How do you use RAM disk?

[Madseel]

Ok. Ive read and heard about this RAM disk, and i know what it is, but, how do you do it?
Thanks.

Madseel

[MrLinus]

What operating system do you want to set it up in?

You'd use it for things you don't want to keep on the local disk. My boyfriend used to have a RAM disk setup for his netscape browsing so that anywhere he went on it didn't stay on the hard drive.

[slarty]

Ram discs are essentially filesystems that store files in memory (rather than on a physical device), hence are very fast and lose their contents once the machine is turned off. The former property is useful for temporary files that are very frequently accessed, and the latter is useful for security programs that don't want sensitive data to go on to a physical medium which it can subsequently be recovered from.

Under DOS, there is a ramdisk shipped (I think DOS 5 and higher), called ramdrive.sys (if memory serves). You have to load it from config.sys and then an extra drive letter appears. It uses DOS expanded or extended memory (you can configure the size).

Under Windows there clearly must be some ram discs, but there isn't a standard one and I don't know of any.

Under Linux there are at least two ram discs. One is the classic "ramdisc" driver. You have to make a filesytem on it first, then mount it, for example

mkfs.ext2 /dev/ram0 1440
mkdir -p /mnt/ram
mount /dev/ram0 /mnt/ram -t ext2

Would mount a 1.4Mb ram disc under /mnt/ram. Note that the memory stays used after you unmount it, and it uses memory even if empty.

On newer Linux kernels, there is a second ramdisc. This is cleverer. You don't need to prepare it at all, just mount away

mount none /mnt/ram -t tmpfs

And a dynamically sized ramdisc magically appears in /mnt/ram. The really clever thing is that it only uses up as much memory as the files that are in it (it has a limit though - it won't exhaust your memory)

As soon as you unmount it, the files are gone, never to return, and the memory is freed.

Bear in mind that under any OS, if you have swap enabled (i.e. virtual memory), then the "secure" contents of a ramdisc might end up in your swap file, so be warned!

[Networker]

That's good info, Slartly!
I am glad I read your post.

I have a question how do you use that temporary RAM disk? For instance to avoid web server buffer overflow consequences. Can we imagine on Linux to have dedicated RAM & Flash memories to data and processes for a http server?
I guess that overflowing temporary dedicated RAM buffers will not compromise processes running on the standard RAM.

[Zonewalker]

If you're on windows and you want a RAMdisk driver go to this place...

http://www.arsoft-online.de/products/

download the AR RAMdisk driver. Make sure you read the readme file very thouroughly. This setup requires a bit of work from you and the readme is detailed enough for you to set this up on your PC.

Slarty I don't know if you run Windows at all (I know your v big on linux) but if you do the second link might interest you more as it has links to two other places (apart from the above link) where you can d/l drivers for RAM disks under windows. Anyway once you have the RAMdisk installed and working go to the following website

http://www.surasoft.com/tut/ramdisk.htm

this place gives you details of how to use the RAMdisk for storing index.dat and temp internet files on. Follow the instructions to the letter.

MsMittens... you're b/f used to have a RAMdisk... why not anymore??

[MrLinus]

My boyfriend upgraded to OS X from OS 9 and never looked into it. .. Lazy boy!

[slarty]

Originally posted here by Networker

I have a question how do you use that temporary RAM disk? For instance to avoid web server buffer overflow consequences.

Using a ramdisk will neither prevent not cause web server buffer overflows. In fact it will have no effect.

Can we imagine on Linux to have dedicated RAM & Flash memories to data and processes for a http server?
I guess that overflowing temporary dedicated RAM buffers will not compromise processes running on the standard RAM.

I don't really know what you mean. Ramdiscs are used on many small Linux distributions (for example Freesco) as the root filesystem and to store most files - so the original files can be stored compressed and modifications can still be done.

Running out of a ramdisk will not prevent any buffer overflows, or stop an attacker who gains some undesirable level of access from running amok.

[the_JinX]

you could make a webserver without any kind of harddisks alltogether..

check out locustworld they have nice WAPs (Wireless Access Points) without harddisks

[Madseel]

Ok. Thanks you all. I was looking for both linux and windows by the way.
Are there any other ways too?