Lecture Notes: High-Level vs Low-Level Programming Languages

Introduction to Programming Languages

• Programming dates back to the dawn of computer science.
• Early computers were controlled by electrical cables and programmed with plug boards and wiring.
• Programs were complex to set up, taking days and altering only every few weeks.
• Initially, programs were written in binary on paper tape.

Low-Level Languages

• Developed to simplify programming compared to binary.
• Assembly Language:
  • Allowed programmers to use simple commands translated into machine code.
  • Mapped closely to machine architecture and specific processors.
  • Described as being "close to the hardware."
  • Efficient in speed and memory usage due to direct memory manipulation.
  • Required significant intellectual effort due to complexity and difficulty in understanding.
  • Still used for embedded systems and device drivers.

High-Level Languages

• Emerged to make programming more understandable and less hardware-dependent.
• Examples: Short Code (1949), Python, C, Java, BASIC, Visual Basic.
• Characteristics:
  • Represents instructions in a more understandable form, like English.
  • Translated to machine code by a compiler or interpreter.
  • One source instruction can translate into multiple machine instructions.
  • Higher abstraction allows for easier and faster coding.
  • Less memory efficient and potentially slower execution if not optimized.
• Historical Use:
  • Grew as CPUs became faster and memory increased.
  • Personal computers used high-level languages for non-critical speed applications.
  • High-level languages proliferated over the last 60 years for diverse purposes.

Comparison Summary

• Machine Code:

  • Binary representation of instructions.
  • Directly executed by the CPU.

• Low-Level Languages (Assembly):

  • One-to-one translation to machine code.
  • Hardware-specific; works on one processor type.
  • Direct memory work; difficult to understand but efficient.

• High-Level Languages:

  • Require compilers/interpreters.
  • Platform-independent; run on different processors.
  • Easier to write and understand; less efficient if not optimized.

Conclusion

• Assembly language still has niche applications.
• High-level languages dominate current programming due to ease of use and abstraction.
• Understanding both types is essential for understanding computer operation and programming efficiency.