Re: Linux? Which one is the most friendly?

From: Moe Trin (ibuprofin_at_painkiller.example.tld)
Date: 05/06/05 

Date: Fri, 06 May 2005 14:33:57 -0500

In article <1115346616.821833.55140@f14g2000cwb.googlegroups.com>, Greg wrote:

>..... keep in mind im 14... =D i dont know if that came as a shocker
>but the 91 in my name is 1991 for my birthyear...

So most likely, your total computing experience has been windoze. Well,
things existed before then.

>>Consequently, they get swapped out over the first night,

[compton ~]$ uptime
 12:22pm up 135 days, 4:53, 20 users, load average: 0.00, 0.00, 0.00
[compton ~]$

We tend to leave the systems run continuously.

>> as the kernel sees them not in use, and the newly available space is
>> used for file/disk caching.

*nix is a multi-user multi-tasking operating system (those 20 users are
all me, doing different things in different terminals).

[compton ~]$ ps aux | grep -cv USER
81
[compton ~]$ ps aux | grep -c '('
25
[compton ~]$

That's one of my home systems. The first command says there are 81 applica-
tions running at the moment. These include everything from running those
commands and the shell they are run in, on down to the system logging
daemon, several server applications and daemons, and so on. Being an old
dinosaur, I do virtually all of my work from the command line, and while
I am running 'X' (the GUI desktop), there isn't an icon or taskbar in
sight. I can access additional logins by pressing the Ctrl, Alt and one
of the first six function keys - which bring up additional login screens.
Generally, I don't use them, but they are running if I need them. The
kernel notices that they aren't being actively used, and has swapped them
out to disk where they remain available. (The second command is looking
for process listings that contain a parentheses, which is how swapped
out processes are displayed - here 25 of the 81 noted above.) Nearly all
of the RAM that they were using are then made available for other jobs.
One such job is remembering what things I've done lately (for example,
programs that I have run, directory listings, data used by previous tasks
such as the spelling dictionary), and if the data isn't kept in memory,
the pointers necessary to find that data quickly is cached. This makes
jobs or applications I am doing run faster. We don't have to wait for the
kernel to grab the data off the disk - it's right here, right now.

>> Unused memory is a waste - put it to use.

One of the most common questions a new user has is 'what happened to all
of my memory?'. You may discover the 'free' command and use it shortly
after your computer boots. Depending on how much "stuff" you have
running, you may see 6 to 100 Megs of RAM being used (yes it can easily
vary that much). You say "that's nice", and go do other things - surfing,
reading news, who knows. Later, you'll run the 'free' command again, and
lots more of the RAM is now in use, but you aren't doing anything more than
you were earlier. If you leave your computer up overnight (most distributions
run housekeeping tasks at oh-dark-thirty when few users are competing for
CPU cycles and memory), you'll see even more memory is "in use". Why?
It's because the kernel is caching more data that it expects you will want
to use. "You used that data before, you'll probably use it again."

>? Sorry but i dont completely understand.

To get the best use out of anything, it helps to know what it's doing, and
why. Despite what you may have experienced in the past, computers really
are complicated. A measure of this complication is the huge amount of
documentation that is supplied with your system. I'd mentioned the HOWTOs
earlier. This system has 489 documents, totalling about 4 million words.
There are things called 'man pages' which mean 'manual' pages. This system
has about 4300 documents in the man pages, and there are more called 'info'
pages (only another 60 on this system).

[compton ~]$ whatis whatis
whatis (1) - search the whatis database for complete words
[compton ~]$ apropos whatis
apropos (1) - search the whatis database for strings
whatis (1) - search the whatis database for complete words
[compton ~]$ whatis man
man (1) - format and display the on-line manual pages
man (7) - macros to format man pages
man [manpath] (1) - format and display the on-line manual pages
man.config [man] (5) - configuration data for man
[compton ~]$

'whatis' and 'apropos' is searching a database created by those overnight
housekeeping jobs. To access these manual pages, you would use the command
'man man' or 'man whatis' and so on. The info pages are reached with the
info command ('info info' brings up the info page on 'info', just as 'man
man' brings up the man page for man).

        Old guy

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