Chapter 1 basic knowledge, Chapter 1

Chapter 1 basic knowledge, Chapter 1
Computer System: Computer Hardware System:

Von noriman system: memory, controller, storage, input, and output

Moore's law: it was proposed by one of Intel's founders, Gordon Moore in 1965. When the price remains the same, the number of components on the integrated circuit will double every 18-24 months, performance will also be doubled.

Computer performance ranking Website: www.top500.org

View the storage unit in windows: Right-click the hard disk and choose Properties> quota> enable quota management to view the Unit

B, KB, MB, GB, TB, PB, EB, ZB, YB, BB, NB, DB

Among them, 1B (bytes) = 8bit

ASCII code: one English letter occupies one byte space, and one Chinese Character occupies two bytes Space

UTF-8 encoding: an English letter occupies one byte space, a Chinese character occupies three bytes of space

Unicode encoding: one English letter occupies one byte space, and one Chinese Character occupies two bytes Space

Different order of magnitude

Server types: tower servers, rack servers, and blade servers

Servers 1U = 1.75 inch = 44.45mm, usually with 1U, 2U, 4U, 5U, 7U standards

CPU:

Clock speed: the clock speed is the clock frequency of the CPU. It is short for the operating frequency of the CPU operation (the number of synchronous pulses occurred within 1 second). The Unit is Hz.

External frequency: the operating frequency of the system bus, CPU and external (Motherboard chipset) exchange data, command clock frequency

Multiplier: A multiplier refers to a multiple of the differences between the external frequency of the CPU and the main frequency.

The relationship between frequency = frequency x frequency

There are two types of CPU architecture: A simplified instruction set and a CISC complex instruction set)

Simplified Instruction Set: General commands solve 80% of problems, and the remaining 20% problems are solved by combining multiple commands. Good stability and performance, mainly used in some minicomputers.

Complex Instruction sets: all requirements are completed using corresponding commands, which is relatively complicated. Intel Xeon E3, E5, and E7 series are mainly used. They are relatively inexpensive, have good compatibility, and have poor stability. The security is not too high.

Memory and external memory:

Memory: data loss caused by power failure

External Storage: power-off data can be saved

Memory bandwidth:

Memory bandwidth refers to the data transfer rate between memory and beiqiao Chip

The single-channel memory throttlers are generally 64-bit. The 8 binary bits are equivalent to 1 byte, And the converted bytes are 64/8 = 8, multiplied by the memory running frequency, DDR (Double Date Rate, dual-channel) memory is multiplied by 2

Calculation formula:

Memory bandwidth = memory bus frequency x Data Bus bits/8

For example, DDR2 667, the operating frequency is 333 MHz, and the bandwidth is

333x2x64/8 = 5400 MB/s = 5.4 GB/s

Hard Disk: mechanical hard disk and SSD Hard Disk

Hard Disk interfaces: IDE, SCSI, SATA, and SAS

Byte = B = 8bit

The gigabit Nic is 1000 Mb/s.

Storage Network:

DAS ----------- Direct Attached Storage)

Storage devices are closely connected to hosts. Data Type: data block

NAS ----------- Network Attached Storage)

A lan is used to interconnect multiple file servers and share files based on the file protocol. It can only be accessed and cannot be managed. Data Type: File

SAN ----------- Storage Area Network (Storage Area Networks)

The high-speed optical fiber network is used to connect servers and storage devices, and storage is shared based on SCSI, IP, ATM, and other advanced protocols. Data Type: data block

Computer Software System:

Application Software:

Text Processing Software

Real-time Control Software

Information Management Software

Auxiliary Design Software

System software:

Compile software

Database Management System

Operating System:

Hardware driver

Process Management

Memory Management

Network Management

Security Management

File Management

Development interface standards:

ABI: Application Binary Interface, which is the underlying Interface between the Application and the OS.

API: Application Programming Interface, Interface between source program and Library

POSIX: Portable Operating System Interface

A series of API standards defined by IEEE on the Operating System

POSIX-compatible programs can be compiled and executed in other POSIX operating systems.