table of Contents
Programming computers
What is the programming language
Programming language is the medium of exchange between man and computer
What is programming
Programming is the use of a programming language files
Why Programming
To slave computer, freeing up labor to help a human to complete a specific task
Principles of Computer Organization
Five computer composition
CPU
Controller
Control hardware
Operator
Logical arithmetic operation +
RAM
Hardware store data temporarily
- Advantages (compared to the external memory): Fast
- Disadvantages (compared to external memory): temporary storage on / off disappears
External memory
Permanent data storage hardware
- Advantages (compared to memory): permanent storage
- Disadvantage (compared to memory): Slow
input device
Hardware input information, such as a keyboard / mouse / U disk
Output Device
Hardware output information, such as a monitor / printer / U disk
I / O device
To enter information, but also information about the hardware, called the I / O device
32 and 64
# 32
A performance reading binary 32-bit operating system
# 64
A performance reading 64 bit operating system
Multi-core CPU
Multi thing can be done at the same CPU, such as 4-core CPU is a large integrated four small CPU CPU
Hard Disks Work
Mechanical hard disk works
- Robot: Find data
- Track: storing data
- Sector: dividing track
- Average seek time: Due to limitations of industry standards, is 5ms
- Average delay time: in the hard disk 7200r / min for example, is 4.15ms
\[ 7200(r/min) / 60 = 120(r/s) \\ 1/120(r/s) = 0.0083s = 8.3ms \\ 8.3 / 2 = 4.15ms \\ \]
- The average time to find Data: 5 + 4.15 = 9.15ms
SSDs works
- Based on the algorithm stored in external memory and electricity
Computer operating system
What files are?
A virtual unit of the operating system
What applications are?
The application is actually a bunch of files, used to complete a specific task
Operating system can you do?
Receiving the application / external command person, then the control hardware
Computer three major components?
application
The application is actually a bunch of files, used to complete a specific task, with others operating system interaction /
operating system
Receiving the application / external command person, then the control hardware, human interaction / applications / hardware
hardware
The ultimate goal is to store data and interact with the operating system
Starting and operating system to start the application?
Start the application
- Double-QQ (send instructions to the operating system)
- Operating system receives the instruction, the instruction is converted into 0 and 1 to a CPU
- CPU receives the instruction, to a memory
- Qq Remove the memory from the hard disk the program is executed, open qq
Operating system boot
- Press the power button (to start a temporary operating system)
- The real wake-up temporary operating system operating system
Programming Language Category
Machine language
- Advantage (assembly language): high efficiency
- Shortcoming (assembly language): the development of low efficiency
Assembly language
- Advantage (machine language): the development of high efficiency
- Shortcoming (machine language): Low efficiency
High-level language
Interpreted language
Like simultaneous interpretation, written translation of a one
- The advantages of (a compiled language): the development of high efficiency
- Shortcoming (a compiled language): Low efficiency
Compiled language
Similar to Google Translate, finish all the code, compile-time to get the results, and results can be saved, can not get timely feedback error
- Advantage (interpreted language): high efficiency
- Shortcoming (interpreted language): the development of low efficiency
Network bottleneck effect
Since the data transmission network may 10ms, while Python code running time code running time of 1ms, machine language is 0.001ms, before you transport data over a period of success, regardless of your code run time is 1ms, or 0.0000001ms, or 9ms, nothing different in essence, this is the bottleneck in the Internet network.