ASCII and Unicode | JKSSB Mock Test
Introduction
Have you ever wondered how computers understand letters, numbers, and symbols? Behind the scenes, every character you type is stored as a number. This is made possible by systems like ASCII and Unicode. These standards play a vital role in how digital text is stored, displayed, and transmitted. Let’s explore what they are and how they differ.
What is ASCII?
ASCII (American Standard Code for Information Interchange) is a character encoding standard that assigns numeric values to 128 characters including English letters, digits, and special symbols.
Key Features of ASCII:
- Uses 7-bit encoding (values from 0 to 127).
- Covers basic English characters only.
- Efficient for simple text processing.
- Examples: 'A' = 65, 'a' = 97, '0' = 48.
Limitations of ASCII
- Cannot represent non-English characters like ₹, ñ, or 汉.
- Limited to 128 characters only.
- Not suitable for global languages and symbols.
What is Unicode?
Unicode is a universal character encoding standard that assigns unique codes to characters in almost all writing systems worldwide.
Key Features of Unicode:
- Uses up to 32 bits to represent over 1 million characters.
- Supports nearly all languages: Hindi, Arabic, Chinese, Tamil, etc.
- Backwards compatible with ASCII (first 128 codes are the same).
- Examples: 'A' = U+0041, 'अ' = U+0905, '€' = U+20AC.
Unicode Encoding Formats
- UTF-8: Variable length (1–4 bytes); most widely used on the web.
- UTF-16: Uses 2 or 4 bytes; efficient for non-Latin scripts.
- UTF-32: Fixed 4 bytes; simple but memory-heavy.
ASCII vs Unicode: A Comparison
| Feature | ASCII | Unicode |
|---|---|---|
| Character Range | 0–127 | Up to 1,114,112 characters |
| Bit Length | 7 bits | 8, 16, or 32 bits |
| Language Support | English only | Supports all global languages |
| Encoding Type | Fixed | Variable (UTF-8), Fixed (UTF-32) |
Why is Unicode Important Today?
- Enables cross-language communication on the internet.
- Supports multilingual applications and websites.
- Facilitates emoji and symbol encoding.
- Ensures data consistency across platforms.
Real-Life Applications
- ASCII: Source code, email headers, command-line tools.
- Unicode: Webpages, word processors, databases, mobile apps.
Exam-Oriented Quick Facts
- ASCII bit size: 7-bit.
- Unicode introduced: 1991.
- UTF-8 is the most used Unicode encoding online.
- Unicode includes ASCII as its first 128 characters.
- ASCII is limited to English and control characters.
Conclusion
Understanding the difference between ASCII and Unicode is essential for anyone dealing with text, coding, or computer applications. While ASCII laid the foundation, Unicode is the future of multilingual computing. Whether you're developing apps or preparing for exams, this knowledge is both practical and crucial.
Know your codes. Communicate globally!
