some questions -- plz help linux system v, getty, security...

[Maaz]

Dear All

following are some questions
1) what is System V ?
2) is Linux a System V compatible ?
3) what is c1, c2 and c3 level security ?
4) what is getty ? and GETTY-1-3
5) what is Initial Program Loader(IPL) ?
6) what is vm linuz, window kernel, and memory kernel ?
7) and in last what is initrd ?

Plz reply/help me ... so that i know.

Regards
Maaz

[David Child_1 · Accepted solution]

Maaz,

Many of these questions would take a great deal of typing. Here are some general answers. Your best bet is to seach the web or get some good Linux books;

1. System V is a major version of Unix. For a detailed timeline go to: http://www.unix.org/what_is_unix/history_timeline.html at the bottom there is a chart.

2. No, System V is Unix. Linux works like Unix in many respects (and most utilities work like their System V counterparts, but some work like their BSD counterparts).

3. These are US Department of Defense defined levels of security. For a server to have C2 level of security it must pass certain requirements. A short background can be found at: http://www.unix.org/what_is_unix/history_timeline.html

4. "getty is a program that is invoked by init(1M). It is the second process in the series, that ultimately connects a user with the system". It is a program that is run on the system that will get your terminal, etc. set up so you can log in. Try "man getty".

5. IPL is just that. It would be too hard (and too inflexible) to load the entire kernel directly during a system boot. Instead the server loads the IPL which in turn finds the actual kernel and loads that (among other things).

6. vmlinuz is a compressed version of the vmlinux kernel. It is bootable. This is the actual operating system kernel.

7. From http://www.linuxforum.com/linux-filesystem/initrd.html:
"initrd provides the capability to load a RAM disk by the boot loader. This RAM disk can then be mounted as the root file system and programs can be run from it. Afterwards, a new root file system can be mounted from a different device. The previous root (from initrd) is then moved to a directory and
can be subsequently unmounted."

[Maaz]

Dear David Child, I m highly Thank ful to u for the info u provide.

Thankx n Regards
Maaz