I'm making a case for running linux on one of our servers.

The selling point to the boss will be the shared memory. Windows 2003 has a 4GB limit, of which 1GB is used by the kernel, I understand. (with /3GB switch in boot.ini)

with linux, I'm hoping that I can set the shared memory to much much more - the full memory which is 6GB - which would allow us to run a java application and oracle on the one box - with the promise of more physical memory if this works ok.

so, the things I need to check out are:

1. The distribution I'm planning is debian. can that be set so the shared memory is the physical memory in the machine?

2. shared disk space. The plan to sell this to the boss is to dual boot the server, windows and linux. If I have a shared disk space, which is about 100GB, what formating should be used so that both O/S can access it? I plan to run the applications off this shared partition, with linux and windows on their own seperate partitions.

thoughts appreciated, pointers to further info appreciated.

Thanks,

1. Shouldn't be a problem. And AFAIK, the Linux kernel isn't going to take up a GB of memory. Linux also utilizes RAM and Memory better than Windows, way better that is. It doesn't release memory just cause it doesn't use whatever application or service any longer, it will cache until its either needed again or another program can use it instead, etc.

2. For this, you should just look into using something like vmware. If this is a production type server or development, you shouldn't ever need to dual boot to have different environments, setup your Linux install and then run a Windows virtual OS with vmware, it's rather cheap and will save the company time, money and resources, never having to reboot just to get to another OS... have them both readily available at all times..

thx, in fact, thats what one of the other engineers here suggested!

first i have no idea how windows works but the ideas you present about RAM can be somewhat misleading.

32-bit architectures can reference only 4 GB of physical memory.
each running process has access to this virtual 4 GB and it is generally divided up into 1 GB for kernel and 3 GB for user space.
(In Linux it is possible to alter this to 2/2 or whatever)

The kernel virtual area (3 - 4 GB address space) maps to the first 1
GB of physical RAM. The 3 GB addressable RAM available to each process
is mapped to the available physical RAM.

Linux and i would imagine windows as well use the Page Table Extensions available in the processor to map the physical RAM above 1 GB into this scenario. It's a hardware thing and nothing can be done about it.