Computer System : The system consists of two major computer hardware and software system components;
Hardware: the host and external devices;
System software: system software and application software;
Computer: one kind can receive and store information, and automatic and efficient mass data processing according to a program stored therein, and the modern intelligent electronic device and the processing result;
Development of computer history: the first generation of computers (1946-1957) vacuum tube era
Second generation computers (1958-1964) of the transistor era
Third-generation computers (1965-1970) integrated circuit era
The fourth generation of computers (1971- later) LSI era
Computer hardware components: · calculator, controller, memory, input devices, output devices;
Computer classification (by size division): supercomputers, mainframes, minicomputers, microcomputers;
Server: A computer is a network that provides various services to the client computer performance computer; server under the control of the network operating system, a hard disk, magnetic tape, a printer, and expensive dedicated communication device available on the network connected thereto customer sharing sites, also provides centralized computing for network users, information dissemination and data management services;
Classification server (by appearance): tower server, blade server, a rack server;
(According to application functions): Web servers, database servers, file servers, middleware, application servers, log servers, monitoring server, version control server, a virtual machine server, mail server, print server, domain control server, media server, communications server , ERP server;
CPU: central processing unit; constituted by a controller and operator, the entire computer system is the most important part;
CPU type: X86, X64, ARM, m68000, Power, Powerpc, Ultrasparc, Alpha, Itanium;
Server hardware - Board: The computer of the most basic and most important member; generally rectangular circuit board above the main circuit composed of a computer system is installed, generally BIOS chip, I / O control chip, a keyboard and control panel switch interface lamp connectors, expansion slots, card board and DC power supply connector element and the like;
Server hardware - Memory: memory storage capacity, ie, the unit is generally "MB" or "GB";
Server Hardware - hard disk:
Hard basic parameters: capacity, speed (referring to the number of turns of rotation of the disk platter per minute, RPM unit), the transmission rate (the speed at which the hard disk write data, the unit MB / s), the cache;
Server hardware - array card: Raid card;
Server Hardware - Graphics: the graphics processor;
Server hardware - Cabinets: rack servers in the enclosure;
Operating System (OS): general-purpose software programs;
1: hardware drivers
2: Process Management
3: Memory Management
4: Network Management
5: Security Management
6: File Management
OS Category:
Server OS: RHEL, CentOS, Windows Server, AIX;
Desktop OS: Windows 10, Mac OS, Fedora;
Mobile device: Andriod, IOS, AliOS, HarmonyOS;
ABI: describes the interface between the underlying application and the OS, allows compiled object code compatible ABI systems can be run without change;
API: defines the interface between the source code and libraries, so the same source code can be compiled in any system in the API;
POSIX: Portable Operating System Interface, which is compatible with the operating system can compile and run the program in other POSIX;
System call: the demand for non-general use, the operating system provides a series of function calls to the software developer, to implement some of the features users need software developers; these function calls are called system calls;
Programming language:
Low-level language:
Machine language: 0 and 1
Assembly language: and machine language correspondence, specific code, drivers associated with hardware development;
Intermediate Language: C
High-level language : the Java, Python, Go, PHP, in Objective-C, C
Three server system:
Windows;
Linux:GUN/Linux
Unix: 1969 years Ken Thompson
System：Bell Lab
AIX（IBM）
Solaris（SUN）
HP-UX (HP)
BSD：（BSRG）Berkeley System Distribution
NetBSD
OpenBSD
FreeBSD
The evolution of the operating system:
Single-user system
Batch system: improve system efficiency
Multiprogramming system: programmed CPU processing procedure
Timesharing system: increase system utilization, CPU operating system controlling processing sequence
PC: Each user corresponds to a system, cheap, convenient, easy to use
Distributed computing: a plurality of systems corresponding to each user, the cloud, large data processing