Guide of Scifir

Starting guide of informatics

Edition: Publication date: 2024-02-21 Authors: Ismael Correa C. Categories: start, informatics

Computing and informatics

Computing means the area of knowledge about devices that do computations, that’s, math calculations and logical calculations. Informatics means the area of knowledge about information. Both words are used as synonym but are, then, different. Computers do both things at the same time, which are different tasks and have different purposes and utilities.

Open source software

Open source is a concept created by Richard Stallman that means software whose code is freely available for everyone. Open source software is always free to download and use. When you have various options of software to use, if you don’t want to spend money buying private software, you can always look for open source alternatives, which are free. Also, it’s common that open source software is better than commercial software in lots of software categories, so they tend to be the better choices available.

History of informatics

The first computer, which is the first turing machine, has been created by Alan Turing. The first important operating system, UNIX, has been created by Dennis Ritchie and Ken Thompson. The first important programming language, C, has been created also by Dennis Ritchie. Previous to C, the programming languages were COBOL, Lisp, Fortran, among others.

The second computers, after the UNIX systems, have been created by Apple and Microsoft in similar years.

Units of information

A bit is a unit of information that can be one of only two different values, a 1 and a 0. A byte is composed of 8 bits. Each byte can store 256 different values, and only one of those values at the same time. Bytes operate in binary, because each bit can only be a 1 or a 0, and it can’t be any other value. Although it’s possible to create computers that work with units of information different than bytes, that’s, units of information with more or less than 8 bits, that is not in use nowadays, and all computers operate in bytes of 8 bits.

The prefixes for bytes are in the order of 1024 instead of in the order of 1000, in difference with meters, forces, and a lot of other SI units. The SI units are the International System of Units and include all the standardized units, as meter, forces, pressures, volumes, etc.

A kilobyte, abbreviated KB, has a total of 1024 bytes. A megabyte (MB) a total of 1024 KB. A gigabyte (GB) a total of 1024 MB. A terabyte (TB) a total of 1024 GB.

Files and directories

Both files and directories are stored inside hard disks. They are stored inside a hard disk through a system named filesystem. A file is an entity of a filesystem that containts information that can be read, saved, updated and removed. The information can be read directly, as is the case of a plain file, or it can be archived with some software, as tar files. There’re also binary files, which contains instructions to be executed directly by a processor.

The most popular filesystems today are NTFS and ext4. NTFS is the filesystem used by Windows and ext4 is the generic filesystem created for open operating systems, like Linux distributions.

Codification of characters

To codify means to assign a code to something. This code is used, in informatics and in other disciplines, as replacement of the information the code is of, it’s like a synonym and it’s equivalent in all purposes to the real information the code represents.

Inside informatics, all the characters of the keyboard, and ll the characters that aren’t appearing as key directly in the keyboard, are codified. The codification systems most used are UTF8, UTF16 and UTF32.

UTF8 characters size 1 byte. Then, when writing, 12 UTF8 characters size in total 12 bytes.

UTF32 characters size 4 bytes. Then, 12 UTF32 characters size in total 48 bytes.

UTF16 characters are characters that can be UTF8 characters or UTF32 characters. Then, they size 1 byte per each UTF8 character plus 4 bytes per each UTF32 character. When writing, if there are 10 UTF8 characters and 2 UTF32 characters, the size of the 10 UTF8 characters will be 10 bytes, and the size of the 2 UTF32 characters will be 8 bytes, making in total 18 bytes for those 12 UTF16 characters.

All UTF codification schemes are managed by the informatics organization called Unicode. In their website, all Unicode codification schemes can be seen, there’re a big amount of different Unicode alphabets. The alphabets available are all the alphabets that exist, including chinese, russian, japanese, arab, persian, thai, and even ancient egypt (that’s, jeroglyphs).

File formats

A file format is a format for storing data inside a file. A file follows a file format if it doesn’t breaks it, that’s, if it follows the rules of the file format. If the file format is correct, then a program that opens that file format can read the file and use it for the any purpose the program allows.

File formats common to all operating systems:

File formats used by Windows operating systems:

File formats used majoritarily by Linux distributions, although also in all other operating systems:

Hardware characteristics

Hardware components

Inside a motherboard there are included the following components, impossible to separate from it:

Hardware peripherals

Plug and play, abbreviated PnP, means that a peripheral can be connected to a computer and used instantly, without needing to configure it or to restart the computer.

Hardware accessories

Hardware ports

The internal ports are the following:

The peripheral ports are the following:

Hardware brands

How to mount a computer

The first action to do is to attach the motherboard to the chassis, use the screws that come with the motherboard to attach it to the chassis.

The next set of actions to do is to connect all the hardware components to the motherboard. First add the processor to the socket. After that, add the thermal paste in top of the processor and then add the cooler in top of the processor, the thermal paste then should be between the processor and the cooler. Add the RAM memory to the RAM sockets. Add the graphics card to the PCI express. Add all the hard disks to the SATA ports. Connect then the power supply, by connecting first to the central electricity of the motherboard. Then, add the power supply connectors to the hard disk and to the graphics cards.

Now that all the hardware components are connected, close the chassis and attach the hardware peripherals. Attach the mouse, the keyboard, connect the ethernet cable, connect the monitor and the speakers.

Keyboard keys

Computer networks

Network connections

The Internet Service Provider (ISP) is the organization, usually a company, that provides the internet connection through a subscription. A network modem manages the network connections of all computers of a LAN, like for example a house, and sends them to the Internet Service Provider. A router is another name used currently as synonym for modem.

Operating systems

Windows

Operating system created by Microsoft. It has had various versions, which are Windows 1, Windows 2, Windows 3, Windows 95, Windows 98, Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8, Windows 10 y Windows 11.

A application, in Windows, is every program that appears with a graphical user interface, that’s, inside a window. A service, in Windows, in contrast to applications, is every program that’s executed in the background, without showing a graphical user interface of it. A process, that’s, a set of instructions executed by a processor, in Windows, can be different to an application and also different to a service and, so, strictly, all the processes that Windows executes aren’t necessarily an application or a service. All the internal parts of the operating system of Windows are executed by processes, too.

The desktop, inside Windows, is where the direct accesses of the applications appear and can be started from there.

The task manager allows to stop programs and services. It also shows the consumption of CPU and RAM. It’s executed by typing Alt+Ctrl+Supr.

Android

Operating system for embedded systems managed by the Open Handset Alliance. It’s an operating system of generic purpose that adds sensors and all important technologies utilities to embedded systems to allow it to do everything currently invented by informatic technologies. Android devices can then do calls, connect to internet, send voice messages by internet, measure the temperature, recognice voice, recognice faces, among a wide amount of features. Android is centrally used for smartphones, but it can also be used for any other electronic device, of any kind.

UNIX

Operating system created by Dennis Ritchie and Ken Thompson. It’s the first operating system created and it’s the operating system with very high trascendence that has shaped the informatics. It has had the first shell, called in his first version the thompson shell, and the C compiler, called cc, the build program called make, among many other essential programs that together have created the start of the informatics era.

The filesystem of a UNIX operating system is composed of the following folders:

The principle of UNIX says that each program should to one task good, a no more than one kind of task.

Linux

Linux is a kernel that allows to create operating systems. A kernel is the central part of an operating system, it contains the process scheduler, which is the central part of the kernel and is the part that controls the execution of processes. The different parts of the Linux kernel are called modules. The process scheduler is one of the modules, the others manage for example the input and output that processes can do, the signals between processes, and the drivers of the hardware of the computer. The modules of the Linux kernel can be installed and updated by using the command line.

An operating system created using the Linux kernel is called a Linux distribution. Linux is open source software and then it can be used freely by anyone to create an operating system for any purpose. A Linux distribution implements over the Linux kernel a desktop environment that allows to use the operating system. The most important desktop environments for Linux are GNOME, KDE plasma desktop and LXQT.

The most common Linux distribution, which uses GNOME, is Ubuntu. The most important Linux distribution usually is considered Debian. Fedora and KDE Neon are other important Linux distributions. All Linux distributions are composed of packages, which are files that contains one or more software, with, usually, their respective documentation. The most common extensions of Linux packages are deb and rpm. All Linux distributions contains different packages by default. It’s that difference in the packages they contain what makes each Linux distribution unique related to the other Linux distributions.

iOS

BSD

Family of operating systems that are a variant of Linux operating systems that allow to change everything of them. They are open source and in their open source license they allow any change. Then, BSD operating systems can be used for any purpose, and be customized for any need, of any electronic device. It has been used for videogame consoles, and for a wide amount of electronic gadgets, due to it enormous versatility.

The web

The web is the set of all websites linked by urls between them. A website is an entity that contains any number of webpages. A webpage is a digital page that contains information in the form of enriched text, images, videos, among any other interaction.

The acronym www means world wide web.

The web is managed by the W3C, called World Wide Web Consortium.

Common programs

Windows

The first collection of programs to know in Windows is Microsoft Office, which includes a good amount of programs to do different paper work and related tasks.

Linux distributions

Important informatics

Important organizations and businesses of informatics