1.9 Use of these notes

These notes, which are intended to supplement the comments already present in the source code, are not essential for understanding the UNIX operating system. It is perfectly possible to proceed without them, and you should attempt to do so as long as you can.

The notes are a crutch, to aid you when the going becomes difficult. If you attempt to read each file or procedure on your own first, your initial progress is likely to be slower, but your ultimate progress much faster. Reading other people’s programs is an art which should be learnt and practised because it is useful!