RAID - Redundant Arrays of Inexpensive Disks

I was talking with my brother Andy this morning about the wisdom of buying aBlue-Ray player, which sent my mind off on a tangent about how fast you could stream data from a hard disk drive. Hard drives can read and write data pretty quickly once the data has been located on the disk. However, locating the track where the data is stored can be a very slow process, relatively speaking. I just looked up a Western Digital disk that has a average seek time of 7 milliseconds, which is an eternity in a computer. However, track-to-track seek time is only 0.7 milliseconds. Still slow, but considerably faster. However, if you had a bunch of disks all lined up and you could switch between them, you could read (or write) from them successively. While you are reading a track from one, which should only take 10 microseconds for a 10,000 RPM disk, all the rest of the disks would be in the process of moving their read/write heads to the next track (seeking). Dividing the 0.7 millisecond seek time by 10 microseconds gives you 70, which means you would need 70 disks to be able to maintain the maximum data transfer rate for this particular model of disk. 70 disks times 500 gigabytes is 35 terabytes. Given the posted data transfer rate of 3 GB/second, it would take 12,000 seconds, or 200 minutes, or 3.3 hours to transfer all of the data that these disks could hold. That's ten terabytes per hour.

What you would do with all that data is another issue.

Blogger Posting

I just discovered that the number of posts per page was still set to 105. I set it to 105 to facilitate creating a backup copy of my blog before I left. I THOUGHT I had reset it to seven, but either I failed, or Google failed to record it. Anyway, it should be set to seven now so it should not take forever and a day to load.

Midwest Tour

I have had several surprising experiences lately and I have not figured out how to write about them without offending someone.

Right now I am hanging out in Fort Madison and reading "The Confusion" by Neal Stephenson, a really excellent book. I am enjoying it immensely.

I am using Andy's laptop to write this and it is sitting flat on a table which makes it difficult for me to type, so this is the end of this post.

Octopus

Ross sent me a link to a slide show of Paul Allen's yacht "Octopus". The first slide is kind of garbled, but the rest are good. Paul Allen is (was?) one of Bill Gates' sidekicks at Microsoft and owner of the Trailblazers, the Portland NBA team.

I imagine that the only way to top this would be to get it featured in a James Bond movie.

ftp - File Transfer Protocol

A few weeks ago I ran into a situation where I needed to use ftp to upload a file to the internet. Poking around I came across one site that sounded promising but turned out to be worse than useless. I was going to tell them what I thought, but you have to sign up. Yeah, that's just what I want a membership with a really stupid web site. Dummkopfs.

Their suggestions only work on sites that have implemented the necessary features, which means almost none. For any normal site you will need an ftp client program.

A little more searching turned up gftp & filezilla, both ftp client programs for Linux.

gftp installed, but would not run. That was all the effort it got from me. If it doesn't work the first time, I'm not going to spend any time on it.

Used filezilla instead. It installed and ran fine. They have versions for Windows, Linux & Mac.

"Witch Hunt" by Ian Rankin

"Witch Hunt" by Ian Rankin. I think I probably picked this up in a bargain bin somewhere, sometime, I don't remember exactly.

A better than average thriller. There were a few things that bothered me, but they did not crop up often enough to make me quit reading. One was the neurotic, petty complaints people had about their co-workers. They may be a fact of life, but I am not interested. I have plenty of my own to deal with.

Another is when the head of the department flys to Germany to rein in an over zealous agent. I don't think it would have happened that way. The agent would no doubt be called on the carpet on his return, but I don't think the boss would have made a public show of it. Better to keep things like that in the family, so to speak. Going to pick up the wayward soul would only serve to advertise the loss of control. Better to pretend it was all part of the plan in the first place. This section might have made a good dramatic section in a movie version, and maybe that was what the writer was angling for. On the other hand, it did not ring true, and I doubt it would ring true in the movie. But hey, it's a thriller, not an intellectual exercise, so what can you expect?

There was another incident that struck me as false, but I cannot remember it right off. Of course, the whole thing was based on a wacko premise to begin with, but it made a good story.

Wood Cutting

Jack, John & I went shooting out in the woods yesterday afternoon. After blasting away at some close range tin cans, we took aim at a slightly more distant target: an empty quart can about 100 to 150 feet away. John impaled it on a branch so it wouldn't move, even when hit. We had been shooting at it for a while when we noticed that the log the can was attached to had broken. We went to investigate this miraculous happening and found several perforations in the log along with one bullet that hadn't quite made it all the way through. You can see the little circle of metal poking through the wood in the middle right of the last picture.

Google Spell Checker

I try and use a spell checker whenever I write something. Long, complicated words, especially those with double letters sometimes trip me up. And words that sound like they use one vowel and are spelled with another, like separate. My dyslexic typing also generates some errors.

Recently I have noticed that the Google spell checker is high lighting some longish words that are spelled correctly. Now why would they do that? I already have a number of long standing disagreements with their spell checker over things like my name, the name of city where I live, and capitalization of the word "internet". (Google thinks it should be capitalized, I cannot think of one good reason for doing so.)

I wonder if this post will find it's way to Google's world headquarters.

Elevator Puzzle

A classic problem (or so I'm told) from Computer Science. Not too hard to figure out, bit more of a trick to come up with a computer program to figure it out.

A building has 8 floors. It has some number of elevators. Each elevator can stop at any four floors, but only four. We want to be able to take an elevator directly from any floor to any other floor. If we had one elevator that stopped at all 8 floors, the problem would be solved. But due to some outside influence (politics, the elevator operators union, insurance, royal decree, what have you), our elevators can only stop at 4 floors. So we could have 2 elevators: one that stops at the first four floors, and a second that services the top four floors (5 thru 8). All of the floors would have access to an elevator, but the people on the top four floors would be stuck on those four floors and would never be able to leave the building. Likewise the people on the bottom four floors would never be able to get to the top four floors. It would be like two different worlds.

So now maybe you understand the problem. What we want is the minimum number of elevators that would allow you to go directly from any floor to any other floor on one elevator. We don't want to have to change elevators in mid-journey. And no, you can't use the stairs. That's cheating.

Quote of the Day

"While these events took place and portentous lumpiness formed, the Northern Island and the Northeastern Cape stood almost alone, the only two elements that existed in the universe to any significant extent." - from The Periodic Kingdom by P.W. Atkins.

Portentous lumpiness?!?! What a phrase!

Quote of the Day

'The tie between evolution and qualities like complexity and purpose "is murky at best, but it is real and it is worth meditating on" - an unconvincing remark that sounds like a congressman forming a commission when he knows better that to take real action.'

Jeremy McCarter quoting Jerry A. Coyne, in the article "Rage Against The Art Gene" from the April 6, 2009 issue of Newsweek Magazine.

Quote of the Day

Lisa Lundquist (about the movie industry):

"I'm in a funny business, Ray. Everybody talks like hippies and acts like they're in the Sicilian mob."

Lauren Graham plays Lisa on the "Showtime" episode of "Law & Order" (1997).

Mystery Bits

Jack found these bits in a drawer in his garage. Neither one of us can figure out what they are. They are about an eighth of an inch long and about 1/16" in diameter. The cone shape appears to be rusty metal, while the "head" end appears to be a darker metal.

They look like they could be little tiny feet for something. You pound the pointy end into a block of wood, and you have a round metal foot keeping the block a hair off the floor.

Or maybe they work the other way, and the head end is clamped in something so that the point protrudes.

Or maybe they are ... oh, I give up! Does anybody have any idea what they could be?

Update January 2017 replaced missing picture.

Dyanmic Two Dimensional Arrays in C

In computer programming, a list of numbers can be stored in an array. The size of the array can be decided in advance when you write the program, or you can create the array at run time to be any size you want. A simple list is called a one dimensional array.

A two dimensional array is more like a spreadsheet. You have rows and columns. The C programming language supports two dimensional arrays that are created when you write the program, but it does not support dynamic creation of two dimensional arrays.

However, a two dimensional array can be viewed as a list of lists, and because C treats pointers and arrays pretty much interchangeably, it is possible to dynamically create a data structure that functions as a two dimensional array. The computation of the actual address in memory of the data field being accessed may not be as elegant as that done for static two dimensional arrays, but it may be faster as it only involves addition and no multiplication. There is some overhead in storage for an extra row of pointers, but that should not be a problem for today's computers.

I did this once before, but the code wandered off. I am playing with matrices these days, so I decided to redo it. It is not particularly complicated, but you do need to get the details right to make it work. I put the essentials in a demo program you can examine should you be so inclined.

Rammstein - Amerika

Update January 2017 replaced missing video.

Creme De La Creme

Stu Savory had a post about NEETs (No Education, Employment or Training), a British term for those on the dole. I sent him this note:

I wonder about this whole thing. We automate factories so fewer workers can produce more goods. Businesses want more H1-B Visas so they can hire engineers from India and China. The rich get richer and the poor stay poor. One in a million may win a lottery of some sort (an actual lottery, or become a sports or movie star, or a business mogul). One in a hundred may land a "good" job, one that pays enough to buy a house, a car, health insurance and send your kids to college. What about the rest? They're screwed. Why even try, you just get kicked in the teeth by those on top who are only really interested in maintaining their position.

"Get a job" sounds good, but what if there aren't any jobs? And what about jobs that just slowly strangle you? They don't pay enough to pay for your living expenses, much less any savings. What's the point?

Something is seriously wrong with Western civilization, but I am not sure what it is.

I am all in favor of public works projects to put people to work. I think what we need is a grand construction project, like building a pyramid. Maybe that's why the pharoahs built the pyramids: they needed something to keep the unemployed masses occupied.

Going For Groceries

I'm gonna take the car and pick up a few things at the store.

Update January 2017 replaced missing picture.

Too Delicate For Its' Own Good

As I recall, my Mom, ever the bargain hunter, picked up a set of four of these wine glasses at Goodwill. They eventually came to me. Two of them broke through accident and now we are down to two. The last one broke when I bumped it while it was sitting on this table and it fell over. It didn't fall off the table, it simply fell over on the table and when it hit, it shattered.

They are nice glasses, thin, with a nice ring to them, but criminently, they are too delicate to survive in my hands.

Update January 2017 replaced missing picture.

"Decoding the Heavens" by Jo Marchant

"Decoding the Heavens" by Jo Marchant, the story of the Antikythera mechanism. This book is amazing on a number of different levels. Unfortunately, the writing style is not one of them. It seems to follow the breathless potboiler model of some of the mass market stuff like "The DaVinci Code". (Did I mention how much I hated that book? Oh, I did? Sorry, but I really didn't like it. Good story, terrible writing. What is happening in the publishing industry? Don't ask if you don't want to know.)

Anyway, the story is stupendous, the level of science and technology involved in this tale is tremendous. It's like a short course in the development of technology during the 20th century. It also looks at the people and politics involved which gives some insight into academic competition.

It also opens the door to creating a new vision of the city (Atlantis?) that was destroyed by a eruption of a volcano on the of island of Thera in the Eastern Mediterranean around 3500 years ago.

This story seems to be having a hard time gaining traction, and it makes me wonder about people. The stories we have been telling ourselves about the ancient world (anytime before the year zero), all seem to involve massive buildings, massive sculptures and massive armies, but technology was extremely limited. The wheel was like the most sophisticated tool they had. Bronze was used for making swords and shields. Any kind of mechanical technology simply did not exist.

But the Antikythera mechanism changes all that. We have known about the mechanism for over 100 years, but our story about the ancients has not changed one wit. Why is that? Are the historians so wedded to their stories they cannot accept that they might be in error? Or maybe no one cares.

I think this device is very significant and we should be thinking about what it means. Of course, I also like it that it gives some support to my conspiracy theory about the Egyptians and their hieroglyphics.



Update March 2016 replaced missing picture.

Double Cross Blind by Joel N. Ross

Double Cross Blind by Joel N. Ross. An entertaining tail of espionage on the brink of WWII. It reminds me of a line from Thomas Adcock's "Drown All The Dogs":

"It's spies and betrayals and secret codes and treacheries and propaganda and the very thickest of plots and all manner of deception and cruelty required to preserve man's civilization ..."

There are double agents and information that they do not use because if they acted on it, the enemy would know they have a leak, and the leak would be plugged, and then you would get no more information. How do you judge when the information you get is worth enough to justify sacrificing your source? Tough call any day of the week. And even if a particular piece of information is valuable, if you don't use it, you can protect your source so that some day they may provide an even more valuable piece of information. How do you evaluate that situation?

Then there were Tweedle-dum and Tweedle-dee. I have run into these characters in other stories, and they are recognizable and scary. One is big and doesn't say much. The other is smaller and has a sharp mouth, but they are both vicious killers and would as soon gut you as look at you. They are almost caricatures.

A much better book than Zigzag. I am not quite sure what it was that made it better. Fewer obvious flaws, perhaps? The hero did seem to suffer more than was reasonable, and seemed to perform better than he ought in fights, given his condition, but sometimes that's what makes the story.

I kept thinking about Dan Brown's "The DaVinci Code", which had a number of similarities, but was a really terrible book. I hated it. It made a pretty good movie, but the book was just awful. Without going back and analyzing their writing, I can't say what makes "Double Blind Cross" so much better than "The DaVinci Code", but it most certainly is a much better story.

Sign of the times

Update January 2017 replaced missing picture.

Not Honey

Went to Dove VB to celebrate John's birthday yesterday evening. It's a small, organic-ish pizza joint on East Glisan, which means it's on the other side of the Willamette River. We were downtown anyway to pick up Ross from the train station, so it was a short jaunt to the pizza place. I ordered a glass of ice tea and they brought me something that did not look at all like ice tea. It was totally opaque, like a fruit smoothie or something, but it tasted like tea, VERY strong tea. They also brought me some sugar which I applied liberally. The sugar cut the tea taste down to tolerable, but not enough to make it really sweet. Then another waitress brought me this bottle of Blue Agave Sweetener. It looks like honey, and it tastes like honey, but it pours a little easier. It is not quite as thick. Adding just a dollop to the tea made it really sweet.

The boys got pepperoni, the girls got spinach, and my wife and I ordered a special with ham. It was a little off-putting when it got to the table: it looked positively black, but it smelled good and it tasted fine, with just enough spice to make it interesting.

Update January 2017 replaced missing picture.

Quote of the Day

"No matter what story you try to tell about the twentieth century, in the end you find its course diverted by the Second World War - a great, dark smear on history that sucks in everyone and everything before releasing them, a few years later, on new trajectories." - Decoding the Heavens by Jo Marchant.

Sign of the times

This sign is posted in a parking lot in downtown Hillsboro that is convenient to the farmer's market that is held on Saturdays. One week we went to the market and parked in this lot and we both interpreted the sign to mean that we could park at the spaces without meters. We went again the next Saturday and saw the same sign and interpreted it to mean we could only park where there was a parking meter. Are we slipping, or is this sign confusing? Or did they change the sign from one week to the next?

Update January 2017 replaced missing picture.