IT knowledge infrastructure
First, the teacher recommended books
1. "mathematical beauty" - the Wu Jun
2. "light of civilization" - the Wu Jun
Two, IT knowledge framework (data storage, systems, algorithms)
1. Data storage:
Disk (shared storage architecture):
(1) SAN, NAS, DAS (specifically the disk array data storage); operation and maintenance operations applied to the cloud
(2) distributed memory architectures (the HDFS): clusters (application: micro-channel, QQ ~); data processing applied to a large data
NOTE: HDFS - Hadoop defined file system, H: Hadoop D: defined FS: System
2. Mold:
(1) map-reduces data processing clusters:
It is the data in a certain way, to modify the relationship between the key (key-value)
map-reduces + HDPS = (running on a cluster of high-performance Linux) Hadoopj Cluster
3. operations:
(1) through mathematics (statistics) + Python = algorithm
(2) Data Visualization
Third, the employment direction the IT industry: cloud computing, big data
Fourth, the two frames in the IT industry: operation and maintenance, development
1. operation and maintenance:
(1) Linux operation and maintenance:
web architecture, build their own personal website
(2) the virtual machine KVM / XEN:
open stack, docker (K8S) (running applications)
(3) large data storage direction = Hadoop + Java (a way to develop a so-called)
Hadoop ：HDFS mr Hive（SQL） zookeeper ... ...
2. Develop - computer language
(1) BASIC language, early machine language
(2) C C ++ (once compiled, all of the implementation; the closest high-level language assembler language): systems development, driver development, embedded development (writing board)
(driver: the need to convert a set of instructions between the various equipment manufacturers, so that manufacturers only communicate before)
(3) Front: JS (development site distal) php css html
（4）JAVA
（5）Python
(6) Tool: Scripting languages - shell \ perl \ python
(7) Database: MySQL, nosql
Introduction of the operating system (OS-operating system)
First, why the operating system?
1. Platform - nexus
on: Application
under: a hardware device (resource)
2. Three member (1) hardware platforms: CPU memory I / O devices
(Five components: computing, controller, memory, input devices, output devices)
(2) CPU: all operations, restart the system, the data will not be lost
(3) Memory: action: providing data (cpu read only memory to the data) to the CPU
Reboot the system, the data in memory will be lost
CPU reads the data specified in the memory, the process (required), we called addressable; (address into a physical address, logical address)
(4) IO device: network card (adapter adapter): Ethernet (Ethernet)
(5) disk (IDE, SAS (used to work), SSD) mechanical drive, solid state disk
To Learn More: osi seven layer model --TCP / IP four-layer model
(1) Application Layer --QQ
(2) presentation layer - instruction converter
(3) The session layer establishes a session --session
(4) transport layer - Application distinguished by the port
(5) network layer --IP
(6) data link layer address --MAC, Ethernet cards have only the MAC address (i.e. physical address)
(7) Physical Layer - specific physical device (a hardware device)
Note: lower to the upper to provide services. Three for the upper layer to the application layer, the transport layer is the transport layer, the network layer is called the network layer interl lower layers to the host the host layer.
The operating system itself is a software program, but it does not directly provide customers with the application, but to provide hardware resources for other applications; the operating system is divided: user space and kernel space.
