1. What is the programming language?
The first is what language? Language is one thing to communicate with another thing the media
Then the programming language is communication between man and computer media
2 What is the program (what)
Programming programmer you want to do is let the computer do the process
Baidu: To enable the computer to understand the intentions, the idea of humanity must be addressed issues, methods and means to tell the computer in the form of a computer can understand, so that the computer can go to work step by step according to human instruction to complete certain task. This process of communication between people and computing system is programmed
3 programming object (why)
That is, people who want to enslave your computer and let the computer go to work instead of human beings, freeing manpower
4 basic composition of computer hardware
CPU: control and operation (brain)
Memory: store data advantages: access speed drawbacks: Less store data after power loss of data can not be saved (brain)
Hard: store data advantages: multiple data storage, power can be saved for later drawbacks: slow access speed (brain)
Input device: such as a keyboard, a scanner, a mouse, etc. (the input information inside the computer from the outside) (eyes, ears, skin)
Output devices: for example, other display (the output from the computer information) (mouth, hands)
A, CPU details
1, the operation of the CPU: CPU is the brain of the computer, it fetches instructions from memory - ▶ decoding - ▶ performed, and instruction fetch, decode, execute, again and again, until the entire procedure is performed to complete
2, CPU having downward compatibility. 32-bit software can run on a 32-bit CPU, but does not run on 64-bit CPU; however, 64-bit 32-bit CPU can run the software.
Note: CPU 32 indicates a data processing capability 32.
3, microinstruction set in the CPU into RISC and complex instruction set, the former running time of each instruction is very short, to complete the action is very simple, performs better instruction, but if the implementation of complicated things to do , a plurality ARM instructions to complete such a mobile phone the CPU; the latter each small instruction may perform some hardware operation of a lower order, the number of multiple and complex instructions, the length of each instruction is not the same, so that each instruction takes time long, but the work of each individual instruction can handle more abundant, such as AMD, Intel's X86 architecture CPU, etc.
Second, detailed memory
1, register: material manufactured by the same CPU and, as fast as the CPU, so it has no CPU access latency, typical capacity is: 32 * 32 32 to the CPU, the CPU is in the 64 * 64 64, the two capacity were <1KB (immediately prior to use in the data register, temporary storage, in the CPU) the case
2, the cache: mainly by the access control hardware cache memory in accordance with a cache line 0 to 64 bytes of row lines 127 0,64 ~ 1 .. . The most commonly used cache line CPU placed inside or very close to the high-speed CPU cache (often use the data in the cache, temporary storage) When a program needs to read a stored word, the cache hardware required for inspection whether the cache line in the cache
3. Memory: (1) main memory commonly referred to as random access memory RAM, is what we usually refer to the memory capacity has been rising, all can not be found in the cache, main memory will be to find, main memory is volatile storage, disappeared after power failure data; (2) there is a small amount of non-volatile random access storage such as ROM, such as computer boot loader stored in ROM on the module, some I / O cards have the ROM process control the underlying device; (3) EEPROM, and flash memory (camera roll) is nonvolatile, but opposite ROM that can be erased and rewritten and, additionally flash erase times are too worn (4) CMOS. It is volatile, to save the current time and date, battery-driven
4. Tape: greater capacity, slow, cheap, easy to disassemble. Usually store the backup data
5, disk:
The reaction is slow because the disk reading data is slow, the transmission speed is not slow. First position data by mechanical gripping arm, and then read the data rotation
Third, the bus:
Northbridge: the PIC bridge connected high-speed devices
Southbridge: ISA bridge i.e., slow connection device
