Difficult I would say. I had to understand several systems to port the FreeBSD WiFi stack. Had to learn how FreeBSD network subsystem is working and how Haiku's existing compat layer emulates the behaviour of its archetype. Than I had to understand how the FreeBSD WiFi stack works and how it interacts with the networking subsystem. Ofcourse Haiku's network subsystem had to become second nature to me, too.
Last but not least there was the 1000 pages IEEE Std 802.11 document, where I had to learn how to navigate it for retrieving the information I needed (meaning had to read it from top to bottom).

After the port was running on my setup, there was the testing stage. The main mission for that was to further stabilize the port. Luckily there were many testers providing me bug reports. To understand and fix/answer those bugs thoroughly I had to delve in several other subsystems (PCI, Interrupts) and topics (PCI-Express, PCMCIA/CardBus). A dense debugging week with Joe Prostko come to my mind here, where we interchanged possible fixes and new syslogs to get down to the problem. His atheros card neither receiver nor send any data. At first it seemed that this was caused by missing PCI Express support in Haiku. After that was ruled out, there were interrupt storms so I assumed some interrupt routing problems with his netbook.

In the end we figured that it was due to reading the interrupt status register twice, where the Haiku driver used the value of the second read, the originial FreeBSD code used the first one. So the second read always returned 0 on his hardware meaning: I didn't caused this interrupt, try the next device on the interrupt chain. This experience made me to heavily comment two lines in the atheros driver's glue code.

This testing was limited to atheros based WiFi chipsets, though, as there were still several components missing in Haiku's FreeBSD compat layer to port the remaining WiFi drivers, too: firmware loading, condition variables and some higher level synchronization functions to name the most prominents.

Besides those very WiFi specific hurdles in achieving the "brought Wifi to Haiku" there was all the learning about the jam build system, the coding guidelines, copyright issues, gcc and g++ compile options and so on, which are adding to the learning curve of every new Haiku developer, I guess ;)

Q3: What would you love to have that would make working on Haiku easier?

An IDE with source code navigation and refactoring support as I know it from the Eclipse IDE. Currently the QT Creator IDE looks pretty promising, which works under Haiku thanks to the QT port :). Now I only need to find out how to set QT Creator up to prevent reindexing the complete Haiku source code every time I freshly start it.

Q4: What interesting book, band, TV show etc. would you like to recommend?

As a developer I love the book "Design Patterns" by Erich Gamma et. al., which helped me to understand the OO world of C++ and I love the design ideas presented in there. Especially the Strategy Pattern, which I like to use when speed is a concern as it was in my bachelor thesis.

As a sportsman in martial arts, the book "Tao Te King" by Laotse provided me insights in the nature of fighting. In an essence it taught me that there is only one matter that I really can influence: my attitude.

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