I've only been toying with Linux for a couple of weeks off and on. But I've got a not-so-newbie task to accomplish.

I'm trying to setup a very tiny PXE boot of Slackware. I want it to boot via PXE and run off a root filesystem contained entirely in a ramdisk (because later I'm going to be completely trashing/redoing the hard disks on the machines).

I've got PXELINUX working and kinda figured out how to compile a kernel (but that still needs lots of fine tuning). I want to compile into the kernel as much as I can so I don't have to worry about modules at this point.

What I'm having trouble with is setting up the root file system. I've kinda figured out what needs to be done as far as setting up a loopback device, and getting files into and out of it, gzipping it up, and getting that into a ram disk.

But my problem is--exactly what files and directories do I have to put on the root file system? At a minimum I need to be able to get to the network and map back to Windows Shares (using mount -t smbfs....). How does one figure out which files and dirs are needed and which can be deleted?

As far as basic shell commands go, probably the simpliest way to get what you need is to use Busybox. You'd need to add smbfs to the kernel of course. I'm not sure if a samba client would be required or not for you mount smb shares using mount though, but I don't think so. But mount is included in Busybox, as are most all of the networking tools. You can find out what support files a binary requires by starting it with "strace". You can list required libraries for a dynamic binary using "ldd".

Anyway, you may want to have a look around the net. Most likely someone has already created a bootdisk close to what you need. I know there is one called "Bart's Bootdisk" but I believe it is MSDOS. If a CDROM is available, you could use something like Knoppix or one of the other smaller CD distros as well.