Preface

p. xviii

The statement about SunOS 4.1.x was probably not even true when Stevens was finally published: it is certainly not true now (not least because 4.1.3 had some serious Year 2000 issues). Among UNIX-based implementations, Linux is almost certainly the most popular (by number of hosts) on the Internet. However, a large number of web servers etc. are still based on Suns, running, in general, Solaris 2.6, 2.7 or 2.8. The vast majority of machines on the Net these days¹ are running Windows of some flavour, now that Windows is shipped with TCP/IP. Stevens' statement that most of the serious research is done with Berkeley-derived systems is still true, though.