SQLServer and its SQL Native Client are communicating through the protocol layer called SNI (SQLServer Network Interface). The data packet is in MS proprietary format called TDS (Tabular Data Stream),
SQLServer communication supports 4 protocols:
(1) Shared Memory - used within the same server
(2) Named Pipe - developed for LAN environment. Used within the server or between 2 server across LAN.
(3) TCPIP
(4) VIA (Virtual Interface Adapter) - used with compliant hardware
Friday, April 18, 2014
Thursday, April 17, 2014
Piano
Piano is a percussion instrument. Notes are produced by hammer striking the strings with force purposely asserted by the player. The amount of force determine the loudness of the notes. The piano was invented in 1709 in Italy. The full name is call piano-forte which means soft-loud. The instrument predate piano is called harpsichord which produce note by plucking strings instead of hammering like piano. Harpsichord player cannot alter loudness as the plucking distance is constant.
Musical Notes and Noise
Musical notes are sound in repeat pattern. The form may not be smooth sinusoid and rugged. In fact, almost all musical instrument produce note in its unit repeating form (timbre). Noise on the other hand has a form that is not repeating.
When a string is pull and released, it produce the base frequency and multiple of it. For example, an A string on guitar produce a base frequency of 110 Hz, and multiples like 220 Hz, 330 Hz ... etc. If the string is pulled in the middle, the frequencies comprises 110/330/550/770... etc. There will be no even multiples. The reason is the mid point is at the highest position at only the odd multiples will fit. The even multiple will have the mid point in the lowest position. If the pull is at 1/3 position of the string, the frequency bundle will comprise the even multiples.
These multiples are call harmonics. No matter the composition for the A note, the combined wave form will repeat at the base frequency of 110 Hz. That is why all the A sounds alike.
When a string is pull and released, it produce the base frequency and multiple of it. For example, an A string on guitar produce a base frequency of 110 Hz, and multiples like 220 Hz, 330 Hz ... etc. If the string is pulled in the middle, the frequencies comprises 110/330/550/770... etc. There will be no even multiples. The reason is the mid point is at the highest position at only the odd multiples will fit. The even multiple will have the mid point in the lowest position. If the pull is at 1/3 position of the string, the frequency bundle will comprise the even multiples.
These multiples are call harmonics. No matter the composition for the A note, the combined wave form will repeat at the base frequency of 110 Hz. That is why all the A sounds alike.
Sunday, April 13, 2014
Chaos
Chaos is a phenomenon. A chaotic system has a property called nonlinear dynamics which describe the cause and effect are not related in a linear fashion. In other words, a small cause can have a complex effect which is not expected. This is why it is called nonlinear.
Order and determinism can eventually lead to randomness. The randomness was due to unpredictability in the systems.
Order and determinism can eventually lead to randomness. The randomness was due to unpredictability in the systems.
Determining the Future
The French mathematician Pierre-Simon Laplace suggested an intellectual being (demon) that knows the position and motion state of every particle in the Universe, and every forces that acts on them, that being is able to predict the future and make change to it.
While theoretically possible, it cannot be done to do so because it is impossible for anyone to know with absolutely precision of the properties of every interacting atoms.
In 1886, the Sweden King offered a prize of 2500 kroner to anyone that can prove or disprove the stability of the solar systems. In other words, will the planets remain their orbits or one of them may crash into the Sun or drifted out of the system eventually. The French mathematician Henri Pancare tried to analyze the problem with just 3 bodies - the sun, the earth and the moon. Pancare found that even with only 3 objects, the equations are mathematically impossible to resolve because of the sensitivity to the initial conditions. The calculations showed complete irregularity and unpredictable result. Pancare nonetheless won the prize.
There are the billiard game software widely available these days. While it is possible to simulate the interaction of balls on the table, it is impossible to predict in reality. To predict, one must know the position and movement of the white ball. One must also know the position and movement of all other balls, and the friction of every strain of fiber on the table cloths which affect the friction, and the size and shape of every dust on the table that could steer the ball off course for a minute immeasurable amount etc.
Edward Lorenz is a mathematician and meteorologist in America. In early 1960, Lorenz used a LGP-30 desktop computer to run a weather simulations. At one point, he wanted to continue a simulation half way by re-entering intermediate calculated numbers from a print out. Unexpected, the result of the simulation is different from the lat runs. The reason was the computer calculate using 6 decimal points but the printout only contains 3 decimal points. Lorenz noticed that the minute difference can make a big impact to the simulation result. He coined the term butterfly effect to describe the rippling effect which based on the 1952 novel by Ray Bradbury.
While theoretically possible, it cannot be done to do so because it is impossible for anyone to know with absolutely precision of the properties of every interacting atoms.
In 1886, the Sweden King offered a prize of 2500 kroner to anyone that can prove or disprove the stability of the solar systems. In other words, will the planets remain their orbits or one of them may crash into the Sun or drifted out of the system eventually. The French mathematician Henri Pancare tried to analyze the problem with just 3 bodies - the sun, the earth and the moon. Pancare found that even with only 3 objects, the equations are mathematically impossible to resolve because of the sensitivity to the initial conditions. The calculations showed complete irregularity and unpredictable result. Pancare nonetheless won the prize.
There are the billiard game software widely available these days. While it is possible to simulate the interaction of balls on the table, it is impossible to predict in reality. To predict, one must know the position and movement of the white ball. One must also know the position and movement of all other balls, and the friction of every strain of fiber on the table cloths which affect the friction, and the size and shape of every dust on the table that could steer the ball off course for a minute immeasurable amount etc.
Edward Lorenz is a mathematician and meteorologist in America. In early 1960, Lorenz used a LGP-30 desktop computer to run a weather simulations. At one point, he wanted to continue a simulation half way by re-entering intermediate calculated numbers from a print out. Unexpected, the result of the simulation is different from the lat runs. The reason was the computer calculate using 6 decimal points but the printout only contains 3 decimal points. Lorenz noticed that the minute difference can make a big impact to the simulation result. He coined the term butterfly effect to describe the rippling effect which based on the 1952 novel by Ray Bradbury.
Tachyon
It is a type of subatomic particles that predicted by Einstein's mathematics which travel faster than light. The word's root is tachys which means "fast" in Greek.
GPS time correction
The pull of gravity causes clock to run slower than outer space based on relativity theory. Satellites orbiting at 400km altitude still have 90% of gravity pull as on surface and so clock aboard runs slightly faster. At the same time, the satellites are moving fast sideway that prevent them from falling down. This high speed movement slows down the clock.
The reduction of gravitational pull causes the satellite clock to run faster than Earth by 45 micorsecond a day. The movement of the satellites on the other hands slow down their clock by about 7 msec a day. This gives a net effect of 38msec a day slower for clock in satellites.
GPS positioning works by measuring the time it takes for a signal from the device on the ground to bounce off a satellite and returns. As each msec delay is translate to about 300 meters. The time difference, if not correct, will cause positioning problem of 10km each day.
Subscribe to:
Posts (Atom)