Introduction to Computers

Study Notes

A computer is an electronic device for calculating, analyzing, and presenting data. It solves problems by applying prescribed instructions.
A computer is made up of hardware (physical components) and software (programs and operating systems).
It performs tasks such as processing data, storing, and retrieving information, communicating with other devices, running applications, and accessing the internet.
Types of computers include desktops, laptops, tablets, smartphones, servers, and supercomputers.

Computers perform numerous functions and their use varies by user group.
Initially, computers were used for scientific and military applications, primarily for calculations, especially in wartime.
Today, computers are used for a vast array of tasks across numerous fields.
General computer functions include data storage, calculations, analysis, and controlling devices.

Speed: Computers process data quickly and accurately, often at nano or picosecond speeds.
Access: Computers allow for quick access and retrieval of stored information.
Security: Computers have built-in security measures to protect data from unauthorized access.
Storage Space: Computer memory can store large amounts of information.
Automation: Computers automate repetitive tasks.
Communication: Computers enable easy and fast communication.
Versatility: Computers can perform a multitude of tasks.
User-Friendliness: The design of computers generally makes them easy to use.
Scalability: Computers can be upgraded and expanded as needed.
Cost-Effectiveness: Computers can reduce labor costs and increase productivity.
Data processing: Computers efficiently handle large amounts of data.

Computers are categorized in various ways based on size, processing power, purpose, and usage.
The categorization includes supercomputers, mainframe computers, personal/microcomputers, and minicomputers.
Attributes of each type (e.g size, portability, processing power) distinguish one from another.

Hardware: The physical parts of a computer, such as input devices (keyboard, mouse), output devices (monitor, printer), internal components (CPU, RAM), storage devices (hard drives, SSDs).
Software: Programs and applications that tell the computer what to do. These include operating systems, application software, and utility software.
Firmware: Small programs that keep the hardware running smoothly.
Data: Raw information processed and stored by the computer.
People: Users and operators interact with the computer and input data and instructions.
Connectivity: Hardware and software that enable communication between various devices and networks.

An operating system (OS) is a set of programs that manages the computer's hardware and software resources.
It controls various aspects like booting, memory management, data security, process management, and input/output functions.

Computer security protects computer systems, networks, and data from unauthorized access, use, disclosure, and disruption.
Key aspects of computer security include confidentiality, integrity, and availability.
Common threats include viruses, worms, trojans, malware, spyware, adware.
Methods like firewalls, anti-virus software, encryption, and user awareness help mitigate threats.

Primary storage (RAM, ROM) holds data and instructions that the CPU directly accesses.
Secondary storage (hard disks, SSDs) stores data permanently and is generally slower than primary storage.
Tertiary storage (external hard drives) may be used to store larger amounts of data. Online cloud storage services are also widely used.

Computer languages allow humans to communicate with computers.
Different types of languages exist, including high-level languages, low-level languages (machine code), assembly languages, and markup languages.
Software translators like compilers, interpreters, and assemblers convert code between different language types making it easier for human interaction and processing by the computer.

Source code is the human-readable code written using a programming language.
Object code is a machine-specific code produced from the source code that is ready for execution by the CPU.
Source code needs to be translated to object code before execution.