RRB ALP IT & Electronic System Maintenance Trade — Complete CBT-2 Study Guide

• Core components: CPU (Central Processing Unit — executes instructions, the "brain" of the computer), RAM (Random Access Memory — fast, volatile working memory that loses its contents when power is removed), Storage (HDD — mechanical, slower, cheaper per GB; SSD — solid-state, much faster, no moving parts, now standard in most new systems). • Motherboard connects and allows communication between all major components (CPU, RAM, storage, expansion cards) via its chipset and various buses/slots. • Power Supply Unit (PSU) converts AC mains power to the various DC voltages (commonly +12V, +5V, +3.3V) required by internal components — must be rated with sufficient wattage for the system's total power draw. • BIOS/UEFI is firmware stored on the motherboard that initializes hardware and starts the boot process before the operating system loads — UEFI (modern replacement for legacy BIOS) supports larger drives, faster boot, and a graphical interface.

• A LAN (Local Area Network) connects devices within a limited area (office, building); a WAN (Wide Area Network) spans larger geographic distances, connecting multiple LANs (the Internet is the largest WAN). • Networking devices: Switch (connects devices within a LAN, forwards data only to the intended destination port based on MAC address), Router (connects different networks together, forwards data based on IP address, e.g. connecting a LAN to the Internet). • IP address uniquely identifies a device on a network; a Subnet mask determines which portion of an IP address identifies the network versus the specific host device. • Wi-Fi (wireless LAN, IEEE 802.11 standards) allows devices to connect to a network without physical cables — security protocols like WPA2/WPA3 encrypt wireless traffic to prevent unauthorized access.

• An OS manages hardware resources and provides a platform for application software to run — core functions include process management, memory management, file system management, and device (driver) management. • Common desktop OS families: Windows (widely used, proprietary), Linux (open-source, highly customizable, common in servers), macOS (Apple's proprietary OS for its own hardware). • File systems (e.g. NTFS for Windows, ext4 for Linux) organize how data is stored and retrieved on a storage device — different file systems have different maximum file/partition size limits and feature sets (permissions, journaling for crash recovery, etc.). • Device drivers are software that allow the OS to communicate with specific hardware components — an incorrect or missing driver can cause a device to malfunction or be entirely unrecognized by the system.

• Input devices (keyboard, mouse, scanner) send data/commands INTO the computer; Output devices (monitor, printer, speakers) send data/results OUT from the computer for the user to perceive. • Printer types: Inkjet (sprays liquid ink droplets, good for photo-quality color at lower volume), Laser (uses toner powder fused by heat, faster and more cost-effective for high-volume text printing), Dot-matrix (impact printing via pins striking an ink ribbon, largely legacy but still used for multi-part carbon-copy forms). • Common peripheral connection interfaces: USB (Universal Serial Bus — the most common general-purpose interface for a wide range of devices), HDMI (carries digital video AND audio to a display), and legacy interfaces like VGA/serial ports still found on some industrial/older equipment. • Basic peripheral troubleshooting: check physical cable/connection first, then check if the device is recognized by the OS (device manager), then check/reinstall the appropriate driver — this order resolves the large majority of common peripheral faults.