Introduction to Computer Science (CSC 111)

Study Notes

Lecture Overview: The lecture will cover computer software, operating systems, application packages, exercises, and assignments.

Definition: Software is a computer's set of programs. These programs provide instructions for the computer to perform tasks. They are the instructions given to the computer, and a collection of them make up software.

System Software: Programs that run computer hardware and application software.
- Examples: Operating systems (like DOS, Windows XP, Vista, Unix/Linux, macOS), utility software (file management like Windows Explorer, compression tools, virus protection, disk tools, etc). Language Processors (compiler, interpreter, assembler).
Application Software: Programs that handle specific tasks for users.
- Examples: Word processing (e.g., Ms. Office 2003, 2007), graphics programs (e.g., Macromedia Dreamweaver, Flash, Freehand, Adobe PageMaker, Photoshop), specialized software (school management systems, inventory management, payroll systems, financial systems).

Definition: A platform that manages and coordinates resources for a computer, handling interaction between the user and hardware.
It hosts the numerous programs running, regulating and managing their sharing of hardware resources.

Processor Management: Controls how the CPU and other processors are used.
Memory Management: Manages how RAM is used by programs.
File Management: Manages how files are stored and accessed.
Device Management: Controls how input/output devices (the keyboard, mouse, monitor, printers, etc.) work.

Real-time Operating System (RTOS): Aims to execute real-time applications. Used in critical systems that need timely responses (nuclear power plants, oil refining, chemical processing, traffic control).
Single User Systems: Designed for single user at a time. Most desktop operating systems fall into this category (Example: DOS).
Multi User Systems: Support multiple simultaneous users. Often found in mainframes or time-sharing systems. (Example: Unix)
Multi-tasking and Single-tasking: Multi-tasking systems allow multiple programs to run at once, whereas single-tasking systems only run one program at a time.
Distributed Operating System: Manages a group of independent computers, making them appear as one. Allows distributed computing, better performance, is easily scalable and offers resource sharing

UNIX: Popular multi-user, multi-tasking operating system created in the early 1970s, using C programming language and able to be used on many systems.
LINUX: A free and open-source OS based on Unix. This allows use on many platforms such as personal computers and Macintoshes.
Windows: A series of graphical operating systems by Microsoft, introduced in late 1985 (as an enhancement to MS-DOS), that dominates personal computer market.
Solaris: Unix-based OS, originally by Sun Microsystems, now owned by Oracle after their acquisition.
BOSS (Bharat Operating System Solutions): A GNU/Linux distribution by C-DAC (Centre for Development of Advanced Computing), for enhancing open source software use, placing particular emphasis on desktop security features.

Definition: Programs that manage, maintain, and control computer resources. Operate at the lower level to handle issues and management not covered by the operating system.

Types: Word processing, spreadsheets, databases, presentations.
Custom/User Software: Programs developed to address specific user requirements.