One, computer classification
1. Divided by scale:
(1) Supercomputer : Super Computer, also known as supercomputer, is used in cutting-edge defense technology and line-generation scientific calculations. The supercomputer's computing speed can reach a trillion times per second. "Tianhe One" is China's first thousand Tera-scale supercomputer.
(2) Large-scale computer : It has high computing speed, can execute tens of millions of instructions per second, and has a large storage space. It is often used for scientific calculation, data processing or as a network server.
(3) Small Computer : refers to reduced instruction set processor, the performance and the price of a high-performance interposed between the PC and the server computer mainframe 64, in China, minicomputers customary to refer to the UNIX server.
(4) Microcomputer : refers to a PC server with an X86 CPU architecture. The central processing unit (CPU) uses a microprocessor chip, which is small and light. It is widely used in commerce, service industry, factory automatic control, office automation and popular information deal with.
2. Divided by function and role:
(1) Server :
Server, a type of computer, usually a high-performance computer that provides various services for client computers in the network. Under the control of the network operating system, the server connects the hard disk, tape, printer, and Expensive dedicated communication equipment is provided to the customer sites on the network for sharing, and can also be used for the network to provide services such as centralized computing, information publishing, and data management.
Servers can be divided into application functions:
Web server, database server, file server, middleware application server, log server, monitoring server, program version control server, virtual server, mail server, print server, domain control server, multimedia server
(2 ) Client :
Client, which makes a request to the server, and the computer that needs the server to provide corresponding services and support.
3. Servers are classified by appearance:
Three common shapes in PC service area:
- Tower server
chassis and structure are similar to the usual vertical PCs, with large chassis space, strong motherboard expandability, and more slots. Not applicable to Internet business companies, the size is not standard. - Blade (Blade) server
Higher density, centralized management, high performance, flexible expansion, on-demand configuration, to achieve high availability and high density. - Rack server The
mainstream server at this stage has standard sizes. It can be used uniformly with the cabinet, which is convenient for statistical management, high density and space saving.
4. Server hardware composition (also complies with von Neumann system):
Power supply, hard disk, CPU, network card, memory, PCI, fan
4.1 Server hardware—CPU:
CPU: Central Processing Unit, that is, the central processing unit , composed of a controller and arithmetic unit, is the most important part of the entire computer system.
4.1.1 CPU architecture:
- CISC:
Complex Instruction Set Computer, complex instruction set - RISC: Reduced Instruction Set Computer, reduced instruction set (mostly used)
4.1.2 CPU type:
- X86 ： CISC
- ARM: Acorn RISC Machine Qualcomm, Huawei Kirin (commercial products, chargeable)
- RISC-V Ali Xuantie 910 (fifth generation, cross-age architecture, Linux in hardware, open source and free)
- MIPS Loongson
- Power: IBM
- Powerpc: apple, ibm, moto
- UItrasparc: Sun.
- Alpha: HP
- Itanium: compag
4.1.3 Server CPU Company
- Intel:
Xeon Xeon
Itanium Itanium - AMD：Althlon MP
- IBM: Power
According to the CPU architecture, servers are mainly divided into two categories:
- X86 server: adopts CISC (Complex Instruction Set) architecture server, which is usually referred to as PC server. It is based on the PC architecture and uses Intel or other compatible X86 instruction set processor chips. Currently, it is mainly Intel Xeon The E3, E5, and E7 series are relatively cheap, with good compatibility, poor stability, and not too high security.
- Non-X86 servers: adopt RISC (reduced instruction set) or EPIC (parallel instruction code) processors, mainly UNIX and other dedicated operating system servers, CPUs mainly include IBM Power PC, MPIS MPIS, SUN Sparc, and Compaq Alpha, HP's PA-RISC, Intel's EPIC Itanium processor, etc. This kind of server is expensive and the system is closed, but it has good stability and strong performance. It is mainly used in the core systems of large enterprises such as finance and telecommunications.
4.2 Microprocessor:
In 1971, the world's first microprocessor, the 4004, was invented by Intel engineers. The performance was low, but the integration was high. Then entered the X86 era.
CPU evaluation indicators:
(1) CPU clock speed : clock speed is the CPU clock speed (CPU Clock Speed), which is the abbreviation of the CPU operating frequency (the number of synchronization pulses that occur within 1 second). The unit is Hz. Generally speaking, the higher the main frequency, the faster the CPU speed. Due to the different internal structure, not all CPUs with the same clock frequency have the same performance.
(2) External frequency: the operating frequency of the system bus, the operating clock frequency of the CPU and the external (motherboard chipset) to exchange data and instructions.
(3) Multiplier: Multiplier refers to the multiple of the difference between the CPU's external frequency and the main frequency. The
relationship between the three is: main frequency = external frequency × multiplier
(4) Cache: high-speed exchange memory, CPU cache is general Divided into level 1, level 2, and level 3 caches, namely L1, L2, and L3.
(5) Memory-Bus Speed: Generally equivalent to the external frequency of the CPU, it refers to the communication speed between the CPU and the secondary cache and memory.
(6) Address bus width: determines the physical address space that the CPU can access.
4.3 Server hardware-motherboard, memory, external storage, hard disk:
4.3.1 Mainboard:
Installed in the chassis, it is one of the most basic and important parts of the computer.
The motherboard is generally a rectangular circuit board, on which the main circuit systems that make up the computer are installed, generally there are BIOS chips, I/O control chips, keyboard and panel control switch interfaces, indicator plugs, expansion slots, motherboards and plug-in cards. Originals such as DC power supply connectors.
4.3.2 Memory:
Memory is between the CPU and external storage. It is a temporary place where the CPU stores program instructions, data and intermediate results when performing high-speed operations on the programs and data in the external storage. Its physical essence is a set of data. High-speed integrated circuits with input/output and data storage functions.
Memory is a storage space that can be directly addressed by the CPU. It is made of semiconductor devices and is characterized by fast access speed.
All programs in the computer run in the memory, so the performance of the memory has a great impact on the computer.
External storage : hard disk, U disk, floppy disk, CD
The difference between memory and external storage :
data is lost after the internal memory is powered off, and data can be saved after the external memory is powered off.
4.3.3 Commonly used technologies for server memory:
- Online spare memory technology
- Memory mirroring
Capacity : the storage capacity of the memory, generally in GB.
Memory bandwidth :
refers to the data transfer rate between the memory and the north bridge chip.
Single-channel memory controllers are generally 64-bit, 8 binary bits are equivalent to 1 byte, and the byte is 64/8=8, multiplied by the operating frequency of the memory, if it is a dual-channel memory Multiply by 2
Calculation formula: memory bandwidth = memory bus frequency × data bus bits / 8
4.3.4 Hard Disk:
Common types of hard disk interface:
- IDE: Electronic integration (drive, common interface for early home computers, parallel)
- SCSI: Small computer system interface, common interface for early servers (parallel)
- SATA: Commonly used interface (serial) for home computers
- SAS: The current mainstream interface on the server (serial)
- Fibre Channel: Interface used on high-performance servers
- M.2: Solid state hard drive interface, with stronger performance. (Current future development trend)
Structure classification:
- HDD (Hard Disk Drive)
- Solid State Drive SSD (Solid State Drive)
Mechanical hard disk: