Monday, July 4, 2016

Bit-twiddling...

Bit-twiddling...  I used to have quite a bit of fun with things like this in assembly language.  The need doesn't arise very often these days, especially in the later versions of the Java language where many twiddling primitives have been added.

Reading through the linked bit-twiddles brought back a memory, from 1981 when I worked for a company called Xscribe.  They made an electronic stenographic machine (the StenoRam 3), shown at right.  This was a battery-powered device, and back then there was really only one choice if you wanted a low-power microprocessor: the RCA 1802.  This chip's claim to fame wasn't processing power :)  The 22 key switches on that thing were read on input bits, and they needed to be debounced and decoded in firmware.  Any combination of keystrokes was potentially valid, which added to the complexity.  The firmware that did this work involved a lot of bit-twiddling, and because the processor was so slow, the performance was critical.  I remember spending days agonizing over four or five lines of code, trying to squeeze a few cycles here and there.  Lots of challenging, puzzle-solving fun!

Shooting with mom...

Shooting with mom...  On one of my visits to my parents, in the '90s, they were living in a small apartment while they waited for their new home to be built.  This apartment was located on a lot adjacent to the lot their house was being built on, which was very convenient for them.

Mom owned a .357 revolver, which she had purchased for her own protection.  This was a gun she kept in their house, not on her person.  At the time of my visit, she'd only been to a firing range twice to practice with the revolver, and she wanted to be more familiar and comfortable with it.  She knew that Debbie and I owned firearms, so she asked me if I'd take her to the range for some practice.  She had about 100 rounds she'd already purchased, magnum loads For those readers not familiar with firearms, “magnum” is a marketing term that generally means the round has more gunpowder or a heavier bullet than the “normal” rounds of the same caliber.  In mom's case, it meant a slightly longer round with more gunpowder.  She had never practiced with magnum rounds before, and she knew they would make the revolver “kick” more, so she wanted to practice with that.

When we got to the range, we were the only ones there.  Because of that, we didn't even need a range master (the guy in charge of telling people when it was clear to fire, when to cease firing, etc.).  It was just the two of us on a big range with about 40 firing positions.  We set up a target at 25 feet.  If you're not familiar with shooting handguns, that may seem close – but it's actually a fairly long range for such a short gun.  For self defense, the actual range is generally quite a bit shorter than that.  So if you can shoot reasonably well at 25', you're in good shape for close-in self-defense use.

Mom was all business with that revolver.  She didn't “shoot like a girl” at all.  She had been worried about the added kick of a magnum round, but it turned out to be a complete non-issue for her.  She still had very strong arms and hands back then.  Each time she fired, she had the sights back on target within a couple seconds, most of the time under one second.  That's not bad at all!  After about 50 rounds, she was getting 4" groups (in other words, her bullets were all hitting within a 4" diameter circle drawn around the bulls eye), which is more than good enough for self defense.  For the last 50 rounds, I did my level best to distract her (trying to simulate the chaos of an actual event where she needed to use the gun), and I failed miserably – she was just as accurate when I was screaming at her as when I wasn't.

Each time when she was reloading, she told me about the fantasies she was having as she aimed her gun at the target.  She had a list of imaginary targets that she'd like to put a bullet into.  Her list was comprised entirely of politicians, a class of people she generally thought of as dishonest, corrupt, lying thieves.  The major difference between them, in her mind, was a matter of degree and whether they'd been caught.  Bill Clinton, in particular, disgusted her; for him she reserved a special contempt and a special desire that he meet a painful, punishing end.

When we were done practicing (I shot a few rounds myself, mom the rest of them), she wanted to clean the weapon right then and there at the range.  I prevailed upon her to wait until we got home, where I watched her do one of the most thorough cleanings of a revolver I'd ever seen.  She must have used 30 cotton patches in the process!  I also ran her through a bit of safety drill on the revolver, to make sure she knew how to “safe” the gun in a way that would make law enforcement comfortable, and also that she knew how to reload in a hurry.  She didn't know about speed loaders, so I went with her to a nearby gun store to buy some.

Mom's attitude toward guns (including the possible need to use one) was very pragmatic, and unsurprising to me.  It was of a piece with her no-nonsense, no-bullshit character.  If a bad guy was threatening her or her family, putting a few bullets in him would seem to her like the obvious and sensible thing to do.  If that meant the bad guy was killed or crippled, that's not something she'd be losing any sleep over.  To her, that gun was just a convenient “power” tool – she'd have been just as comfortable with a knife or a pitchfork used for self defense.  But the gun was a better tool for the purpose, so to her it was clear that she needed to have one, and how to use it.  So she did.

My dad, on the other hand, didn't like being around guns at all.  He made it clear that the revolver was entirely mom's affair, and he good-naturedly refused to have anything at all to do with it.  I once tried to get him to talk about the reasons why he had that reaction to guns, and all he would say to me was that after his experiences in North Africa, he wanted to stay as far away from guns as possible.  Dad wasn't in combat in North Africa; he was stationed far behind the lines at a telegraphy site.  But I know from my reading about WWII that many of the Allied casualties (both dead and wounded) were evacuated to the same general area where dad was (in eastern Algeria, and later near Tunis).  The conditions were awful – a shortage of both doctors and medical supplies, and no proper hospitals at all.  This was an early experience in the war for the U.S., and things were terribly disorganized.  Dad quite likely saw some horrible things, and most of those would have been caused by bullets.  But that's all just speculation on my part, based on that one statement – dad never said any more than that on the subject, at least not to me...

Happy Independence Day, fellow U.S. citizens!

Happy Independence Day, fellow U.S. citizens!  For the past few weeks, every time I meet a kid around here I've been asking them if they know why we celebrate on the Fourth of July.  Out of about a dozen kids, only one didn't know the reason, and she was only about 8 years old.  All the rest knew it was Independence Day, and even that it was the day we declared our independence from England.

Something tells me that if I were to make the same (highly unscientific) survey in San Diego, the results would have been much different...

Update, just a few minutes later: reader, friend, former colleague, and Idaho mogul-of-everything Doug S. sent me this video.  It was made in San Diego, and it shows that my intuition above was ... totally correct.

Thanks, Doug.  I think...