Computer system

Lecture Overview

• Instructor: Dr. Harry Yu, Associate Professor in Data Science

• Co-Instructor: Dr. Youbing Zhao, Lecturer in Computer Science

What is Computer Systems?

• Refers to the integrated components that work together to process data and execute commands.

Key Components of Computer Systems

Central Processing Unit (CPU)

• Definition: Main component that executes program commands.

• Examples: Intel Pentium III, Sun Sparc Processor.

• Functions: Runs programs and processes data.

Main Memory

• Definition: Primary storage area for programs and data currently in use.

• Synonym: Often referred to as RAM (Random Access Memory).

Storage Devices

Main Memory vs Secondary Memory

• Main Memory: Fast access and temporary storage for active data and programs.

• Secondary Memory: Provides long-term storage; includes devices like:

  • Hard Disk: Magnetic storage, higher capacity.

  • Floppy Disk: Older storage, less capacity.

  • ZIP Disks, Writable CDs, Tapes: Various forms of removable storage.

• Data Transfer: Information moves between main memory and secondary memory as needed.

Input/Output Devices

• Definition: Allow user interaction with computer systems.

• Examples: Monitor, Keyboard, Mouse, Bar Code Scanner, Light Pen, Touch Screen, GPU.

Digital Representation

Bits and Combinations

• Bits: Basic unit of data in computing, represented as 0 or 1.

• Combinations per Bit:

  • 1 Bit: 2 combinations (0, 1)

  • 2 Bits: 4 combinations (00, 01, 10, 11)

  • 3 Bits: 8 combinations (000 to 111)

  • Each added bit doubles the combinations.

Representation of Data

• Each combination can represent a unique item.

• Formula: 2^N where N is the number of bits.

Memory Locations

• Definition: Main memory consists of numerous memory locations (cells) each with a unique numeric address.

• Address Examples: Cells might be numbered 9278 to 9286.

• Storage Units: Memory devices have specific storage capacities, measured in:

  • KB (Kilobyte) = 1024 Bytes

  • MB (Megabyte) = 1,048,576 Bytes

  • GB (Gigabyte) = 1,073,741,824 Bytes

  • TB (Terabyte) = 1,099,511,627,776 Bytes

CPU Functions

• Also known as Microprocessor.

• Working Cycle: Follows a fetch-decode-execute cycle:

  • Fetch: Retrieve an instruction from memory.

  • Decode: Determine the instruction's purpose.

  • Execute: Perform the instruction's action.

• Components of CPU:

  • Arithmetic Logic Unit (ALU): Performs calculations and decision-making.

  • Registers: Small storage areas for immediate data processing.

  • Control Unit: Directs the operation of the processor.

Networking Concepts

Network Connections

• Point-to-Point Connections: Each computer directly connected to all others; not feasible for larger networks.

• Shared Communication Lines: Most modern networks utilize this; adds ease to add new devices but may introduce delays due to traffic handling.

• Data Transmission: Information is sent in packets, which may be reassembled at the destination.

Types of Networks

• Local-Area Network (LAN): Connects computers over a small physical area, like a single room or building.

• Wide-Area Network (WAN): Connects multiple LANs over larger distances; often involves multiple organizations.

Protocols

• Definition: Set of rules governing the communication between networked devices.

• TCP/IP Suite: Key protocols for Internet communication.

  • Internet Protocol (IP): Specifies data format for transfer.

  • Transmission Control Protocol (TCP): Manages data flow and ensures complete message delivery.

Domain Names

• Structure: Domain names include a suffix indicating the organization type:

  • .edu: Educational institutions

  • .com: Commercial businesses

  • .org: Non-profit organizations

  • .net: Network organizations

• Country Indicators: Some suffixes indicate country of origin (e.g., .uk for the United Kingdom).

Conclusion

• Emphasis on the importance of understanding computer systems in both data science and computer science fields.