da nuitari » mer gen 02, 2008 6:36
ecco un altro pezzo.
PLZ aiutatemi, devo capire se sto buttando via il mio tempo o cosa.
=Rudiments=
==Consoles and Virtual Terminals==
In information technology, with "console" u mean a combination of hardware device (usually called "terminal") and software compontents needed to interact with a system.
Within a normal Personal Computer, the hardware side consists in a couple of keyboard/monitor, the software side consists in a textual interface (CLI, Command Line Interface). In modern PC, the console pourpose is mainly administrative.
Usuallu, trough the console will be displayed startup information, system messages and status, or simply will be launched applications and environments (like graphical ones, called Desktop Environments).
Concerning Linux, it's possible to do nearly everything within the console. Considered however that the physical terminal arranges a relatively limited space for the display of the information (a monitor), is very easy to feel "squeezed". In order to bypass this limitation, Linux implements the so-called "Virtual Terminals (or Console)" (between the much types of console that support), whose purpose is allow to perform on the same physical terminal more instances of the console, each connected to a virtual terminal, allowing switching with the pressure of some simple Hot-Keys (ALT+F1, ALT+F2, etc).
Using virtual consoles will be possible, for example, to carry out in a console the conversion of a mp3 while in another console u can give an eye on the CPU utilization with an appropriate tool, while in another console a client will be downloading torrents. For a Linux userm, this way to operate represents the normal computer utilization, even if it is to all of the effects of a conquest, appraising the terminal'history in the information technology.
==The VGA Console==
How said, the device normally used to display the console is the monitor. In fact, the monitor serves only "to project" what the true device for the video management realizes: the graphic adapter, or video card.
Historically speaking, a considerable quantity of graphic adapters (everyone with an own standard and own features) are existed. While the graphic adapter's quality grew, the monitor's quality grew equally (near ever).
Between all standards that in time have succeeded (CGA, EGO, etc), the VGA standard (made by IBM) was the first one to unanimously be accepted and implemented from near all hardware and software companies, spreading itself to the such point than by now is the common minimum denominator that the personal computer should have for the display management. It's enough to think about a so widely spread operating system like Windows that start visualizing splash screen in VGA format without not even take in consideration the hypothesis that the hardware can not support it.
The main features of the VGA standard, useful to this article, are a maximum resolution of 640x480 pixel (the pixel for who did not know is an individual rappresentabile point on screen) and a maximum depth of 256 colors at 70hz refresh, with the possibility to operate on the screen as a character's matrix (text fashions) or a point's matrix (APA, All Points Addressable) for the display of graphics.
Linux implements the possibility to use the console on devices in graphic VGA for the virtual console with the ''vgacon'' driver, the normal low resolution console that all we are used to, and that. Except different indications, the Linux kernel load vgacon as the default driver for the system console (read next chapters). The vgacon driver allows using the console only in the textual mode.