Inflation and the slide rule
Apr. 27th, 2013 09:05 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
altivoNo, I'm not talking about pool toys here.
This week I spent $13 to buy an old Versalog slide rule off EBay. I've wanted one for years, in fact since they were actually still being made. That would be around 1969 or 1970, when I was still in college. (For any readers too young to remember what a slide rule is, it's a mechanical calculating tool that works on logarithms. The slide rule was used by engineers and scientists through much of the 19th and 20th century and many of our architectural monuments and mechanical achievements were based on slide rule estimates and calculations. This includes early space flight experiments as well as things like the Empire State building and the Golden Gate bridge. Though it looks crude in comparison to a modern digital computer, the slide rule is still a useful tool. Unfortunately they aren't made any more (other than as novelty items perhaps) and no one learns to use them.
Anyway, the Versalog I acquired still has the leather protective case with the name of a former owner inscribed under the flap. The rule was very dirty, but it cleaned up well and I realigned the scales and cursor so it is usable. Then some historic research. This rule was made in April of 1962, so it is 51 years old this month. It sold new for about $29.95, which was a lot of money back then. Versalog was the "Cadillac" of slide rules according to most of the guys in my undergraduate classes. In fact it is a very good tool, well made and precise, and built to last with very little maintenance.
After a discussion with Gary about the equivalence of that $29.95 price in modern dollars, I went to an online calculator to figure the actual inflation rate. It turns out that $30 in 1962 had the same purchasing power as $231 today. Now I understand much better why my dad was so protective of his "good" slide rule that he kept in his work brief case and wouldn't let me or my brothers touch, let alone use.
Today that $231 is enough to buy groceries for Gary and myself, plus the food for our two dogs and three horses, for about two weeks. Because the inflation calculator is based on the Consumer Product Index, I assume the $30 in 1962 would have gone about as far. A professional grade slide rule was a substantial purchase back then, much more than a pocket calculator, even a scientific one, is today. In fact, you can buy a low end tablet computer for $200 now.
I do intend to use the Versalog for radio and electronics type calculations. I'll be treating it with a great deal more respect in light of this new awareness. It is a pleasant tool to handle, with a nice heft to it. The slide and cursor operate smoothly now that it has been cleaned, It is more than sufficiently accurate for analog electronics. In fact, we used slide rules in my college physics and astronomy classes to calculate much more complex equations. I could use a calculator of course, or a computer, but I like the connection to historic principles and the awareness of mathematical concepts that a slide rule engenders. And... no batteries required. No charger, no solar panel, nothing but a steady hand and a sharp eye.
This week I spent $13 to buy an old Versalog slide rule off EBay. I've wanted one for years, in fact since they were actually still being made. That would be around 1969 or 1970, when I was still in college. (For any readers too young to remember what a slide rule is, it's a mechanical calculating tool that works on logarithms. The slide rule was used by engineers and scientists through much of the 19th and 20th century and many of our architectural monuments and mechanical achievements were based on slide rule estimates and calculations. This includes early space flight experiments as well as things like the Empire State building and the Golden Gate bridge. Though it looks crude in comparison to a modern digital computer, the slide rule is still a useful tool. Unfortunately they aren't made any more (other than as novelty items perhaps) and no one learns to use them.
Anyway, the Versalog I acquired still has the leather protective case with the name of a former owner inscribed under the flap. The rule was very dirty, but it cleaned up well and I realigned the scales and cursor so it is usable. Then some historic research. This rule was made in April of 1962, so it is 51 years old this month. It sold new for about $29.95, which was a lot of money back then. Versalog was the "Cadillac" of slide rules according to most of the guys in my undergraduate classes. In fact it is a very good tool, well made and precise, and built to last with very little maintenance.
After a discussion with Gary about the equivalence of that $29.95 price in modern dollars, I went to an online calculator to figure the actual inflation rate. It turns out that $30 in 1962 had the same purchasing power as $231 today. Now I understand much better why my dad was so protective of his "good" slide rule that he kept in his work brief case and wouldn't let me or my brothers touch, let alone use.
Today that $231 is enough to buy groceries for Gary and myself, plus the food for our two dogs and three horses, for about two weeks. Because the inflation calculator is based on the Consumer Product Index, I assume the $30 in 1962 would have gone about as far. A professional grade slide rule was a substantial purchase back then, much more than a pocket calculator, even a scientific one, is today. In fact, you can buy a low end tablet computer for $200 now.
I do intend to use the Versalog for radio and electronics type calculations. I'll be treating it with a great deal more respect in light of this new awareness. It is a pleasant tool to handle, with a nice heft to it. The slide and cursor operate smoothly now that it has been cleaned, It is more than sufficiently accurate for analog electronics. In fact, we used slide rules in my college physics and astronomy classes to calculate much more complex equations. I could use a calculator of course, or a computer, but I like the connection to historic principles and the awareness of mathematical concepts that a slide rule engenders. And... no batteries required. No charger, no solar panel, nothing but a steady hand and a sharp eye.
no subject
Date: 2013-05-08 08:42 pm (UTC)Heftiest Intel i7 is these days about 1.2 billion transistors. That'll work for a very crude multiplier.
I saw an interesting video somewhere where they showed one byte of radio tube technology. Basically it was the necessary valves for keeping the data in, a mess of components attached, and rails to make them somewhat swappable, whenever something failed. Quick guesstimate for the size, about 20 cm x 20 cm x 5 cm. That is, 0.002 cubic meters.
Multiply something small with something huge, we get 2.4 million cubic meters. Make it a cube... and it's about 134 meters (440 ft) per side.
Turn it into something nice and flat, say ten meters high, then we'll get 240 thousand square meters. To which Wikipedia says that it's about the same size as the largest statesian shopping mall, maybe a bit larger.
This of course assumes that the whole place is nothing but radio tubes, and they somehow magically work without crawlspaces and massive pipes for cooling systems. And I haven't even seen the big malls really, so I've no clue about that. I went to see some local mall thingie in Seattle, and even that seemed pretty huge to me. The place where I live seems so much smaller now... :-)
In the end, I'm pretty happy with my estimate about how wrong I was as well, multiply a medium-sized mall by ten, and maybe it's getting pretty close. :-)
no subject
Date: 2013-05-08 08:58 pm (UTC)I've seen a single flip-flop (one bit) in a museum, made in the 1940s using octal tubes. As I recall, it contained four tubes and occupied about a cubic foot when you allowed for the chassis, framework, and ventilation space required.
The CDC computers we used when I was in college (1967-71) had magnetic core memory, which was a lot smaller but still huge and heavy (and expensive) compared to today's devices. And it still generated a lot of heat that had to be controlled somehow. The wires threaded through those magnetic beads where delicate, about a hair's thickness. Emergency power was needed not to keep the machine running but to keep the cooling fans running if the power went out. Otherwise the memory cores could melt down just from the residual heat. (Or so they told us.)
no subject
Date: 2013-05-09 12:22 am (UTC)I think I saw mentioned somewhere that it had to be hand-built, since it was too difficult to make a machine that could do all the wiring? It definitely looks delicate...
no subject
Date: 2013-05-09 04:01 pm (UTC)