Can mkdosfs create bootable FAT like file system on linux? I don't know if mkfs.fat can create bootable a FAT file-system, but the man page says that can't. The plan is to create a small basic kernel with bootable FAT 12.

The man page says for mkfs.fat: mkfs.fat can not create boot-able filesystems. This isn't as easy as you might think at first glance for various reasons and has been discussed a lot already. mkfs.fat simply will not support it ;)

The options passed to format a bootable floppy:

mkdosfs -v -f 2 -F 12 -r 128 /dev/fd0

If you make the filesystem onto a floppy, you'd have to put an operating system on it to make it bootable.

If you make the filesystem onto a hard drive, flash drive, etc, you'd have to set up a basic partitioning scheme onto it, then install an operating system.

To do that would require more details, but the answer to your question is "no". Making the filesystem is only the first step in creating a bootable disk.

First, the partition that you are going to load the OS on has to be flagged as bootable (using fdisk). Next you need to install a bootable OS on that partition. See the source code for unetbootin for some good illustrations on how to do that. It will happily create a bootable USB stick from most any Linux live cd/dvd ISO file.