Computer Hardware Questions for SBI PO

What is Computer Hardware

Hardware refers to all the physical, tangible parts of a computer that you can touch and see. Think of hardware as the body of a computer and software as its mind. Hardware includes everything from the keyboard you type on to the chips inside the motherboard. The five classic functions of hardware are Input, Processing, Output, Storage, and Communication.

• Hardware = physical components of a computer system
• Five functions: Input, Process, Output, Store, Communicate
• Hardware without software is like a car without a driver
• Classified broadly as: Input Devices, Output Devices, Processing Devices, Storage Devices
• All hardware communicates through the motherboard acting as a central hub

Input Devices

Input devices allow the user to feed data or instructions into the computer. The computer cannot process anything unless it first receives input. Remember the mnemonic KMSST for the most common ones. Input devices only send data into the system and cannot display or store results on their own.

• Keyboard: most common input device, sends text and commands
• Mouse: pointing device, sends positional and click data
• Scanner: converts physical documents into digital images
• Microphone: converts sound into digital input
• Barcode Reader and OMR (Optical Mark Reader): used in exams and retail
• Joystick and Light Pen: specialty input devices often asked in MCQs
• Webcam: captures video/image input

Output Devices

Output devices present the processed result to the user. They only receive data from the computer and convert it into human-readable form. The key rule: if it shows, prints, or plays the result, it is an output device. Monitor, Printer, and Speaker are the classic trio every examiner loves to test.

• Monitor (VDU - Visual Display Unit): displays text and graphics
• Printer: produces hard copy output. Types are Inkjet, Laser, Dot Matrix
• Speaker: audio output device
• Plotter: draws large-scale graphics, used in engineering drawings
• Projector: displays output on a large screen
• Dot Matrix is an impact printer; Inkjet and Laser are non-impact printers

Processing Device - CPU

The CPU (Central Processing Unit) is the brain of the computer. It has three main parts: ALU (Arithmetic Logic Unit) for calculations, CU (Control Unit) for directing traffic between components, and Registers for temporary high-speed storage. The CPU speed is measured in GHz (Gigahertz). SBI PO often asks about CPU components and what each part does.

• ALU performs arithmetic (+,-,*,/) and logical (AND, OR, NOT) operations
• Control Unit directs all other hardware components
• Registers are the fastest and smallest memory inside the CPU
• Clock Speed measured in GHz - higher means faster processing
• Cache Memory is a small fast memory between CPU and RAM
• Multi-core processors (Dual, Quad, Octa) run multiple tasks simultaneously

Memory - Primary and Secondary

Memory is where data lives. Primary memory is directly accessible by the CPU and is fast but temporary (volatile). Secondary memory is permanent (non-volatile) and much larger but slower. Think of Primary Memory as your office desk (fast, limited space) and Secondary Memory as your filing cabinet (slow, large space).

• RAM (Random Access Memory): volatile, temporary, working memory of a computer
• ROM (Read Only Memory): non-volatile, stores BIOS/firmware, cannot be easily changed
• Cache Memory: fastest memory, sits between CPU and RAM
• Hard Disk Drive (HDD): magnetic secondary storage, large capacity
• SSD (Solid State Drive): faster than HDD, no moving parts, uses flash memory
• USB Flash Drive, CD, DVD, Blu-ray: portable secondary storage devices
• RAM is measured in GB today; storage in GB or TB

Storage Capacity and Data Units

Data is measured in bits and bytes. This is a favourite calculation area in SBI PO. A bit is the smallest unit (0 or 1). Eight bits make one byte. From there the units scale up by a factor of 1024. Remembering the order with a mnemonic saves time in the exam.

• 1 Bit = smallest unit (0 or 1)
• 1 Byte = 8 Bits
• 1 Kilobyte (KB) = 1024 Bytes
• 1 Megabyte (MB) = 1024 KB
• 1 Gigabyte (GB) = 1024 MB
• 1 Terabyte (TB) = 1024 GB
• 1 Petabyte (PB) = 1024 TB

Motherboard and Ports

The motherboard is the main circuit board that connects all hardware components. It is like the road network of a city connecting everything. Ports are physical connectors on the outside of the computer for attaching devices. SBI PO asks which port is used for which device.

• USB (Universal Serial Bus): most common port for pen drives, keyboards, mice
• HDMI: for connecting monitors and projectors (audio + video combined)
• VGA: older monitor connection port (video only)
• Ethernet (RJ-45): for wired internet connection
• PS/2 Port: older port for keyboard and mouse (round connector)
• Audio Jack (3.5mm): for speakers and headphones
• SATA: internal port connecting HDD and SSD to motherboard

Devices that are Both Input and Output

Some devices can both send and receive data. These dual-purpose devices are a favourite trick question in SBI PO. The classic example is a Touch Screen which takes touch as input and displays output. A Modem sends and receives internet signals. A Network Interface Card (NIC) both sends and receives network data.

• Touch Screen: input (touch) + output (display)
• Modem: sends and receives data over telephone lines
• Network Interface Card (NIC): sends and receives network packets
• Headset with microphone: mic is input, earphone is output
• CD-RW and DVD-RW: read (output) and write (input) data

• Confusing RAM and ROM: RAM is temporary and used for running programs; ROM is permanent and stores startup instructions. Never swap these in answers.
• Treating Hard Disk as Primary Memory: HDD and SSD are secondary storage. Only RAM and ROM are primary memory. A very common MCQ trap.
• Using 1000 instead of 1024 for data unit conversions: In binary units, 1 KB = 1024 Bytes, not 1000. Exams occasionally use 1000 in SI context but default to 1024 for computer questions.
• Classifying Modem or Touch Screen as only Input or only Output: These are both Input and Output devices. Marking them as only one type will cost you marks.
• Confusing Plotter with Printer: Both produce hard copy but Plotter is specifically for large engineering or architectural drawings. Printer is for general documents.

• IPOS Framework: Input - Process - Output - Storage. Every hardware device fits one of these four. Classify first, answer second.
• For data units remember: Killer Monkeys Grab Tigers Painfully = KB, MB, GB, TB, PB. Each step is 1024 times bigger.
• CPU = ACR: ALU (calculates), CU (controls), Registers (remembers temporarily). Think ACR like an Air Conditioner Remote - it calculates settings, controls the machine, and remembers your preferences.
• RAM is like your study table (active, quick access, limited), Hard Disk is like your bookshelf (large, slower, permanent). This analogy instantly answers primary vs secondary memory questions.

• SBI PO Computer section typically has 20 questions in Prelims combined with other sections. Hardware contributes 3-5 direct questions. These are the easiest to score so never skip this topic.
• Input vs Output vs Both classification is a repeated question type. Prepare a quick mental table of at least 15 devices and their type before the exam.
• Data unit conversion questions appear in a tricky format like: A file is 2 MB. How many KB is it? Answer = 2048 KB. Practice 5 such conversions to build speed.
• Port identification questions show up occasionally with images or descriptions. Focus on USB, HDMI, VGA, Ethernet, and PS/2 as these are most frequently tested.
• Questions sometimes describe a function and ask you to name the hardware. For example: which device converts digital signals to analog for phone line transmission? Answer: Modem. Practice function-to-device mapping rather than device-to-function only.