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Introduction to Computer
Systems and Programming
Fundamentals
Overview of Computers and Programming
Computers are electronic systems designed to transmit, store, and manipulate data. Data encompasses numeric, character, graphic, and sound formats. A program, which is a set of instructions, is required for a computer to manipulate data. This course focuses on writing such programs.
Types of Computer Systems
Computer systems include mainframe computers, laptops, notebooks, netbook computers, and tablets.
Components of a Computer
(The text does not specify the components, but implies they exist.)
Input/Output Devices
Input/Output devices include keyboards, mice, cameras, microphones, scanners, monitors, printers, speakers, headphones, plotters, and projectors.
Computer Networks
A Local Area Network (LAN) connects computers, printers, scanners, and storage devices via cables, Wi-Fi, or Bluetooth for intercommunication. A Wide Area Network (WAN), such as the Internet, connects computers and LANs across a large geographic area.
Operating Systems
An operating system (OS) is system software that manages computer hardware and software resources, providing common services for computer programs. Loading the operating system is called booting.
Application Software
Application software is used for specific tasks like word processing, accounting, database management, web surfing, email checking, gaming, movie watching, or weather forecasting.
Storage/Memory Types
CPU registers provide a small amount of fast storage for the processor. Random-Access Memory (RAM) is the main memory, containing billions of cells with direct access for data and programs. Secondary storage includes hundreds and thousands of billions of cells on magnetic and optic disks, flash drives, and cloud storage.
Memory Cells and Addresses
RAM is divided into memory cells, each having an address representing its relative position in the computer's main memory. Memory cells store information, either program instructions or data.
Internal Representation Terminology
A bit is a binary digit (0 or 1). A byte is a group of 8 bits. A word is the width of a register. Each byte of main memory has an address.
Memory Cells and Addresses (Details)
Memory cells are organized in multiples of 8 bits (bytes). A character can be stored in one byte, an integer in four bytes, and a floating-point number in either four bytes (single precision) or eight bytes (double precision). Each byte in memory has an address expressed with four or eight bytes. A 32-bit (4 byte) system has a maximum memory capacity of 4GB. Due to address bus limitations, computers often have addresses ranging from 36 to 40 bits, resulting in a more realistic maximum of 64GB memory, although 16GB to 24GB are more common upper limits due to cost.
Binary System
Counting in binary is similar to decimal; when you run out of digits, you use two digits. Padding with zeros to the left does not change the value (e.g., 00001001 is the binary equivalent of 9).
Integer Numbers (Unsigned)
All numbers are converted to binary in memory. For example, 9 = 1001. In a 32-bit system, 9 would be represented as 0000 0000 0000 0000 0000 0000 0000 1001. The number is placed on the right, and unused bits are padded with zeros.
Integer Numbers (Signed)
Modern computers use two's complement to represent negative numbers. This can be achieved by starting from the right, finding the first 1, and inverting all the bits to the left of that one (e.g., 1111 0111).
Brute Force Algorithm
The most basic type of algorithm. Example: The factorial of a number builds on a simpler case like 5! is actually 4! + 5.
Writing an Algorithm
Imagine solving the problem without a computer and write English sentences to explain the solving process.
Programming Languages
3rd generation (3GL) languages are more human-friendly (e.g., C, Fortran, Java, Python). Example: y = x * x + 2; print (x); 4th generation (4GL) languages are closer to human languages (e.g., find all car colours where brand is “Audi”). 5th generation (5GL) languages are artificial intelligence languages using facts and rules (e.g., Prolog, Lisp). Example: capital(Ottawa,Canada).
Solving Problems
The text mentions steps required to solve a problem with a computer program, but does not list them.
Professional Ethics
Computer programmers and software engineers need to follow standards of professional conduct.
