I'm interested in computers and history, so not surprisingly data processing (precursor to the term IT) history is a particular interest. I'm mainly interested in mainframe and minicomputer history with a slight interest in microcomputer history. More specifically, I'm interested in the IBM System/360 and System/370 mainframes and DEC minicomputers such as the PDP-11 and VAX, but I'm also interested in some early IBM minicomputers like the System/3 and its successors.
The age, size, price, as well as the power and cooling requirements of the aforementioned systems make it nearly impossible for people to use these computers anymore. Fortunately, the dedicated work of hundreds of individuals make this possible on PCs. The Hercules emulator emulates System/370, System/390, and zSeries/System z mainframes. The SIMH emulator emulates many influential minicomputers, including the PDP-11 and VAX, as well as a few microcomputers. I'm an active member of the Hercules community and I've tried to help new users, find bugs, and contribute a little code.
The sheer number of operating systems running on the computers above make it nearly impossible to learn them all well so I've tried to focus on a few. On Hercules I use the public domain MVS 3.8 operating system, a precursor to the more modern z/OS. I've dabbled a little with VM/370 and even less with DOS/360. On the minicomputer side, I'm mainly trying to become more proficient with OpenVMS. Minicomputers have many more Unix-like operating systems available so there is much less learning involved coming from a Linux background.
Since the size and price of workstations and servers have come down greatly, it's possible to own a few. I own an IBM RS/6000 7043-240 which I run AIX on as well as a DEC Alphastation 200 4/166 which I hope to run OpenVMS on soon. While operating systems like BSD and Linux distributions are widely available for these platforms, I believe that the system is a waste if its not running a native or unique operating system, after all, you don't need an RS/6000 to run Linux.
More modern(ish) interests of mine include virtualization and emulation. I use Hercules to do occassional Linux on S/390/zSeries/z9 testing and VMware Workstation on the desktop for trying out a variety of x86 operating systems. I have a few spare x86 boxes lying around for operating systems which don't run on VMware, notably OS/2.
I have a personal web page/blog at http://www.timpinkawa.net which generally deals with mainframe and minicomputer emulation as well as some general computer topics.