I can't honestly say what the Enhanced Real Tiem Clock is used for. A search for it on Google only mentioned sites that suggested compiling the kernel with it on/off for a specific feature to work.

There is some documentation in the kernel source as itsjustme pointed out, but I don't have access to my kernel tree right now, and I couldn't find any website that posts the kernel docs online.

Some might say this: it's "enhanced" which implies you have some access to a smaller set of utilities, and if your computer is working fine under normal use without the device present, then I don't see how its presence or absence should bother you.

I'm like you though, I'd still like to know exactly what I'm turning off. That's part of the mindset that makes LFS interesting in the first place.

yes i think this is the main reason why i use lfs instead of any distribution. i want to know what runs on my pc, why it runs and as good as possible what exactly it does...
i will browse through the man-pages. if i find something i will post it here.

I read over the rtc.txt file referenced earlier from a kernel source tree for version 2.4.18. The text of the file gives me the impression it has not changed in a LONG time, and is probably just as applicable to later versions of the kernel. "Get to the point Dark..."

Alright, the real time clock serves two main purposes:
1) To maintain the system time while the computer is off
2) To provide regular interrupts via the /dev/rtc device.

Obviously, you'll get #1 regardless of whether you run Linux, Windows, or any other OS since it's used when power is off.

#2 is only useful if you have a program designed to keep track of elapsed time using some other method that gettimeofday() functions and some other, non-specified routines. I'm not expert of how most programs are written, but the application for this seems small: real-time data acquisition. Stuff like that is usually meant for automated control external devices. Examples might be using your computer to control a servo hooked to a camera based on the amount of light available. There are other possibilities, but I think you're safe to remove it unless you plan to do real-time computing.

thank you, that is what i wanted to know about rtc ^^. i read the rtc-txt too but i didn't really unterstand most of it... now it's clear

but there is just a new problem:

im compiling kdelibs on my lfs-system but during configuration it breaks with the error: qt-libaries not found. but all libaries which are mentioned in the configure.log are in the right directory.

i guess that is all what does matter for this problem:
qt is installed in the directory: /opt/qt-3.1.2
a symlink points from /opt/qt to /opt/qt-3.1.2
in the ld.so.conf is the path: /opt/qt/lib

does anybody know what could cause this problem?

I believe there's a configure option for it... something like --qtlib-dir=/opt/qt... don't copy this character-by-character though, it might be better if you did a ./configure --help first to see whether what I submitted is correct.

Another possibility comes to mind. After you installed the libraries, did you update /etc/ld.so.conf? And if so, did you run ldconfig after that?

That and what Azmeen mentioned are the only things that immediately jump to mind.

so i have installed kde within the --with-qt-dir but the real problem is the /etc/ld.so.conf. it doesn't matter what i write in the ld.so.conf (and run ldconfig) when i start kde it breaks with many many: command not found statements. i think the ld.so.conf doesn't work alright... but why?

Alright, ld.so.conf is the PATH equivalent for libraries. If you're getting "command not found" errors, then that's something with your PATH; not ld.so.conf.

Write down which commands it says it can't find. Then search for the files:
find / -name "command name"

I'm willing to bet most, if not all, the commands it complains about are in the same directory. Then go edit your bash startup files to include that directory in your PATH environment variable.

i've added /opt/kde/lib to the path-variable and know it works. ~> the first time i can do something with my mouse in my own lfs ^^ cool feeling .

Excellent! Now all that's left is to start installing applications like a web browser. perhaps an office suite, and whatever else catches your eye...

so i need your help just another time...

how can i control how much colours are displayed by xfree86?
something is still wrong. the desktop looks as if there are to less colours displayed. everything seems a little bit grainy...

You'll need to modify your XFree86 config file. I believe it's typically located at /etc/X11/XF86Config-4

Look for a section titled "Screen" and in that section add a DefaultDepth line like:

DefaultDepth 16

That means you'll use 16 bits per pixel, giving a possible 2^16=65,536 possible colors on-screen at once. Just make sure you don't set it higher than what your hardware supports. If you do, then the screen will likely be a unusable, jumbled mess.

You might also want to specify your resolutions in the subsection corresponding to the default depth you chose.

You can see how the BLFS project does it at this link:
http://beyond.linuxfromscratch.org/v...x/xfree86.html

hm ok i try to ask more properly:

in the configuration file (in BLFS) there are approximately 7 or 8 SubSection's. in each of this subsections there is a line DefaultDepth ... should i delete all subsections except one?

i read on a bit in the chapter and there are many examples for window-systems and desktop envoirments. i'm using linux not that long so it's maybe a stupid question: what is a window system/desktop envoirment? - what does it, and what does it not? and where is the difference?

thank you for your quick answer

I don't remember the exact syntax of the file, but it looks something like this, right?

What the BLFS instructions want you to do is change the above to:

So, that tells "Screen" to use the subsection with 16-bit color depth as the default. Then you add the modelines in the subsection that matches the default you chose. The line I added is simply the more common resolutions. You could add more, take some out, whatever you want. As a side note, if you give more than one modeline, hitting Ctrl-Alt-<keypad plus> or Ctrl-Alt-<keypad minus> will cycle through the resolutions you specified.

Not a stupid question at all about the desktop environments. I'm just now becoming a little clear myself. GNOME and KDE are desktop environments. Essentially, they bundle everything you need together: window manager, file manager, menuing system, and a consistent interface to window/GUI system functions. The interface bit makes sure that if you write an application for GNOME, then anybody that runs GNOME will be able to run it. It's similar for KDE.

You don't NEED a desktop environment to have a GUI interface though. Personally, I'm setting up my system with XFree86 and a Window Manager of my own selection (Enlightenment: www.enlightenment.org). If a program is written to run under X, then it will run under my setup. In fact, I've got Mozilla and gkrellm compiled and running on my home system.

The trade-off is fewer ease-of-use features in favor of smaller size and greater speed. There's no menu panel in Enlightenment, but there are certainly fewer packages to install, and faster response because there is less overhead.

One caveat though: I cannot say with 100% certainty that KDE applications will run under a Window Manager only set-up. I've been told that all you need is to install the KDE libraries (or GNOME... whichever) and it SHOULD run under a Window Manager only setup, but I have not tried that yet.

I should also say that you don't have to use the window manager KDE or GNOME come with. You can change it after installation.

thank you xfree86 works now fine.

so there are just now more questions:
before i posted this reply i have searched in google for some of this questions but i found just so much that i didn't know where to begin.

1. i have problems setting up my network. especially the gateway. i am able to ping computers on my local network but i can't reach computers in the internet. i've followed all the instructions given by the lfs-book except the network-domain names. therefore they cause ip-adress conflicts. do you know what to do? a documentation for howto set up a network in linux (especially with windows and linux computers) would be nice

2. how can i change de picture repetition frequency in xfree86?

3. do you know something where i can read how to set up the /etc/fstab file properly?