A couple of posts ago, I mentioned Steve Green’s quest for science fiction recommendations. One of the comments had a link to the CDs that Baen Books has been including in some of the books they publish. I’ve bought two or three of the books that contain these, but it’s nice to see so many of them in one place.
Want to do some reading?
February 22nd, 2010The files are out there
February 22nd, 2010You think you’ve got snow?
February 22nd, 2010You don’t have snow.
We’ve been having snow here in the Denver area for the last couple days, but nothing like that shown in those photos. I’ve seen snow that matches the photos of the “roads with walls” before – I’ve driven on roads like that in rural Idaho in the late 1970s, and parts of Rabbit Ears Pass look like that almost every time I drive that way.
Quote of the Day
February 21st, 2010Steve Green has a post up requesting advice on science fiction to read. He’s received a number of good suggestions, many of which I’ve read. I was particularly taken by a recommendation for H. Beam Piper, who is one of my favorite authors. That comment included a link to his author section on Project Gutenberg, and, in particular, Rebel Raider, from which comes the following. I thought the quote was particularly timely. I could have limited it to just the last sentence, but I felt the context was worth it.
In this last, his best selling-point was a recent act of the Confederate States Congress called the Scott Partisan Ranger Law. This piece of legislation was, in effect, an extension of the principles of prize law and privateering to land warfare. It authorized the formation of independent cavalry companies, to be considered part of the armed forces of the Confederacy, their members to serve without pay and mount themselves, in return for which they were to be entitled to keep any spoil of war captured from the enemy. The terms “enemy” and “spoil of war” were defined so liberally as to cover almost anything not the property of the government or citizens of the Confederacy. There were provisions, also, entitling partisan companies to draw on the Confederate government for arms and ammunition and permitting them to turn in and receive payment for any spoil which they did not wish to keep for themselves.
The law had met with considerable opposition from the Confederate military authorities, who claimed that it would attract men and horses away from the regular service and into ineffective freebooting. There is no doubt that a number of independent companies organized under the Scott Law accomplished nothing of military value. Some degenerated into mere bandit gangs, full of deserters from both sides, and terrible only to the unfortunate Confederate citizens living within their range of operations. On the other hand, as Mosby was to demonstrate, a properly employed partisan company could be of considerable use.
It was the provision about booty, however, which appealed to Mosby. As he intended operating in the Union rear, where the richest plunder could be found, he hoped that the prospect would attract numerous recruits. The countryside contained many men capable of bearing arms who had remained at home to look after their farms but who would be more than willing to ride with him now and then in hope of securing a new horse for farm work, or some needed harness, or food and blankets for their families. The regular Mosby Men called them the “Conglomerates,” and Mosby himself once said that they resembled the Democrat party, being “held together only by the cohesive power of public plunder.”
Note: I updated the post to make it clearer that Rebel Raider is history, not fiction. Piper was a history buff – in the introduction to one of his books (a collection of short stories, I believe, although it’s not handy for me to check), Jerry Pournelle states that Piper knew both the grand sweep of history, as well as many of the obscure stories.
This looks like fun
February 17th, 2010What you see may not be what you get
February 17th, 2010There’s an interesting post here about heisenbugs and compiler optimizers. I’ve found two compiler bugs in my time. One was related to the optimizer, although it wasn’t due to the compiler generating incorrect code. Well, not quite, anyway.
In one case, a commercial embedded cross-compiler, the optimized code the compiler was generating was logically correct code. The problem was that it was incorrect in context. I was accessing machine registers that had to be accessed with 16-bit operations – if you tried to access half of the register with a byte operation, the processor would overwrite the other half of the register with random data. Naturally, the compiler was optimizing 16-bit accesses that only dealt with one byte of the register to 8-bit operations, because that was the better thing to do when dealing with normal memory. The compiler could produce code for several related variants of the processor in question, and I’m not sure that the register restrictions in question applied to other processors at the time.
I reported what was happening to the vendor, and they changed it in the next release of the compiler, but I couldn’t wait for the fix, and had to use assembly language to produce my access routines.
The other instance involved an IDE that used GCC as a cross-compiler. Our code wasn’t working, and initial investigation showed results that made no sense – one passed parameter was getting the value meant for the other, and another was getting a garbage value. Closer examination of the generated code showed that the stack frame for the function call in question was being built incorrectly, which beggared belief. Why was it only happening on this one call, rather than on all of them? If it were a general bug, there would be virtually no programs would be compiled correctly – what was it about this one call? Further investigation showed that the vendor had grabbed a version of GCC that had been pulled from distribution after about a day because of a significant bug involving calling across languages – calling C routines from C worked, as did calling C++ routines from C++, but calling one from the other didn’t … the specific bug that we were seeing, although we didn’t realize that it was due to a cross-language call until we saw the release notes on the GNU website. We were lucky that the vendor provided the capability to tell the IDE how to access other tools, or we’d have been dead in the water on our project.
It’s not often that you run into compiler bugs, unless you’re the one maintaining the compiler (in which case you probably see them more often than you’d care to). Most times, the problem is in your code, not the compiler. However, you can’t rule it out, particularly if you’re doing things that stress the compiler’s capabilities, or use features that most people don’t require. Some people make a point of looking for compiler bugs, which is nice of them. It’s not what I’d care to do on a daily basis, although I have designed and written test code to verify that language features work as intended.
One of those timeless messages
February 6th, 2010
A Message to Garcia is a standard topic in leadership courses, at least in the ones I attended back in the 1970s. Lt. Rowan is held up as someone to emulate, although the assistance he received sometimes left him with so little control over his situation that he was concerned about where he was being taken.
I’d never read Rowan’s description of his trip, so that was interesting, and re-reading Hubbard’s essay was also interesting – I picked up on his examples about grammar and punctuation this time, partly because I had just read an essay on that topic, and partly because I’ve written about that particular topic myself.
I think it’s great, but it’s not my style
February 6th, 2010I’ve known people who could and would, and I have no doubt that Cdr. Salamander is one, but Akbar Zeb is not a name I’d be comfortable using.
I find myself reminded of a Goon Show episode
February 6th, 2010In one episode, the Goon Show told their version of the Robin Hood story. After he won the archery competition while competing in disguise, the following dialogue occurs:
“You pull a mean bow, archer.”
“Yes, it was given me by a mean uncle.”
“No, really, where did you learn to pull a longbow?”
“I took a postal correspondence course. The envelopes were six feet long.”
What brought this to mind was reading about a man who once mailed a building.
Spaced out
January 31st, 2010Not quite the witty title I wanted, but it fits the theme.
I missed this story when it came out, but it’s newsworthy because it’s a very low-probability event: a 14-year-old boy was struck by a meteorite last year.
Next, we have a claim that space aliens may not be friendly. Is this news to anyone? Besides peace-and-love-and-crystal-harmony types, that is? It’s not like there haven’t been books and movies addressing the topic before. Given the history of war between different tribes and nations, why would anyone presume that aliens would necessarily be peaceful?
One quote from the article is worth a little discussion:
Some scientists are puzzled as to why no messages have been sent back even though humans have been transmitting radio and television signals for the last century.
That’s actually a pretty stupid thing to be puzzled about. First, that would require another intelligence within 50 light years, and further presumptions that:
- They received the broadcasts and recognized them as a product of intelligence immediately.
- They deciphered them immediately.
- They decided to send a response immediately.
- They had the equipment available immediately for sending that response.
Just coming up with some simple points for each of the above:
- When the first pulsar was detected, some thought it to be a broadcast from an extraterrestrial intelligence, because it was considered too regular to have been natural.
- How long have we been working on Linear A? Would we ever have deciphered Egyptian hieroglyphics without the Rosetta Stone?
- Let’s hope they’re not organized with bureaucracies. Perhaps they’re afraid we (or someone else) would find them and hurt them. Maybe they’re isolationists.
If they’ve got equipment to receive us, they’ve probably got equipment to send back, so that’s not necessarily a big objection. They may have reasons for not wanting to use it, or to broadcast at the necessary level to reach us. Then again, perhaps they have already responded to us, and we didn’t recognize it as a response, because it’s using a technology that they expected us to develop in the meantime.
It’s probably moot, though. A few months ago, I read an article that said that our broadcasts would sink into the background noise within some distance that I don’t remember, but was shorter than I expected. I couldn’t find a link to it to put in this post, but I did find this, which makes the same point. We do have equipment that can pull signals out of the noise, even if the noise is louder than the signals, but in that case, we know what kind of signals we’re looking for. That’s a lot different than, “There may be a signal here. It may be hidden below the level of the noise, and we have no idea what it looks like.” Searching for it in those conditions is a good recipe for ongoing employment, but not necessarily for success.
It may be moot for another reason, though. Technology marches on, and the changes and improvements have side effects. When I was younger, I used to see billboards across the southwest for radio station XERF, broadcasting from just across the border in Mexico with 250,000 watts of broadcast power. They were in Mexico because, among other reasons, it freed them from FCC restrictions on broadcast power. My understanding was that atmospheric skip meant that they could be heard across most of the US, at least at night. Recently, I’ve been hearing about low-power FM and neighborhood radio. Lower-power signals means a shorter propagation distance before it falls into the background noise.
In the early days of personal computing, back in the 1970s, I read about how some people were using AM radios to debug their programs: the switching frequencies of the digital signals in the computer fell into the AM range, so tuning between stations would let you hear a series of shifting tones that related to what the application was doing. In the days when some people only had lights and switches for I/O, that could be an important diagnostic technique. Nowadays, computers operate well above the AM range. They take less power (sometimes absolutely, sometimes merely relatively) than they used to, as well. I work in the field of embedded computing; Intel’s 80188 processor, which used to be popular for the purpose, consumed 800 milliamps if you were using the NMOS part. The MSP430 from Texas Instruments can require as little as a couple microamps. That’s not going to generate much in the way of radio signal.
So, I guess what I’m saying here is that it’s pretty unlikely that aliens shot the rock at the kid.