Chapter 0 - Introduction to Computers

0.1.1 Five major units of computer hardware: input unit, output unit, CPU (central processing unit, is a chip with special functions) internal arithmetic logic unit, CPU internal control unit ,RAM. 0.1.2 CPU type:     (1) Reduced Instruction Set System (RISC): The current scope is the widest     (2) Complex Instruction Set System (CISC): Mainly used for computers with X86 architecture such as AMD, Intel, VIA. 0.1.3 interface device: main board, storage device, display device, network device········ 0.1.4 operation process:     CPU=brain;     Memory = recorded blocks in the brain, acting as a temporary storage;     Hard disk = recorded block in the brain;     Motherboard = nervous system;     Interface equipment = hand, eye, foot ·······;     Graphics card = influence in the head;     Power = heart; 0.1.5 computer classification: supercomputer, mainframe computer (multiple CPU), minicomputer, workstation, microcomputer; 0.1.6 Calculation unit on the computer: One bit on the computer is the smallest unit, followed by 1Byte=8bit. It should be noted that the computer operating system uses binary, while the operator uses the decimal system for the network. Binary 1M=1024, decimal 1M=1000.

0.2 personal computer architecture and interface equipment (currently two major x86 architecture CPU manufacturers AMD and Intel) 0.2.1CPU Multi-core: The so-called multi-core is a CPU shell that contains multiple CPUs. CPU frequency: The number of times the CPU works per second. Frequency = FSB X multiplier. CPU FSB: The speed at which the CPU and the external computer perform arithmetic data transmission. Multiplier of the CPU: One speed of the CPU for acceleration. 32-bit and 64-bit: There are 32 and 64 bits depending on the block size that the CPU can parse, that is, the maximum amount of data transmitted per second. Here, the bit refers to the bit bit. 0.2.2 memory ROM read-only memory: A read-only memory is a type of memory that can also record data in the event of a power failure. 0.2.3 graphics card: The graphics card has memory and also has computing power. A 3D accelerated chip embedded in the graphics card by the manufacturer is called GPU. (The resolution product is equal to the total pixel, the total number of memory occupied by each pixel = the memory required by the graphics card at least). 0.2.4 Hard Disk and Storage Device: All data in the hard disk is actually written on the disk. The smallest unit of data stored on the disc is the sector, and each sector size is always 512 bytes. The entire hard disk is cylindrical, and the capacity of the entire hard disk can be calculated by using one planar sector as a basic unit, which is similar to calculating the volume of a cylinder. The interfaces currently used to transfer data between the hard disk and the system are as follows: IDE interface, SATA interface, and SCSI interface. Buffer memory: Stores commonly used data on the hard disk to speed up the system's read performance. Speed: The number of turns of the spindle motor to rotate the disk to access the data. 0.2.5 PCI adapter card: PCI interface can be used for a variety of purposes, such as network cards, sound cards, special function cards.

0.3Data representation 0.3.1 digital system: binary is used in the computer system, only 0 and 1 are recognized; when we write the text data of the file, the text data will be converted into the numeric data consisting of 0 and 1 by the code comparison table. And then save it in the file. Similarly, when we need to read the data in the file, the numeric string corresponds to the code comparison table, converts the digital string into the corresponding text, and then outputs it to the display or other device. The commonly used English code table is the ASCLL system. In this coding system, each symbol (English, number, symbol, etc.) will occupy 1B record, which is changed by 2 8th. The so-called Unicode encoding system customized by the international organization ISO/IEC, which we call UTF8 or Unicode, solves the garbled problem in various countries.

0.4 Software program running     0.4.1 Machine Programs and Compilers: Knowing machine programs and compilers requires an understanding of machine language and related functional functions of the hardware. Machine programs and compilers are not portable, that is, programs are specific.     0.4.2 operating system:         1 Operating System Kernel: An operating system is actually a set of programs that focus on managing all the activities of a computer and all the hardware in the drive system. The set of functions that this set of programs can implement is called the operating system kernel. (Kernel). The location where the kernel program is stored in memory is protected and remains in memory after booting.          2 system call (system call): The operating system usually provides a whole set of development interfaces for engineers to develop software, engineers combine the parameters of these interfaces, use the corresponding programming language to write the corresponding interface program, so that the kernel can run the program . The interfaces provided by the operating system belong to the system call layer in the operating system. The role of the operating system is roughly represented by the following figure:这里写图片描述。 *操作系统的内核是直接参照硬件规格写成的,因此同一个操作系统不能在不一样的硬件架构下运行。操作系统只是在管理整个硬件资源,包括CPU,内存,输入输出设备和系统文件,而实现其他多媒体功能还需要其他的应用软件。应用程序的开发都是参照操作系统提供的接口的,所以该应用程序只能够在提供参考接口的操作系统上运行。 *内核的主要功能:内核的主要功能包括上面提到的系统调用接口,程序管理,内存管理,文件系统管理,设备驱动等。 **操作系统与驱动程序:驱动程序是操作系统中相当重要的一环,我们想要计算机使用某个硬件或者软件的功能时,就需要计算机使用驱动程序驱动这些硬件或者软件,通常操作系统会向开发商提供一些可以开发驱动程序的接口,基于这些接口,开发商开发相应硬件或者软件的驱动程序,使操作系统可以运行这些硬件或者软件。