After 13 years, Addison-Wesley has published an update to a classic UNIX System programming text: Advanced Programming in the UNIX Environment. After the death of the original author, Rich Stevens, in 1999, it was difficult to find someone to tackle a project this big. We recently caught up with the co-author, Steve Rago, to get a behind-the-scenes look at this project.

Steve, you were one of the developers of UNIX System V Release 4. Can you tell us more about your background and contributions and how you became the co-author of the second edition of one of the most popular UNIX books?

After getting a BE and MS from Stevens Institute of Technology, I got a job working in the UNIX System V Development Laboratory at AT&T Bell Labs. I had wanted to work at Bell Labs, where my father worked, since I was 12 years old. Ironically, a year after joining Bell Labs, AT&T reorganized us into a different business unit, so we weren't Bell Labs anymore. I started out working on System V Release 2.0, helping to maintain and benchmark the VAX port. Eventually, I worked on networking software, which led me to STREAMS. After most of the original STREAMS developers completed the port of Dennis Ritchie's streams to System V Release 3, I ended up taking over responsibility for it somewhere between SVR3.1 and SVR3.2. During SVR4 development, I enhanced the STREAMS mechanism, converted the open file table to use dynamically-allocated memory (thus removing the historic NOFILE limit to a UNIX process's open files), moved the poll(2) system call under the vnode framework, and did a lot of general clean-up work in the kernel.

I spent 7 years at AT&T, then left for a small start-up company just before AT&T created USL. I worked on file systems, writing one that transparently compressed and uncompressed files on the fly, and another that sped up system throughput and used an intent log for fast recovery. These were eventually ported to the SCO OpenServer V UNIX System. Then I developed stackable file systems for commercial UNIX systems. The file system business evolved into a file server business, and then the company was bought by EMC, where I still work as a manager of one of the file system groups. In total, I have about 20 years of UNIX programming experience, both kernel-level and user-level.

Since I was involved in the review of the first edition of APUE, Addison-Wesley contacted me for suggestions for candidates to update the book. I wanted the book to be updated properly, the way Rich would have wanted, and to honor his memory, so I volunteered for the project.

Why did you update APUE and how does the second edition of APUE differ from the first edition? Where did you have the most changes?

Rich's book is a classic, but the world has changed a lot since it was first published in 1992. Standards have evolved, UNIX system implementations have come and gone, and technology has advanced significantly. I added a chapter on sockets, two chapters on threads, and totally rewrote the chapter on communicating with a printer to reflect the technological advancement from a serial PostScript printer to a network-attached PostScript printer. I removed the chapter that dealt with modem communication, but I made it available on the book's Web site. Other than the printer chapter, Chapter 2 shows the most change. It deals with standards, and these have changed significantly over the past 13 years. One other major change is that I shifted the implementation focus from 4.3+BSD and SVR4 to more contemporary platforms: FreeBSD 5.2.1, Linux 2.4.22, Mac OS X 10.3, and Solaris 9. (The source code for the examples is also available on the book's Web site.)

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