Task 5.

Study new words and word combinations from the Text 3:

Изучите новые слова и словосочетания из текста №3:

Command Line Interface – интерфейс командной строки

switches – опции, включающие или выключающие какие-либо параметры программы (параметры программы)

shell – оболочка

credentials – учетные данные

kernel – ядро

allocate – выделять, устанавливать, e.g. – allocating CPU time and memory to processes – выделение ресурсов ЦП и памяти различным процессам

terminal emulator – эмулятор терминала

third party emulators – сторонние эмуляторы

extended file system – расширенная файловая система

journaled file systems – файловые системы с ведением журнала (протоколированием); журналируемые файловые системы

Text 3: Overview of Linux and os X cli

In both Linux and OS X, the user can communicate with the operating system by using the command line interface (CLI). To add flexibility, commands (or tools) that support parameters, options and switches, are usually preceded by the dash ("-") character. The options and switches supported by a command are also entered by the user along with the command.

A program called a shell (оболочка) interprets the commands from the keyboard and passes them to the operating system. When a user logs in the system, the login program checks the username and password; if the credentials are correct, the login program starts the shell. From this point on, an authorized user can begin interacting with the OS through text-based commands.

As shown in Figure 1, users interact with the kernel through a shell. In other words, the shell acts as an interface layer between the user and kernel. The kernel is responsible for allocating CPU time and memory to processes. It also manages the file system and communications in response to system calls.

Most operating systems include a graphical interface. Although a command line interface is still present, the OS often boots into the GUI by default, hiding the command line interface from the user. One way to access the command line interface in a GUI-based operating system is through a terminal emulator application. These applications provide user access to the command line interface and are often named as some variation of the word terminal. On Linux, popular terminal emul-ators are Terminator, eterm, xterm, konsole, gnome-terminal. OS X includes a terminal emulator called Terminal but a number of third party emulators are available.

Linux and os X File Systems

Linux and OS X have unique file systems.

The commonly used file systems in Linux are ext3 and ext4 (third and fourth extended file system). They are journaled file systems that keep journals, or logs, of all the changes about to be made to the file system. These journals minimize the risk of file system corruption in the event of a sudden power loss because the journals can be used to apply the changes after power is restored. Both file systems can support large file sizes up to 32 TiB (tebibytes) for ext4.

HFS+ (Hierarchical File System Plus) is the principle file system used by OS X. Like ext3 and ext4, HFS+ also supports journaled volumes. HFS+ volumes can support large file sizes up to almost 8 EiB (exbibyte) in OS X 10.4 and later.

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