Excessive RAM usage on boot - unnecessary modules?
 

I'm confused. Linux is supposed to be low resource, right? (For general usage anyway.) But when I boot, I'm already using over 300MB RAM. I only have 512, so that's a LOT. I'm running an old PC and that really bogs down my system. Here's a screenshot of Ksysguard right after I boot:

http://troop913.site40.net/temp/other/snapshot1.png

Even when I boot a resource hog like Win XP, it only uses 150MB on boot. I suspect there may be a lot of unnecessary modules loading, but I don't have much experience dealing w/LKMs (modules) and I don't know how to use modprobe etc. very well yet, so I don't know how to check what's loaded or how to remove/unload them (not sure what the proper terminology is for that). Any Ideas?

You have 512 Mb, so what is the problem? You can use 300 and you still have 212 free. You paid for the memory and if you don't use it, they won't pay back, so use it!
OK, if you really want to know, use the 'top' command. It'll give you an hint, but not the complete picture.
'linux' manages the memory and tries to consume as few as possible, but Debian is more than linux...
KDE also uses that memory, and Ksysguard does consume it as well. If you want to reduce memory usage (that is if you really need to, but you don't) do not to mix QT applications with GTK ones and don't use java, python or mono. Or just remove Xorg and run your system from the command line. Use links to surf the web and the mail command to send mails. That way, you can free up to 290 Mb.

Lol, well, the problem is that that's the RAM usage WITHOUT opening anything else. After I open iceweasel, icedove, skype, etc. and have been up for a few days, I'm using all my RAM PLUS 200MB swap.

Thanks, I'll mess around w/that top command.

Actually a lot of things are open when you launch KDE. There are processes related to kde-libs that are running to support other applications so they don't consume too much memory each.
I edited my post after you read it, sorry about that. If you are running KDE, only use QT applications and you should take advantage of the memory KDE tries to mutualize for other applications. Use opera or Konqueror instead of Ice-weasel, kopetee instead of skype and I don't know what icedove is (thunderbird?) but kmail is the equivalent of thunderbird. That way you can use much less memory. If you use a single gtk application, it involves allocating a lot of memory for all gtk applications but you have just one running. You might as well run several then. Don't use a single application that use Glib.
If you want a system that starts with low memory footprint but consumes a lot when you start launching applications, don't use KDE, but XFCE, LXDE, JWM, and there are dozens and dozens of other DEs.

If modules are loaded, you probably need most of them. Further more, I'm not sure removing some will make a big difference.

Useful commands anyhow:
lsmod # to know wich modules
rmmod <module_name> # typed as root, to remove a module if it is not in use
modprobe <module_name> # typed as root, to insert a module and it's dependencies

If you want to forbid automatic launching of a given module at boot time, try to add or uncomment an entry for it in /etc/modprobe.d/blacklist: "blacklist <module_name>". Bear in mind though that this won't prevent loading the module manually or inside a script.

[Edit]You will be better of using a window manager like fluxbox instead of KDE. You still will be able to use all KDE apps.

It's doubtful that it's a module problem. I'm running Debian Lenny and, booted running Firefox, I'm using just under 200MB RAM. You've got something else happening. Look at your process table to see what you've got going on. Do you have Compiz or something else that's high-usage running?

Wow, I've never gotten so many replies so quickly on a forum before!

Thanks for your explanation, Agrouf. I didn't realize that so many things were loaded in KDE even if they weren't being used atm. I'll definitely look into using a different DE. As for not using ANY DE, I'd love to, but there's a few things I still like it for. For example, I do some online college classes that include watching instructional videos (for which I also need JavaScript). Are there any CLI browsers that allow this? W3m doesn't...

What's QT? I've heard of it, but it's kind of an abstract "thing" atm - not sure what it is. Also how do you know if an app uses GTK or QT etc.? (lol sorry - I posted this in the newbie section for a reason!) Thanks for your patience.

Thanks Quakeboy02. I've already checked to make sure there's nothing extra hogging the memory, so it must just be KDE.

I'm glad to know it's not the modules... I don't really feel like messing with that.

Random question - Are there any good CLI IM/Chat clients? I'm currently using Skype and Gizmo. Those and Firefox/Iceweasel are the two main reasons I still use a GUI (I love my addons...).

EDIT: While we're talking about it, what's the best CLI email client? I've messed with mutt a little, but not enough to be proficient with it yet.

CLI? I dunno. I used xchat when I had a need for it.

I think the ksysguard graphs are including the filesystem cache (probably the orange coloured bit).

Run 'free' from a konsole, and check the '-/+ buffers/cache:' line to see what you're really using.

Dave

Double post (again - anyone else getting these?)

What IS the filesystem cache? I don't understand what that and the buffer is. Any good learning resources where I can read about it?

Did you run "free"?

lol, whoops, missed that part. Thanks.

Well, atm I'm experimenting with jdm, xfce, fluxbox, openbox, lxde, etc. Pretty cool stuff imo. I'll keep messing with different ones for a while I guess.

Hi again.

Good overview of the FS cache here:
http://linux.about.com/od/lsa_guide/a/gdelsa44.htm

I think mutt's the best text mode mail client - it's a bit clunky straight out the box, but once you play with .muttrc , you can get it to do pretty much whatever you want. Never used any CLI chat clients, though.

Dave

I believe the orange part is the 'user' memory while the other part is the 'system' memory, whatever that means.
Anyway, running everything from the CLI is a bit extreme in my opinion. If your system is responsive you don't need to worry about the memory. 512 Mb of RAM is more than enough to run a good DE without using the swap at all. You should experiment with lighter DE if your computer is slow but running everything from the CLI and using 12Mb of RAM when you have 512 is a waste of resources in my opinion. You should run something that consumes at least 350 Mb of RAM or that mean that you are wasting your RAM. Try XFCE, KDE 3 or GNOME. That should run fast enough on your computer, unless you bought it in 1975.