The best kept secret of system administrators is that we get to play with the most powerful computers in the world. Not only that, we get paid, too! So, you ask, if work is so much fun, what do sysadmins do when they are not at work?

Well, actually, most of us are on-call, 24 hours a day, 7 days a week, 365 days a year, but we do other things on those rare moments away from our keyboards: extreme sports (mine is bicycling); reading books that are not software manuals (usually science fiction or mysteries); and artistic or intricate handcrafts (mine are building full-sized aircraft, quilting, and, most recently, weaving).

The latter, weaving, is my latest affliction. Most of our hobbies have some relationship with the primary activity, computer programming and computer maintenance, and mine are no exception. Assembling a quilt is like executing a computer program, with subroutines and loops to cut patches, assemble them into blocks, blocks into strips, and strips into a quilt. I’ve dabbled in loomwork beading, where the beads are arranged in a grid like pixels on a computer display, to form a picture or pattern. And now, fabric weaving, which reminds me of the old days when computer backplanes were a grid of closely-spaced circuit-card pins, interconnected with tens of thousands of tiny wires. The backplanes were initially wired by robotic machines, but what we now call firmware changes had to be hand-wired, using fine crochet hooks and drill-like wire-wrapping tools to remove the old wires and weave new ones into the mat.

Dressing a loom (threading the warp threads through the heddles and reed) is much like modifying the old wire-wrap backplanes.  In the photo above, the thread tied on the front of the reed is the half-way mark.  The warp threads on the left are grouped next to the heddles through which they will be threaded.

The above photo is the back of the loom, showing the warp threads wrapped on the warp beam and spaced through the raddle, which will be removed after the warp is threaded and tied to the cloth beam in front.  There are 342 threads in this warp, each of which must be threaded through a heddle and a reed slot in a particular order.  The heddles, on four shafts, are raised and lowered by six foot treadles, each of which is tied to one to three shafts, according to the design.  The treadles are pressed in a specific order to create the weaving pattern.

So far, this has been a relaxing diversion from the keyboard, and brought back memories of, well, working on memories (of the computer kind).  The piece to be woven is a mix of synthetic viscose fibers and wool, so the result may or may not be successful, depending on the shrinkage rates of the two fibers.

Stay tuned.  Meanwhile, back to the more abstract concepts of kernel tuning and performance analysis of parallel and threaded (the execution flow kind) software.