Computer - a machine that can be programmed to automatically carry out sequences of arithmetic or logical operations (computation). Technically a computer doesn’t need to be electronic, nor even have a processor, RAM or hard disk.
With old computers, most didn't have GUIs, usually they had no mouse, touchscreens. So to interact with the computer, the command line would allow you to enter commands and fire the keyboard, the computer would interpret and execute these commands, terminal is an application that gives you access to this command line so that you can run commands via the keyboard. Terminal is used to look at network issues, hardware, navigating the OS, to open other apps, create and remove files, etc.
There are various kinds of computers
Exascale computing - refers to computing systems capable of calculating at least 1018 IEEE 754 Double Precision (64-bit) operations (multiplications and/or additions) per second (exaFLOPS)"; it is a measure of supercomputerperformance. Exascale also reaches the estimated processing power of the human brain at the neural level, a target of the now defunct Human Brain Project.There has been a race to be the first country to build an exascale computer, typically ranked in the TOP500 list.
Supercomputer - a type of computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second (FLOPS) instead of million instructions per second (MIPS). Since 2022, supercomputers have existed which can perform over 1018 FLOPS, so called exascale supercomputers. For comparison, a desktop computer has performance in the range of hundreds of gigaFLOPS (1011) to tens of teraFLOPS (1013).Since November 2017, all of the world's fastest 500 supercomputers run on Linux-based operating systems.
Mainframe Computer - informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise resource planning, and large-scale transaction processing. A mainframe computer is large but not as large as a supercomputerand has more processing power than some other classes of computers, such as minicomputers, servers, workstations, and personal computers.
Microcomputer - is a small, relatively inexpensive computerhaving a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (PCB).
Minicomputer (historical) - or colloquially mini, is a type of smaller general-purpose computer developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors.
Motherboard - main PCB or printed circuit board in general purpose computers.
Before printed circuit boards, electrical circuits were wired point to point on a chassis. In electronics point-to-point construction was used heavily before PCBs were invented.
Breadboard - in electronics a breadboard, protoboard are construction bases used to build prototypes of electronic circuits. Breadboards don't require soldering like a perfboard or stripboard.
An electronic component is a basic electronic device that is part of an electronic system used to effect electrons and their associated fields.
Electronic circuit - consist of electronic components like resistors, transistors, capacitors, inductors and diodes.
Daughterboard - an expansion card that attatches to the system directly. Also called mezzanine cards.
Server - a computer that provides information to other computers called cilents over a computer network. Cilents and servers can communicate over a computer network on seperate hardware but the cilent and the server can also be on the same device
Processor - an electrical component that performs operations on an external data source.
Co-processors - such as graphic processing units (GPUs). Some other coprocessors are physics processing units (PPUs) which are used to make physics related calculations mainly in video games, digital signal processors (DSPs) like IPUs or ISPs (image processors).
Process - the instance of a computer program that is being executed by one or many threads.
Central Processing Unit (CPU) - The main processor in a system.
RAM - Random-access memory
Flash - a form of computer memory that retains content when its power is removed, flash memory has a limited amount of P/E cycles (program and erase) between 500 and 100,000
SSD - Solid State Drive, almost all SSDs store data in NAND flash, early SSDs were based on SLC or single level cell technology, storing one bit of information per cell, SLCs are expensive and are usually made for servers.
NAND - "Not and" logic gate
MLC - multi level cell, storing two bits of data per NAND flash cell, it wears out quicker. They come in a few variants, enterprise or eMLC and end-user MLC drives. eMLC have lower writing speeds so they last longer. The average eMLC SSD is about 10,000 to 30,000 P/E cycles, and the end-user MLC about 3,000 to 10,000 cycles.
TLC - triple level cell, lowers the price but has a lower P/E cycle rating, about 500 to 2,000 P/E cycles in its lifetime.
QLC - quad level cells.
A lot of SSD companies give SSD endurance ratings, for example, PBW or petabytes written, a petabyte is 1,024 terabytes. There is also DWPD or drive writes per day, which measures the number of full P/E cycles that can be done to an SSD every 24 hours. In end-user SSDs, it's usually written in TBW or terabytes written.
Multitasking - the concurrent execution of multiple tasks (processes) over a certain amount of time.
Bits - a bit, or binary digit, is the smallest unit of data that a computer can store and process.
Nibble (computing) - In computing, a nibble, or spelled nybble to match byte, is a unit of information that is an aggregation of four-bits; half of a byte/octet. The unit is alternatively called nyble, nybl, half-byte or tetrade. In networking or telecommunications, the unit is often called a semi-octet, quadbit, or quartet.
Byte - a unit of data that's made up of eight binary digits, or bits.
Kilobyte - one kilobyte is about 1,000 / 1,024 bytes.
Gigabyte - a gigabyte is about 1 billion bytes of data.
Firmware - software that provides low-level control of computing device hardware. For a relatively simple device, firmware may perform all control, monitoring and data manipulation functionality. For a more complex device, firmware may provide relatively low-level control as well as hardware abstraction services to higher-level software such as an operating system. Firmware is found in a wide range of computing devices including personal computers, smartphones, home appliances, vehicles, computer peripherals and in many of the integrated circuits inside each of these larger systems. Firmware is stored in non-volatile memory – either read-only memory (ROM) or programmable memory such as EPROM, EEPROM, or flash. Changing a device's firmware stored in ROM requires physically replacing the memory chip – although some chips are not designed to be removed after manufacture.
Liquid-crystal display - (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers to display information. Liquid crystals do not emit light directly but instead use a backlight or reflector to produce images in color or monochrome. They are used with things like smartphones.
ARPANET - The Advanced Research Projects Agency Network (ARPANET) was the first wide-area packet-switched networkwith distributed control and one of the first computer networks to implement the TCP/IP protocol suite. Both technologies became the technical foundation of the Internet. The ARPANET was established by the Advanced Research Projects Agency (now DARPA) of the United States Department of Defense.
Internet - a global system of interconnected computer networks that uses internet protocol suite (TCP/IP)
Intranet - a private network (as opposed to the public networks of the internet) used for sharing information, easier communication, operating systems, and other computing services within an organization usually with the exclusion of outsiders.
Extranet - a controlled private network that allows access to partners, vendors, suppliers, or an authorized set of customers, normally to a subset of the information accessible from the organization's intranet.
Virtual Private Network (VPN) - a network architecture for virtually extending a private network across one or more other networks that are untrusted (not controlled by the entity aiming to implement the VPN) or need to be isolated. The goal of a VPN is to allow network hosts like PCs and servers to exchange network messages across another network to access private content, as if they were part of the same network.
Ethernet - a family of wired computer networking technologies commonly used in local, metropolitan and wide area networks.
Arduino - makes programmable circuit board, plug it into computer with USB C and programmable with C++, makes many thing with electricity that isn’t a smart device.
Raspberry Pi - can run home servers, don’t have to plug into a computer, a computer itself, you can run various operating systems on it like Ubuntu and various Linux based.
A brick (or bricked device) is a mobile device, game console, router, computer or other electronic device that is no longer functional due to corrupted firmware, a hardware problem, or other damage.
Operating system - a system software that manages computer hardware and software resources, and provides common services for computer programs.
Network - There are different kinds of networks. Circuit switched networks are used for things like an analog telephone with a physical wire. Public switched telephone networks deal with the aggregates of the world's telephone networks. PSTNs are operated on a local, regional or national level. Computer networks are systems that connect multiple computing devices.
Routing - the process of traffic selection in a network or between many networks
IP - The internet uses the Internet Protocol, among other things. It is a network layer or layer 3 of the OSI Model.
Internet protocol suite has layers like the OSI Model. There are four layers, the application layer, the transport layer, the internet layer and the link layer. The link layer is the lowest of these levels.
IPv6 - The most recent version (2025) of the Internet protocol.
IPv4 - Internet Protocol Version 4, was exhausted in the 2010s.
Geofeed - is list of IP address ranges associated with geolocation information. The principle was authored by Google in July 2013. Starting August 2020, it was officially published as a standard under RFC 8805 with the name A Format for Self-Published IP Geolocation Feeds. This is now the gold standard for sharing geolocation information. Geofeeds are used to correct data errors that result from altered prefixes or other variables that affect geolocation. Network operators can publish a mapping of IP address ranges to simplified geolocation information, informally termed a geolocation feed or geofeed. Interested parties (e.g. geolocation providers but not only) can regularly poll and parse these feeds to update or merge data with other geolocation data sources and then apply procedures with very little hassle. At Ipregistry, we check and merge geofeeds daily.
Nanoscale - a set of interconnected nanomachines that perform only simple tasks like computing, data storing, sensing and articulation.
Near-field (NFC) - a set of communication protocols that enable communication between two electronic devices over a distance of 1.6 inches or less.
The Secure Element chip, an NFC chip that contains data such as the Secure Element identifier (SEID) for secure transactions. This chip is commonly found in smartphones and other NFC devices.
Body - a wireless network of wearable computing devices, BAN devices may also be embedded inside the body as implants or pills.
Personal - a computer network for interconnecting electronic devices within a person’s individual workspace. PANs provide data transmission among devices like computers, smartphones, tablets and personal digital assistants. A wireless personal area network deals with things like IrDA, Bluetooth, NearLink ro Zigbee. Universal Serial Bus (USB)
Near-me - a grouping of communication devices that are in close physical proximity to each other but not necessarily connected to the same communication network infrastructure.
Local (LAN) - a computer network that interconnects computers with a limited area like a residence, school, laboratory, university campus or office building.
Storage (SAN)
Wireless (WLAN) - a wireless computer network that links two or more devices using wireless communication to form a LAN within a limited area like a home, school, campus or office building.
Virtual (VLAN)
Home (HAN)
Building
Campus (CAN) - a campus area network or corporate area network is a computer network made up of an interconnection of local area networks within a limited geographical area. The networking equipment, such as switches, routers, and the transmission media, like optical fibers, copper plant, Cat5 Cabling is owned almost entirely by the campus, enterprise, university, etc. A CAN is larger than a LAN but smaller than a MAN or WAN. Some examples of CANs are Stanford University Network, Project Athena, Andrew Project, and the networks at Googleplex.
The range of CANs are 1 - 5 km or 0.6 miles to 3.1 miles.
Backbone - a part of a computer network that interconnects networks providing a path for the exchange of information between different LANs or subnetworks. Usually the backbone’s capacity is more than the networks connected to it.
Metropolitan (MAN) - a computer network that interconnects users with computer resources in a geographical region the size of a metropolitan area. The interconnection of LANs in a city into a single larger network that may also offer efficient connection to a WAN.
Municipal Wireless (MWN) - a citywide wireless network
Wide (WAN) - A wide area network covers a large geographical distance but also usually involves leased telecommunication circuits.
Cloud - Internet area network (IAN)
Code - an algorithm that uniquely represents symbols from some source alphabet, by encoded strings, which may in some other target alphabet.
Closed source - the source code isn’t available to the public, it’s only accessible to the organization that developed it or those who pay access to it. Some closed source softwares include Microsoft Windows, Adobe Photoshop, Apple IOS and Microsoft Office.
Open source - the source code is available for the public, so anyone can read or modify it. Open source software is often free. Some open source softwares are Linux, WordPress, Mozilla Firefox, Apache, and Android.
Linux’s predecessors were:
Unix (1970s) (developed by AT&T Bell Labs)
Posix (the standardization of Unix) (Portable Operating System Interface) - made to insure other systems would be compatible with each other.
Minix (was made for academic use)
Linux (1991) (made by Linus Torvalds) - free to distribute, modify and sell to others. Referring to the operating system kernel.
Kernel -
Mac OS, Android, Free BSD and Linux are all mostly Posix compliant.
Operating systems segregated by country:
OpenKylin (China)
BharOS (India)
Astra Linux (Russia)
Canaima (China (Inspur))
Nova (Cuba)
Red Star OS (N. Korea)
MARKUP LANGUAGES
Basic (Dartmouth, 1964)
Scratch
JavaScript
Python
Specialized dynamic high-level languages:
Bash
Powershell
Lua (Brazil, easier and faster than Python. Embedded into engines like Roblox and WOW)
Ruby (Japan, object-oriented language)
Julia (2009, MIT) used for scientific computing
Static high-level languages:
Java (runs on a JVM, syntactic dumpster fire)
C Sharp (used for Unity games)
Typescript (2012, USA)
Kotlin (2016, Czechia, Android)
Swift (2012, USA, IOS)
Dart (Flutter framework)
Go (developed by Google to build low-level systems, designed as a replacement for C, 2009 USA)
Functional languages:
Haskell (1990, global, inspired by the Miranda language, named after the mathematician)
F sharp (also imperative and object-oriented)
Scala
Clojure (functional and dynamic)
Ocaml (1995, France, used extensively with Facebook)
Elixir (ruby-like syntax)
Elm (purely functional language, 2002 Harvard, complies to JavaScript)
Low-level systems languages:
C
C++
Rust
Modern languages:
V (2019, Netherlands, high-performance systems language similar to Go and doesn’t use garage collector or like Rust doesn’t use borrow checking)
Zig (2016, USA, simplifies low-level programming)
Nim (2008, Germany)
Carbon (supposed to be a successor to C++, 2025)
Solidity (2018, global)
Hack
Historically important languages:
Fortran (1957)
LISP (1958)
ALGOL (1958)
Cobol (1959, over 40% of banking systems still use it, and 2 billion lines of code still in production today)
APL (A programming language)
Pascal
Simula
Erlang (1986, Sweden, basically powered the entire telecom industry)
Ada (1977, USA, general purpose language)
Prolog
ML (Meta language)
Esoteric (joke) languages:
INTERCAL (1972, USA)
Brainfuck (1993, Switzerland)
Malbolge (1998)
Chef (2002)
Shakespeare (2001)
PIET
LOL code (2007)
Emojicode (2016)
Holy C
Lowest level:
Assembly (1947)
Machine Codes / Raw Binary
Transistors (1947, on a CPU)
Quantum Electrodynamics (1927)
Python vs C/C++ vs Assembly side-by-side comparison
Python is an interpreted programming language
C and C++ are compiled languages which get optimized during compilation
Assembly is just sequence of instructions labeled with names typeable on a Latin keyboard. It isn't optimized or whatever
Front-end Development: Involves HTML, CSS, JavaScript for the user-facing side
Back-end Development: Involves server-side technologies (e.g., PHP, Python, Node.js)
Databases: Used for storing website data (e.g., MySQL, MongoDB).