فصل 13. محطات العمل

بعد أن انتهينا من تجهيز المخدمات، يستطيع مديرو النظم التركيز على تثبيت النظام على محطات العمل الفردية وإنشاء إعداد نموذجي لها.

13.1. إعداد المخدّم X11

A brief reminder: X.org is the software component that allows graphical applications to display windows on screen. It includes a driver that makes efficient use of the video card. The features offered to the graphical applications are exported through a standard interface, X11 (Bullseye contains version X11R7.7).

منظور X11،‏ XFree86 وX.org

نظام X11 هو أكثر الأنظمة الرسومية استخداماً في نظم التشغيل الشبيهة بيونكس (كما أنه متوفر لنظامي ويندوز وMAC OS بالإضافة للنظام الأصلي). إذا أردنا الدقة، فإن المصطلح ”X11“ يشير إلى توصيف لبروتوكول فقط، لكنه يستخدم عملياً للإشارة إلى التطبيقات التي تحقق هذا البروتوكول.

X11 had a rough start, but the 1990s saw XFree86 emerge as the reference implementation because it was free software, portable, and maintained by a collaborative community. However, the rate of evolution slowed down near the end when the software only gained new drivers. That situation, along with a very controversial license change, led to the X.org fork in 2004. This is now the reference implementation, and Debian Bullseye uses X.org version 7.7.

Current versions of X.org are able to auto-detect the available hardware: this applies to the video card and the monitor, as well as keyboards and mice; in fact, it is so convenient that the package no longer even creates a /etc/X11/xorg.conf configuration file.

تضبط إعدادات لوحة المفاتيح حالياً في /etc/default/keyboard. يستخدم هذا الملف لضبط كل من سطر الأوامر النصي والواجهة الرسومية معاً، وتتحكم به الحزمة keyboard-configuration. تتوفر تفاصيل ضبط تخطيط لوحة المفاتيح في قسم 8.1.2, “ضبط لوحة المفاتيح”.

توفر الحزمة xserver-xorg-core مخدم X عام، كالمستخدم في النسخ ‎7.x من X.org. هذا المخدم تجزيئي ويعتمد على مجموعة من التعاريف المستقلة للتحكم بأنواع مختلفة عديدة من بطاقات الفيديو. يضمن تثبيت الحزمة xserver-xorg تثبيت مخدم x وتثبيت تعريف واحد على الأقل.

Note that if the detected video card is not handled by any of the available drivers, X.org tries using the vesa and fbdev drivers. VESA is a generic driver that should work everywhere, but with limited capabilities (fewer available resolutions, no hardware acceleration for games and visual effects for the desktop, and so on) while fbdev works on top of the kernel's framebuffer device. Nowadays the X server can run without any administrative privileges (this used to be required to be able to configure the screen) and its log file is then stored in the user's home directory in ~/.local/share/xorg/Xorg.0.log, whereas it is /var/log/Xorg.0.log for X servers started with root privileges and for versions older than Debian 9 Stretch. That log file is where one would look to know what driver is currently in use. For example, the following snippet matches what the intel driver outputs when it is loaded:

(==) Matched nouveau as autoconfigured driver 0
(==) Matched modesetting as autoconfigured driver 1
(==) Matched fbdev as autoconfigured driver 2
(==) Matched vesa as autoconfigured driver 3
(==) Assigned the driver to the xf86ConfigLayout
(II) LoadModule: "intel"
(II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so
(II) Module intel: vendor="X.Org Foundation"

إضافة التعاريف المملوكة

Some video card makers (most notably NVIDIA) refuse to publish the hardware specifications that would be required to implement good free drivers. They do, however, provide proprietary drivers that allow using their hardware. This policy is nefarious, because even when the provided driver exists, it is usually not as polished as it should be; more importantly, it does not necessarily follow the X.org updates, which may prevent the latest available driver from loading correctly (or at all). We cannot condone this behavior, and we recommend you avoid these makers and favor more cooperative manufacturers.

If you still end up with such a card, you will find the required packages in the non-free section: nvidia-driver for NVIDIA cards. It requires a matching kernel module. Building the module can be automated by installing the package nvidia-kernel-dkms (for NVIDIA).

The nouveau project aims to develop a free software driver for NVIDIA cards and is the default driver that you get for those cards in Debian. In general, its feature set and performance do not match the proprietary driver. In the developers' defense, we should mention that the required information can only be gathered by reverse engineering, which makes things difficult. The free drivers for ATI video cards, called radeon and amdgpu, are much better in that regard although it often requires non-free firmware from the firmware-amd-graphics package.