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Linux Migration: Page 3 of 9

Rather than represent different file systems with drive lettersas Windows does, Linux mounts everything in a subdirectory called a mount point, on the / (root) partition. So instead of a "C:" drive, you have a "/" drive, and instead of a "D:" drive (that you might use for data storage), you have a "/data" file system (see "Windows vs. Linux," right). The LSB may make you crazy at first, but remember that file systems, with the exception of the root file system, get mounted on subdirectories. What happens when you mount a file system on a directory that has files in it? Easy--those files aren't visible until you unmount the file system.

One major problem with early Unix efforts was file layout standardization. Fortunately, the LSB (Linux Standard Base), which specifies library interfaces, system-initialization standards and so on, came to the rescue. The LSB makes it easier to hire someone who is up to speed on your system even if he or she only has experience on a different distribution (see "Sites To See,").

In keeping with a healthy Unix tradition, however, just about everything is represented as a file in Linux, readable and writable by normal I/O operations. Most devices are represented as special file types, instead of Windows nomenclature like LPT1. Special file types let you rule in, or rule out, a subsystem in case of trouble: Ever send a print job to LPT1 rather than to the Windows spooler?

Device files are special types of files in the file system stored in the "/dev" subdirectory. Memory and all disk partitions are located in "/dev," so this subdirectory should be protected with the appropriate file permissions.

Another file system, "/proc," stores process status. It shows you the files opened by a particular process and which environment variables are set (PATH a nd other key variables), among other things. Having visibility into the process can help with troubleshooting.