DAY 1
Listen to the introduction of the teacher Alex Li, the application of Python in well-known companies, the fields that Python is good at, the future prospects and current income, the prospects of the Go language, the entry salary of Python, the offer sharing of the veteran students, and the course rewards
DAY2：
History of Computers:
Finger counting, counting chips, abacus,
In 1630, the British mathematician Outlet invented the scale, the appearance of the scale, the prototype of the vernier caliper;
At the end of the 18th century, Watt added a slider to store intermediate results, which became popular after 1850 until 1960;
Pascal was born in 1623, and in 1642 Pascal invented the first mechanical computer at the age of 19
Pascal died in 1662. Leibniz, a great German mathematician, saw Pascal's paper on the addition computer, and finally produced a more perfect mechanical computer in 1674, which could continuously add and subtract. Continuous addition is multiplication and continuous subtraction. It is division, and modern computers are still affected by these mechanical logics;
In 1725, the "perforated paper tape" of the textile machinist cloth bridge appeared in the textile industry. Through the perforated paper tape, the textile machine realized the function of automatically executing the pattern preparation, which was the prototype of the "program".
In the 18th century, France initiated a project of HTC-manual compilation of "mathematical tables", but there were too many manual errors. Babbage spent 10 years to invent the "differential table" from the concept of the textile machine in 1822. "machine", which can process 3 different 5-digit numbers with 6-digit precision, so the government wants to build a larger difference engine. Since the project could not be completed, it was unsuccessful in the end. In 1842, the government stopped all funding for him. At this time, he received a letter from Ada Augusta, the daughter of the great British poet Byron, expressing his support for him. Ten years ago, she had Listen to Babbage explain the principle of the difference engine. In 1834, Babbage invented the "analytical engine", which has a "repository", "operation room", "feeding parts", "removing parts", etc., which is almost the original version of modern computers, and Ada is also for this. The equipment has produced a lot of programs, and is well-deserved as the world's first programmer.
In 1890, Dr. Hollerith, a German expatriate, conducted a census in the United States. The previous census took 7 years manually, and the changes during the period made the data extremely inaccurate. According to Babbage's invention and Jaccard's perforation, Dr. Paper tape, it only took 6 weeks to count accurate data. In 1896, Dr. Hollerith founded the predecessor of IBM. So far, the computer is still in the mechanical age.
In 1906, DeForest in the United States invented the electronic tube, which laid the foundation for the development of computers; in 1907, he invented the vacuum triode, which can represent the two states of "saturation" and "cut-off", and the control speed is faster than Aiken. The relays are countless times faster.
In 1924, IBM was established.
In 1936, when the young American Howard Aiken was studying for a doctorate in physics at Harvard University, he needed a machine to replace him because of the need for a large number of calculations of calculus and nonlinear equations. Three years later, Aiken discovered that Babbage and Ada’s thesis, after graduating from Ph.D., Aiken found a teacher who worked in the “Columbia University Statistics Bureau” invested and founded by IBM, and asked for a letter of recommendation to IBM Chairman Watson, bringing his own The feasibility report of , received an investment of 1 million US dollars and started the development of "MARK 1":
MARK 1 is composed of about 3000 relays, which are operated with the help of current. On means 1 and off means 0. The relay can make or break the circuit in about 1/100 of a second. Once, the woman who wrote the program for Mark 1. Mathematician Grace Hobo malfunctioned when debugging the program, and later found that a moth was pinched in the middle of the electric shock, so it was dramatically called "bug", which means flying insects, so the programmer put it. Program failures are called bugs.
In almost the same time period, in 1943, due to the needs of the war, the United States had to undergo a large number of ballistic calculations for experimental artillery. The error rate of manual calculation was high and the accuracy was not enough, so funding was established to establish a research and development headed by John Mauchly and John Eckert. The group, responsible for the development of ENIAC, was born at the University of Pennsylvania on February 14, 1946. ENIAC has high power consumption, high maintenance costs, separation of programs and calculations, and programs are stored in external circuits, requiring dozens of people to reconnect the lines each time. , it takes several days to perform a few minutes of operation. Before ENIAC was successfully developed, von Neumann had already started the design of a new generation of computers. , operator, controller", binary instead of decimal, programs are also stored in memory as data, this design is all common design structures of modern computers, known as the "father of computers".