My B.Sc. Study Space

🧪 Chemistry — Major

Unit VII — Basic Computer System · Computer Fundamentals

Hardware, Software, Number Systems & OS

CompleteFundamentals of Chemistry

The parts of a computer, the binary world, and the operating systems that coordinate everything — the chemistry student's quick computer module.

Full notes

Definition: Hardware = the physical parts of a computer (CPU, memory, monitor, keyboard). Software = the set of programs that tell the hardware what to do.

1. Basic computer organization

  • Input devices: keyboard, mouse, scanner, microphone.
  • Storage: primary memory (RAM, ROM) and secondary (hard disk, SSD, pen drive).
  • Output devices: monitor, printer, speakers.
  • CPU = Control Unit + Arithmetic Logic Unit (ALU). CU directs operations; ALU computes.

2. Number systems

Computers work in binary (base 2) using bits 0 and 1. Octal (base 8) and Hexadecimal (base 16) are compact ways of writing binary. Example: decimal 26 = binary 11010 = octal 32 = hex 1A.

3. Codes

  • BCD (Binary Coded Decimal): each decimal digit in 4 bits (e.g., 9 = 1001).
  • ASCII: 7-bit code for characters — 'A' = 65, 'a' = 97, '0' = 48.

4. Operating systems

An OS manages hardware and software, provides the user interface and runs programs. Examples: MS-DOS (command line), Windows (GUI), Linux (open source, command-line + GUI), and mobile OS like Android/iOS.

5. Programming languages & software for chemistry

Low-level: machine language (0/1) and assembly. High-level: QBASIC, FORTRAN, Python. Chemistry software: ChemSketch (structures), SCI Lab, MATLAB, HyperChem (3D molecular modelling). Internet applications: web browsers, e-mail, e-learning portals (SWAYAM, e-content), research databases.

Note: Exam point: number conversion and ASCII/BCD are the most repeated; practise decimal↔binary↔hex.

Exam notes

CPU = CU + ALU. Binary 0/1; octal base 8; hex base 16. ASCII 'A'=65. OS = DOS/Windows/Linux. Languages: machine→assembly→high-level.

Important points

  • This unit is examined because the college syllabus includes it in the Chemistry paper — don't skip it.

Common mistakes

  • Writing binary for '26' incorrectly — divide repeatedly by 2 and read remainders bottom-up.
PreviousConformational Analysis: Ethane, n-Butane & CyclohexaneNext Differentiation, Integration & Logarithms