NCERT Book Class 11 Computer Science Chapter 1 Computer System

Computer System is Chapter 1 of the Class 11 Computer Science NCERT textbook, and it is where the whole subject starts: what a CPU actually does, how memory is layered, and how software sits on top of hardware. The NCERT book Class 11 Computer Science Chapter 1 Computer System file on this page is the official chapter for 2026-27, running to 26 pages with every figure, table, summary point and exercise question in place.

• Chapter: Chapter 1, Computer System, covering sections 1.1 to 1.8
• Book: Computer Science, the Class 11 NCERT textbook for 2026-27, with 11 chapters
• File: 26 pages, the complete official chapter including Summary and Exercise

You can page through the block diagram of a computer system, the microprocessor generation table and the full exercise set in the reader above before downloading the file.

This is the official NCERT chapter file for the 2026-27 session, hosted by Collegedunia with no pages removed.

How the Computer System Chapter Is Laid Out

Chapter 1 moves in a straight line from the physical machine to the software that drives it. The table below lists the eight numbered sections in the order they appear in the file.

What the Computer System Chapter PDF Contains

The PDF holds the chapter exactly as NCERT printed it, from the Alan Turing quotation on the opening page to the last Explore Yourself prompt. Nothing has been trimmed out.

• Figure 1.1, the block diagram showing how the input device, CPU, primary memory, output device and secondary storage connect
• Figure 1.4, the invention timeline from the abacus through Pascaline, the analytical engine and the tabulating machine to the integrated circuit
• Table 1.1, the measurement units from kilobyte to yottabyte, each one 1024 times the last
• Table 1.2, the five generations of microprocessor with era, chip type, word size, clock speed and cores
• Six Activity tasks and three Think and Reflect prompts set in the side margin
• The nine-point Summary, the 14-question Exercise, and eight Explore Yourself investigations

Computer System Class 11 Chapter Revision

Source: Magnet Brains on YouTube

How Data Moves Between the CPU and Memory

Section 1.4 is short but carries two exercise questions. The idea is that components never talk directly; they talk over physical wires called a bus, and there are three of them.

• The data bus carries the actual data, and it is bidirectional because the CPU both reads and writes
• The address bus carries the memory address the CPU wants, and it is unidirectional
• The control bus carries the read or write signal, and it is unidirectional too
• All three together make the system bus shown in Figure 1.8
• On a read, hardware called the memory controller places the data on the data bus

The chapter is equally firm that the CPU cannot reach secondary storage on its own. Anything on a hard disk must be copied into main memory first, which is why Figure 1.1 runs input device, then primary memory, then CPU, then back out.

How Chapter 1 Splits System Software from Application Software

Section 1.7 is the longest stretch of the chapter and is almost entirely classification, so a table is the fastest way to hold it. Figure 1.13 draws the same split as a tree.

Section 1.8 then treats the operating system on its own as a resource manager, with process, memory, file and device management as its four functions, and command based, graphical, touch, voice and gesture as its five interface types.

What the Computer System Exercises Ask

The 14 exercise questions are spread across the whole chapter rather than clustered at the end, so skipping a section usually costs a question. Several ask for a comparison rather than a definition.

A Reading Plan for the Computer System Chapter

Twenty-six pages of theory can feel flat read straight through. Work in passes instead, and use the figures as the skeleton rather than the prose.

• Start with Figure 1.1 and redraw it from memory. Six boxes and the arrows between them cover most of section 1.1
• Learn the memory ladder in order of speed: registers, cache, RAM, then secondary storage, getting slower and cheaper as you go down
• Fix the two pairs examiners like: RAM against ROM on volatility, and microprocessor against microcontroller on what is embedded in the chip
• Finish with the three data types, then attempt exercise question 12, which is exactly that classification

What Collegedunia Adds to the Computer System Chapter PDF

Collegedunia gives you the official file plus a way into it. The chapter PDF itself is untouched NCERT material.

• Official file: the exact NCERT chapter PDF, with no pages removed
• Read in the browser: page through all 26 pages before you download
• Chapter list: jump to any other chapter of the book from one table
• Study material: notes, solutions and handwritten notes for the same chapter

Also Check: the other Class 11 Computer Science resources for Computer System and for the chapter after it.

Class 11 Computer Science NCERT Book PDF: All Chapters

Every chapter of the Class 11 Computer Science book sits on its own page. The book has 11 chapters, opening with three theory chapters before Python begins in Chapter 5.

Computer System Class 11 Computer Science NCERT Book PDF FAQs