board level

Explain any three functions of an operating system with one example each. (3 marks)

Try it first, then show the solutionSolution

Process management: decides which program the CPU runs next, such as switching between a music player and a browser.
Memory management: allots RAM to programs and frees it after they stop.
File management: creates, names, stores and protects files and folders.

Answer: Process, memory and file management with an example each.

Example 5: Choose the translator · 4 marks · Short answerHOTS / competency

A student writes a Python script and notices that a syntax error in line 40 does not prevent lines 1 to 39 from executing before the error message appears. Explain with reference to the translator why this happens and what would be different with a compiled language. (4 marks)

Try it first, then show the solutionSolution

Python is usually run by an interpreter, which translates and executes line by line.
Lines 1 to 39 are executed before the interpreter reaches line 40 and reports the error.
A compiler translates the whole program first, so it would report the error before any line runs and produce no executable until the error is fixed.

Answer: Line-by-line interpretation executes earlier lines first; a compiler would stop before running.

Where students lose marks in Software, Programming Languages, Translators and the Operating System

The slips examiners see most often, and what to write instead.

Mistake: Calling a compiler an interpreter
Mixing up line by line and whole program.
Wrong working
Compiler translates one line at a time.
Right working
Compiler translates the whole program; interpreter one line at a time.
Do this: Remember: compile means whole.
Usually costs: 1 mark
Mistake: Listing an editor as system software
Missing programming tools.
Wrong working
Text editor is system software.
Right working
Text editor is a programming tool or application.
Do this: Know the three groups.
Usually costs: 1 mark
Mistake: No example
Writing only definitions.
Wrong working
OS manages memory.
Right working
OS manages memory, for example allotting RAM to each open program.
Do this: Add a one-line example.
Usually costs: 1/2 mark

Exam tips

Use a table for compiler versus interpreter.
Give an example for every software type.
Mention "interface between user and hardware" for OS.
Write full forms: CLI, GUI, IDE.

Practice questions on Software, Programming Languages, Translators and the Operating System

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
An operating system is:
(a) application software
(b) system software
(c) a programming language
(d) a compiler
Hint
It manages resources.
Answer
(b) system software
Q2 · 3 marks · Short answerHarder board level
Differentiate between a CLI and a GUI with one advantage of each. (3 marks)
Hint
Typed commands versus icons.
Answer
A CLI accepts typed commands (fast for experts and uses little memory); a GUI uses windows, icons and a pointer (easier for beginners). Example CLI: command prompt; example GUI: Windows desktop.
Q3 · 3 marks · Short answerHarder board level
What is a device driver and why is it needed when a new scanner is connected? (3 marks)
Hint
Hardware talks through software.
Answer
A device driver is system software that lets the operating system communicate with a hardware device. Without it the OS does not know how to send commands to the scanner or read its data.
Q4 · 1 mark · Assertion-reasonHarder board level
Assertion (A): Python programs cannot be run without compiling them first.
Reason (R): Python is usually executed by an interpreter.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Hint
Python is usually interpreted.
Answer
(d) A is false, but R is true.
Q5 · 4 marks · Short answerHOTS / competency
A company has bought a licensed office package for staff, uses a free PDF reader whose source code it cannot see, and runs a web server built on open source software. Classify each licence type and say which of the three the company is allowed to modify, with a condition. (4 marks)
Hint
Source availability.
Answer
The office package is proprietary; the PDF reader is freeware; the web server is open source. Only the open source software can be modified, subject to the terms of its licence.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Which software manages hardware?Show answer
System software, mainly the operating system.
2.What does an assembler translate?Show answer
Assembly language to machine code.
3.Which translator stops at the first error?Show answer
Interpreter.
4.Name two OS functions.Show answer
Process management and memory management.
5.What is a device driver?Show answer
Software that lets the OS control a device.

Software, Programming Languages, Translators and the Operating System: frequently asked questions

Is Python compiled or interpreted?

It is usually run by an interpreter.

What is an IDE?

A tool that combines an editor, translator and debugger.

Is freeware the same as open source?

No; freeware is free to use but need not provide source code.