Complete list of file extensions (.docx, .pdf, .jpg, .mp3), important computer abbreviations and full forms frequently asked in UPSSSC AGTA and government exams.
Mind Map: File Extensions & Abbreviations
What are File Extensions?
A file extension is the suffix at the end of a filename (after the dot) that indicates the file type and which program should open it. For example, in report.docx, the extension is .docx which tells the computer it's a Microsoft Word document.
Extensions act like file-type signals, helping the operating system choose the correct application for opening each file.
Common File Extensions by Category
Document Files
Extension
Software
Description
.docx
MS Word
Word document
.doc
MS Word (old)
Word 97-2003 document
.pdf
Adobe Reader
Portable Document Format — universal, non-editable
This lesson works best as a reference chapter, but the abbreviations become easier to remember when grouped by idea. Instead of memorizing one long mixed list, connect each short form to the topic where you already studied the concept: hardware terms with CPU and memory, internet terms with networking, and finance terms with digital payments.
Grouping abbreviations by topic makes revision easier than memorizing a long mixed list.
Hardware
Abbreviation
Full Form
CPU
Central Processing Unit
ALU
Arithmetic Logic Unit
CU
Control Unit
RAM
Random Access Memory
ROM
Read Only Memory
HDD
Hard Disk Drive
SSD
Solid State Drive
USB
Universal Serial Bus
HDMI
High Definition Multimedia Interface
VGA
Video Graphics Array
BIOS
Basic Input Output System
SMPS
Switched Mode Power Supply
LED
Light Emitting Diode
LCD
Liquid Crystal Display
Software & OS
Abbreviation
Full Form
OS
Operating System
GUI
Graphical User Interface
CLI
Command Line Interface
DBMS
Database Management System
SQL
Structured Query Language
API
Application Programming Interface
ERP
Enterprise Resource Planning
Networking & Internet
Abbreviation
Full Form
LAN
Local Area Network
PAN
Personal Area Network
WAN
Wide Area Network
MAN
Metropolitan Area Network
P2P
Peer to Peer
WWW
World Wide Web
URL
Uniform Resource Locator
URI
Uniform Resource Identifier
HTTP
HyperText Transfer Protocol
HTTPS
HyperText Transfer Protocol Secure
IP
Internet Protocol
TCP
Transmission Control Protocol
UDP
User Datagram Protocol
ISP
Internet Service Provider
DNS
Domain Name System
FTP
File Transfer Protocol
SMTP
Simple Mail Transfer Protocol
SNMP
Simple Network Management Protocol
SIP
Session Initiation Protocol
PSTN
Public Switched Telephone Network
WiFi
Wireless Fidelity
HTML
HyperText Markup Language
Data & Security
Abbreviation
Full Form
ASCII
American Standard Code for Information Interchange
UNICODE
Universal Character Encoding
OCR
Optical Character Recognition
OMR
Optical Mark Recognition
MICR
Magnetic Ink Character Recognition
PROM
Programmable Read Only Memory
EEPROM
Electrically Erasable Programmable Read Only Memory
ULSI
Ultra Large Scale Integration
AI
Artificial Intelligence
ML
Machine Learning
IoT
Internet of Things
VPN
Virtual Private Network
2FA
Two-Factor Authentication
SSL
Secure Sockets Layer
DDoS
Distributed Denial of Service
Digital India & Finance
Abbreviation
Full Form
UPI
Unified Payments Interface
NEFT
National Electronic Fund Transfer
RTGS
Real Time Gross Settlement
IMPS
Immediate Payment Service
NPCI
National Payments Corporation of India
AEPS
Aadhaar Enabled Payment System
CSC
Common Service Centre
e-NAM
National Agriculture Market
BHIM
Bharat Interface for Money
Computing History and Legacy Terms
Abbreviation
Full Form
ENIAC
Electronic Numerical Integrator and Computer
UNIVAC
Universal Automatic Computer
FORTRAN
Formula Translation
COBOL
Common Business Oriented Language
BASIC
Beginner's All-purpose Symbolic Instruction Code
DOS
Disk Operating System
IC
Integrated Circuit
WAIS
Wide Area Information Server
WORM
Write Once Read Many
VOIP
Voice over Internet Protocol
VSNL
Videsh Sanchar Nigam Limited
UMTS
Universal Mobile Telecommunications System
WBMP
Wireless Bitmap
WMA
Windows Media Audio
WMV
Windows Media Video
Quick Glossary Terms
Some important computer terms are not abbreviations at all, but they still appear as short factual references. It helps to keep them in one place with one-line meanings:
Term
Meaning
Response Time
The time a computer or system takes to respond to a command or request
Scroll Bar
A bar used to move up, down, left, or right through content on the screen
LISA
An early Apple personal computer remembered for popularizing the GUI idea in commercial systems
Dataphone
An early commercial modem reference associated with AT&T
Sunway TaihuLight
A Chinese supercomputer remembered as one of the world's fastest systems of its time
High-Frequency One-Line Terms from Exam Capsules
These quick definitions collect the small factual terms that often appear in old objective-question banks, glossary-style computer capsules, and one-line matching questions.
Term
Meaning
Access Time
Time taken to locate and retrieve data from memory or storage
Algorithm
A step-by-step procedure for solving a problem
Archive
A stored collection of files kept for backup or future reference
Backup
A duplicate copy of data kept for recovery
Bandwidth
The data-carrying capacity of a communication channel
Bar Code
Machine-readable pattern of bars and spaces used for identification
Bitmap
An image made of tiny dots or pixels
Blog
A regularly updated website or web page with posts or articles
Booting
The process of starting a computer and loading the operating system
Botnet
A network of infected computers controlled by an attacker
Browser
Software used to access and view websites
Buffering
Temporary storing of data in memory before processing or playback
Bug
An error or defect in a program
Cache Memory
Very fast memory used to store frequently accessed data
Clock Rate
Speed at which a processor executes cycles, usually in MHz or GHz
Compression
Reducing file size to save storage or transmission time
Cookie
Small data stored by websites in the user's browser
Control Panel
Windows utility area for changing system settings
Firewall
Security barrier that filters unwanted network traffic
Firmware
Permanent software stored inside hardware devices
Gateway
A device that connects different networks
Protocol
A set of rules for communication between devices
Surge Suppressor
Device that protects equipment from voltage spikes
Virtual Memory
Hard-disk space used by the operating system as temporary RAM support
