Computer Knowledge

1. Computer Fundamentals: Hardware, Software, Memory and Number Systems

Computer Knowledge questions are mostly direct facts. This lesson covers the basics that appear in almost every paper: generations, parts of a computer, input and output devices, memory units and number systems.

History and generations

• Charles Babbage is called the 'Father of the Computer'. He designed the Analytical Engine in the 1830s.
• ENIAC (1945) was an early general-purpose electronic digital computer. UNIVAC I (1951) was an early commercial computer.
• First generation (about 1940-1956): vacuum tubes. Second generation (about 1956-1963): transistors.
• Third generation (about 1964-1971): integrated circuits (ICs). Fourth generation (1971 onwards): microprocessors.
• Fifth generation: based on artificial intelligence (AI) and parallel processing; still developing.

Hardware, software and the CPU

• Hardware is the physical parts you can touch. Software is the set of programs that tells the hardware what to do.
• System software runs the computer (operating system, device drivers, utilities). Application software does user tasks (MS Word, browsers, Tally).
• The CPU (Central Processing Unit) is the 'brain' of the computer. It has the ALU (Arithmetic Logic Unit), the CU (Control Unit) and registers.
• Input devices: keyboard, mouse, scanner, microphone, webcam, barcode reader, OMR, MICR (used for cheques), light pen, joystick.
• Output devices: monitor, printer, speaker, projector, plotter. A touch screen is both input and output.
• A compiler translates the whole program at once; an interpreter translates line by line; an assembler converts assembly language to machine code.

Memory and storage

• Primary memory: RAM is volatile (data is lost when power goes off); ROM is non-volatile (keeps data, e.g. the start-up firmware).
• Cache memory is a small, very fast memory between the CPU and RAM. Registers inside the CPU are the fastest of all.
• Secondary storage keeps data permanently: hard disk (HDD, magnetic), SSD and pen drive (flash memory), CD/DVD/Blu-ray (optical).
• Units: 1 bit = 0 or 1; 4 bits = 1 nibble; 8 bits = 1 byte.
• 1 KB = 1024 bytes; 1 MB = 1024 KB; 1 GB = 1024 MB; 1 TB = 1024 GB; 1 PB = 1024 TB (the convention used in exams).

Number systems basics

• Binary is base 2 (digits 0, 1). Octal is base 8 (0-7). Decimal is base 10 (0-9). Hexadecimal is base 16 (0-9 and A-F, where A = 10 and F = 15).
• Binary to decimal: multiply each digit by its place value (1, 2, 4, 8, 16 ... from the right). Example: 1101 = 8 + 4 + 0 + 1 = 13.
• Decimal to binary: divide by 2 again and again and read the remainders from bottom to top. Example: 10 = 1010.
• Computers work in binary because electronic circuits have two states: on (1) and off (0).

💡 Memorise the memory ladder in order: bit, nibble, byte, KB, MB, GB, TB, PB. Each step after byte is x 1024 in exam questions.

📝 5-question quiz on this lesson: enrol free to take it and track your score.

2. Operating Systems, Windows, File Management and Shortcuts

The operating system (OS) is the most important system software. It starts the computer and manages hardware, files and programs. Exams ask about OS basics, Windows features and keyboard shortcuts.

Operating system basics

• An OS manages memory, the processor, devices and files, and gives a user interface.
• Examples: Windows and macOS (desktop), Linux (open source), Android and iOS (mobile).
• GUI (Graphical User Interface) uses icons, windows and a mouse. CLI (Command Line Interface) uses typed commands, as in MS-DOS.
• Booting means starting the computer. A cold boot starts from power off; a warm boot is a restart.
• The BIOS or UEFI firmware runs first when the computer starts and then loads the OS.

Windows and file management

• The desktop is the main screen. The taskbar shows open programs; the Start button opens the Start menu.
• File Explorer is used to open, copy, move, rename and delete files and folders.
• A folder holds files and other folders. A file name has an extension that shows its type: .txt, .exe, .jpg, .pdf, .mp3, .zip.
• Deleted files go to the Recycle Bin and can be restored. Shift + Delete removes them without using the Recycle Bin.
• Files deleted from a pen drive or network drive usually do not go to the Recycle Bin.

Windows keyboard shortcuts

• Ctrl + C copy, Ctrl + X cut, Ctrl + V paste, Ctrl + Z undo, Ctrl + Y redo, Ctrl + A select all.
• Alt + Tab switches between open apps. Alt + F4 closes the active app.
• Windows key + D shows the desktop; Windows key + E opens File Explorer; Windows key + L locks the PC.
• Windows key + R opens Run; Windows key + I opens Settings; Ctrl + Shift + Esc opens Task Manager.
• F2 renames the selected file; F5 refreshes; Ctrl + Shift + N creates a new folder in File Explorer.
• Windows key + Shift + S takes a screenshot of part of the screen; Windows key + V opens clipboard history (it must first be turned on in Settings).

💡 Practise each shortcut on a real computer a few times. Shortcuts you have used are much easier to recall in the exam than ones you only read.

📝 5-question quiz on this lesson: enrol free to take it and track your score.

3. MS Word, Excel and PowerPoint

Microsoft Office is used in almost every government office. Exams ask about features, Excel functions, file extensions and shortcuts in Word, Excel and PowerPoint.

MS Word

• Word is a word processor. Its default file extension is .docx (Word 2007 onwards); the old format is .doc. Templates use .dotx.
• Ctrl + B bold, Ctrl + I italic, Ctrl + U underline. Ctrl + E centre, Ctrl + L left, Ctrl + R right, Ctrl + J justify.
• Ctrl + F find (opens the Navigation pane), Ctrl + H replace, Ctrl + K insert hyperlink, Ctrl + Enter page break, F7 spelling and grammar check, F12 Save As.
• Mail Merge creates many personalised letters or labels from one document and a list of names and addresses.
• Header and footer appear at the top and bottom of every page. Track Changes records edits made by reviewers.

MS Excel

• Excel is a spreadsheet. A workbook (.xlsx) contains worksheets made of cells. A cell address is column letter + row number, e.g. B3.
• Every formula starts with =. SUM adds, AVERAGE gives the mean, MAX and MIN give the largest and smallest, COUNT counts cells with numbers.
• IF tests a condition: =IF(B2>=35,"Pass","Fail").
• VLOOKUP looks up a value in the first column of a table and returns a value from another column: =VLOOKUP(value, table, column number, FALSE) for an exact match.
• XLOOKUP is a newer, more flexible lookup function, available in Microsoft 365 and Excel 2021 onwards. It can look left or right and gives an exact match by default.
• $A$1 is an absolute reference (does not change when copied); A1 is relative. F4 switches between the reference types.

Excel shortcuts and errors; PowerPoint

• Excel: Alt + = AutoSum; Ctrl + ; inserts today's date; Ctrl + Shift + : inserts the current time; F2 edits the active cell; Ctrl + 1 opens Format Cells.
• Excel errors: #DIV/0! (division by zero), #N/A (value not found), #NAME? (wrong function name), #REF! (invalid cell reference), ##### (column too narrow).
• PowerPoint is for presentations; its default extension is .pptx. Ctrl + M adds a new slide.
• F5 starts the slide show from the first slide; Shift + F5 starts from the current slide; Esc ends the show.
• A transition is the effect between two slides; an animation is the effect on an object (text or picture) within a slide.
• Slide Sorter view shows small versions of all slides so you can rearrange them.

💡 For Excel functions, remember the argument order: VLOOKUP(what to find, where to look, which column, FALSE). Exams often change one argument in the options.

📝 5-question quiz on this lesson: enrol free to take it and track your score.

4. Internet, Networking, Cyber Security and Karnataka e-Governance

This lesson covers how networks and the internet work, how to stay safe online, and the e-governance services of Karnataka. Full forms of computer terms are also asked often.

Networks and the internet

• LAN (Local Area Network): one building or campus. MAN (Metropolitan Area Network): a city. WAN (Wide Area Network): countries; the internet is the largest WAN.
• Router connects different networks; switch connects devices within a LAN; modem (modulator-demodulator) converts signals for the phone or cable line.
• An IP address identifies a device on a network. IPv4 uses 32 bits; IPv6 uses 128 bits. DNS converts domain names (like karnataka.gov.in) into IP addresses.
• A URL (Uniform Resource Locator) is a web address. HTTP is the protocol for web pages; HTTPS is HTTP with encryption (a padlock in the browser).
• Wi-Fi is wireless networking based on the IEEE 802.11 standards. Bluetooth is for short-range connections between nearby devices.
• Web browsers: Chrome, Firefox, Edge, Safari. A search engine (Google, Bing) finds web pages.

Email and protocols

• SMTP is used to send email; POP3 and IMAP are used to receive email. FTP transfers files.
• In an email, CC (carbon copy) recipients are visible to all; BCC (blind carbon copy) recipients are hidden from the others.
• An attachment is a file sent with an email. Spam is unwanted bulk email.
• An email address has a user name and a domain separated by @, e.g. [email protected].

Cyber security basics

• Phishing: fake emails or websites that steal passwords or bank details. Vishing is by phone call; smishing is by SMS.
• Malware is harmful software: a virus attaches to files; a worm spreads by itself over networks; a Trojan pretends to be useful; ransomware locks files and demands money; spyware secretly collects information.
• Use strong passwords (long, with letters, numbers and symbols), a different password for each account, and two-factor authentication (2FA).
• Never share OTP, PIN or CVV with anyone, even if the caller says he is from a bank or the police.
• Report cyber fraud quickly: call the national helpline 1930 or file a complaint at cybercrime.gov.in.
• A firewall blocks unauthorised network traffic; antivirus software finds and removes malware.

Karnataka e-governance and common full forms

• Bhoomi: Karnataka's computerised land records system of the Revenue Department. It gives the RTC (Record of Rights, Tenancy and Crops), also called Pahani.
• Kaveri (now Kaveri 2.0): online property registration of the Department of Stamps and Registration; also gives encumbrance certificates (EC).
• Seva Sindhu: the state's single online portal for applying for many government services and schemes.
• Sakala: guarantees time-bound delivery of public services under the Karnataka Sakala Services Act, 2011. e-Swathu: property records of rural (gram panchayat) areas.
• Full forms: CPU Central Processing Unit; RAM Random Access Memory; ROM Read Only Memory; USB Universal Serial Bus; BIOS Basic Input/Output System.
• Full forms: HTML HyperText Markup Language; HTTP HyperText Transfer Protocol; WWW World Wide Web; PDF Portable Document Format; OCR Optical Character Recognition; UPI Unified Payments Interface.

💡 Make a two-column list of 40 full forms and revise it daily in the last week. Full-form questions are the fastest marks in Computer Knowledge.

📝 5-question quiz on this lesson: enrol free to take it and track your score.