how does an OS manage RAM?

[jackvdbuk]

its a question for my assignment (college level)

im trying to get some info on this but its a bit confusing/no proper good research have i found.

am i right in saying that an Operating system 'manages' the RAM by loading applications into the RAM and other WIndows Components aswell? but that dont really suit 'manage'

any help would be great!

EDIT: im havign a problem in word, when i highlight text, and press backspace, the text higlighted aint deleting..any ideas?? :S

[herulach]

You cant have looked that hard. First link in google:
http://www.memorymanagement.org/articles/begin.html

[jackvdbuk]

You cant have looked that hard. First link in google:
http://www.memorymanagement.org/articles/begin.html

lol cheeky, my searches was erm way off

thx alot!


what did you search for btw?

• Diagnose software and hardware problems

how on earth does an OS do that :S

programs like MemTest diagnose memory faults but how does an OS?

[ikonia]

he never searches.....but always claims he does.

[jackvdbuk]

no seriously i did, but just couldnt find anything proper!

with the linux thing, i didnt... i kno im bad n all but soz

nevermind, im going to do this by myself...

[chrestomanci]

http://www.oreilly.com/catalog/linuxkernel/

There should be a copy in your college libary.

[peterb]

Thanks, Chrestomanci, for that link - I've been pondering that book for while - might pop down to Waterstones and have quick browse before adding it to MY library!

[ikonia]

Peter, its a good book, very solid. Some chapters are covered right through from basic to advanced discussion.

Make sure you get the latest revision though as the older ones are quite out of date...to the point where they give wrong info.

I know you run RH9 which = old, but still, get the later revisions.

[peterb]

Peter, its a good book, very solid. Some chapters are covered right through from basic to advanced discussion.

Make sure you get the latest revision though as the older ones are quite out of date...to the point where they give wrong info.

I know you run RH9 which = old, but still, get the later revisions.

TVM!

[Agent]

am i right in saying that an Operating system 'manages' the RAM by loading applications into the RAM and other WIndows Components aswell? but that dont really suit 'manage'

Just a quick point here mate.
If it asks an operating system, dont say any specific ones. They can cost you marks dearly. Dont say "This is how Microsoft / Linux / Mac / RISC-OS / ect. manages RAM" - never mention brand names.

For example
Microsoft Word = Text editor
Excel = Spreadsheet
Photoshop = Graphics editing package
Outlook / Thunderbird = Email client
IE / Firefox = Browser

and so on....
You can loose a lot of marks for making this mistake at A level.

[chrestomanci]

Thanks, Chrestomanci, for that link - I've been pondering that book for while - might pop down to Waterstones and have quick browse before adding it to MY library!

It is a good book, I found a copy in the library at work, and read it over a period of a few weeks while I was waiting for compiles to complete and the like.

Some of the stuff in there is quite clever, for example, when a new process starts, instead of loading the executable binary into memory, the OS tells the memory manager that the executable is now another (read only) section of swap file. as the program executes part of it will be swapped in, but if it is a huge executable and the user used it for something simple then most of it will never get loaded. Conversely if there are lots of instances running, or the program gets run very frequently, the memory manager will keep it in memory making program start up fast and only consuming one lot of memory for all the instaces running. All this cleverness means that bloat is less of a worry on Linux, but makes it very hard to add up memory consumption as some shared libraries can be shared between hundreds of processes, but only be loaded once.

You might also look into the companion book Linux Device Drivers. That book has been released under the GNU free documentation licence, and you can download the entire text as PDF for free.

[jackvdbuk]

Just a quick point here mate.
If it asks an opperating system, dont say any specific ones. They can cost you marks dearly. Dont say "This is how Microsoft / Linux / Mac / RISC-OS / ect. manages RAM" - never mention brand names.

For example
Microsoft Word = Text editor
Excel = Spreadsheet
Photoshop = Graphics editing package
Outlook / Thunderbird = Email client
IE / Firefox = Browser

and so on....
You can loose a lot of marks for making this mistake at A level.

yes out of all the teachers only one says that, and its true, alot of my class mates say microsoft word instead of as you say Word Proccesor/text editor

[peterb]

....
I know you run RH9 which = old, but still, get the later revisions.

Just seen that the the Fedora Legacy Project is closing down, so it looks as if a move to FC might be in the offing soon. Pity as I'm really comfortable with RH9! (Bit like an old pair of walking boots that although not quite as trendy as the latest designs, still keep the cold and water out and fits like a glove!)

[peterb]

....
I know you run RH9 which = old, ...

Just seen that the the Fedora Legacy Project is closing down, so it looks as if a move to FC might be in the offing soon. Pity as I'm really comfortable with RH9! (Bit like an old pair of walking boots that although not quite as trendy as the latest designs, still keep the cold and water out and fits like a glove!)

Chrestomanci - thanks - I'll look at that too - although I think it will be a while before I ever get round to writing device drivers! I'm still learning scripting - "Classic Shell Scripting" is another book on my shopping list!

[chrestomanci]

Chrestomanci - thanks - I'll look at that too - although I think it will be a while before I ever get round to writing device drivers! I'm still learning scripting - "Classic Shell Scripting" is another book on my shopping list!

Personaly I would skip shell scripting and move straight to a proper scripting language like perl or python, as they are much more powerfull and the code is easier to read and understand.

Unix shell can do clever stuff, but only by using some horrible hacks, so unless you need to debug or maintain old shell scripts, I don't think there is much to be gained from learning.