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Unit 2 of 4 · B.Sc IT Sem 1

Unit 2: Memory, I/O and languages

Information Technology notes · PTU syllabus (BSIT104/BSBC104)

3 min read6 topics10 exam questions
On this page
  1. Unit summary
  2. Memory types
  3. Input and output units
  4. Storage devices
  5. Printer types
  6. Programming languages and translators
  7. System and application software
  8. Key terms
  9. Quick revision
  10. Important questions

Unit summary

Memory stores data and programs, devices move information in and out, and languages let people instruct computers. This unit covers memory types — magnetic core, RAM, ROM, secondary and cache — input/output units, storage devices, printer types, machine, assembly, high-level and fourth-generation languages, compilers, interpreters and assemblers, and system and application software.

After this unit you can

  • Explain types of memory
  • Explain input, output and storage devices and printers
  • Distinguish generations of programming languages and translators
  • Distinguish system and application software

PTU syllabus topics

  • Memory types (magnetic core, RAM, ROM, secondary, cache)
  • input/output units
  • storage devices
  • printer types
  • machine/assembly/high-level/4GL languages
  • compilers
  • interpreters
  • assemblers
  • system and application software
HierarchyMemory hierarchy
  1. Registers

    Fastest, smallest, inside the CPU

  2. Cache

    Very fast, small

  3. Main memory (RAM)

    Fast, volatile

  4. Secondary storage

    SSD, HDD: large, slower

  5. Archival storage

    Tape, cloud: largest, slowest

1

Topic 1

Memory types

ComparisonPrimary vs secondary memory
Primary memory
Secondary memory

Examples

RAM, ROM, cache

Hard disk, SSD, pen drive, DVD

Volatility

RAM volatile; ROM non-volatile

Non-volatile

Speed

Fast

Slower

Capacity and cost

Small, costly per GB

Large, cheap per GB

Storage units: 8 bits = 1 byte; 1 KB = 1024 bytes; MB, GB, TB follow in steps of 1024.

  • Magnetic core memory: early primary memory (1950s–1970s) using tiny magnetised rings — non-volatile but replaced by semiconductor RAM.
  • Cache memory: small, very fast memory between CPU and RAM holding frequently used data — levels L1, L2, L3.
HierarchyMemory hierarchy
  1. Registers

    Fastest, smallest

  2. Cache

    L1, L2, L3

  3. Main memory (RAM)
  4. Secondary storage

    SSD, HDD

  5. Tertiary and offline storage

    Tape, optical, cloud backup

2

Topic 2

Input and output units

ComparisonInput vs output devices
Input devices
Output devices

Function

Send data into the computer

Present results from the computer

Examples

Keyboard, mouse, scanner, microphone, webcam, touch screen, barcode and QR readers, OMR, MICR

Monitor, printer, speakers, projector, plotter

3

Topic 3

Storage devices

  • Magnetic: hard disk drives, magnetic tape; optical: CD, DVD, Blu-ray; solid-state: SSD, USB pen drives, memory cards; cloud storage: Google Drive, OneDrive.
  • Comparison factors: capacity, speed, cost per GB, durability, portability.
4

Topic 4

Printer types

ClassificationPrinters
Printers

  • Impact

    Dot matrix (multi-part forms), line printers

  • Non-impact

    Inkjet (home, photos), laser (offices, fast, sharp text), thermal (receipts, labels)

  • Specialised

    Plotters (engineering drawings), 3D printers

5

Topic 5

Programming languages and translators

ComparisonCompiler vs interpreter
Compiler
Interpreter

Translation

Whole program at once

Line by line

Speed of execution

Faster

Slower

Errors

Reported after compiling the whole program

Reported line by line

Examples

C, C++

Python, JavaScript

Assemblers translate assembly language into machine code.

GenerationLanguage
1GLMachine language (binary)
2GLAssembly language (mnemonics)
3GLHigh-level languages (C, Java, Python)
4GLQuery and report languages (SQL)
5GLAI and logic languages (Prolog)
  • Fourth-generation languages (4GL): closer to human language, specify what is needed rather than how — SQL, report generators, MATLAB.
6

Topic 6

System and application software

ComparisonSystem vs application software
System software
Application software

Purpose

Runs and manages the computer

Performs specific user tasks

Examples

Windows, Linux, device drivers, utilities

MS Word, Tally, browsers

User interaction

Indirect

Direct

Dependence

Runs independently

Needs system software to run

Key terms

RAM
Volatile read-write main memory
Cache
High-speed memory between CPU and RAM
SSD
Solid-state drive using flash memory
Assembler
Translates assembly language into machine code
4GL
Fourth-generation, non-procedural language

Quick revision

  • Magnetic core, RAM (SRAM, DRAM), ROM (PROM, EPROM, EEPROM), cache, secondary; memory hierarchy.
  • Input and output devices.
  • Magnetic, optical, solid-state, cloud storage.
  • Impact and non-impact printers.
  • Machine, assembly, high-level, 4GL; compiler, interpreter, assembler; system vs application software.

Important exam questions

Practice questions written to the PTU exam pattern for this unit's syllabus: short answers (Section A style) and long answers (Sections B and C style).

Short-answer questions

  1. Q1.Distinguish RAM and ROM.
  2. Q2.What is cache memory?
  3. Q3.Name four input devices.
  4. Q4.Distinguish impact and non-impact printers.
  5. Q5.Distinguish a compiler and an interpreter.
  6. Q6.Give two examples each of system and application software.

Long-answer questions

  1. Q1.Explain the types of memory and the memory hierarchy.
  2. Q2.Explain input, output and storage devices.
  3. Q3.Explain generations of programming languages and language translators.
  4. Q4.Distinguish system software and application software with examples.

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