Learning Log---linux punch 1

Direct operation of the hardware, by the CPU's privileged instruction set to operate, the general operation is a common instruction set. The CPU has instruction sets, and different CPUs may have different instruction sets.

Api:application programing Interface

Abi:application Binary Interface

Ansi:

Pre-compilation is the call API, compiled by the ABI, where the program is compiled where it runs.

Pre-processing, compiling, compilation, links

Dll:dynamic link Libraries dynamic link library on window

So:shared object on Linux

During the link phase, the corresponding library file is loaded into memory to run the program.

The operating system itself has many standard libraries that can be called by the upper layer, typically C. The creation of a process is typically a request Shell,shell run as a parent process to establish a child process.

Linux:gnu/linux
Recursive abbreviation: GNU is not Uinx
GPL, GPLv2, GPLv3, LGPL copyright or owned by others, open source can only be used
Bsd
Apache

Copyrights: Copyright, copyleft

@ Extracurricular Expansion: Learn about these open source agreements;

Some of the most common versions of Linux:
Redhat, SuSE, Debian

Package Manager:
A program typically has four types of files: binaries, configuration files, library files (for others), Help files

A package manager for Dpkg,debian;
Rpm:redhat is also a package management tool.

Knowledge:
x86-64, CentOS 6.4 32bits, test-3.2.1-cetnos5.x86.rpm
This means that the 32-bit machine compiled with CENTOS5, does not match the previous CENTOS6 version, and does not install successfully, because it is possible that the library is different.
x86-64, CentOS 6.4 32bits, test-3.2.1-el6.x86_64.rpm
The following el6.64 indicates that the CENTOS64-bit operating system library is compiled on the CENTOS6 64-bit system.

When an application accesses the kernel, it can call the library, and some can call it directly, called a system call.
The shell is a shell that allows the user to invoke the application to run on the kernel through it.
The kernel source code for Linux is supported on all platforms, but the supported platforms are specified after compilation because they support different libraries and CPU instructions vary.

FileSystem: File System
is on the kernel, dealing with hardware. is part of the kernel and provides system calls externally.
The network module is also a sub-function module of the kernel, because the kernel can access the network card, if at the application layer, every time the system calls, the speed is too slow.

General Software
Kernel (Kernel):
Features of the kernel:
File system
Network protocol stack
Process Management
Encryption/Decryption
Drivers: such as inserting a new hard disk, the kernel will load the driver (corresponding to the application driver is already available in the OS), to operate the drive, so the driver, such as toxic harm will be very large.

The switching relationship between the operating system and the process on the CPU:
On the CPU, the operating system and the application in the non-stop switch, the operating system to select the task List of the process into the CPU execution, after the operation of the operating system to occupy the CPU, select the next, if in the execution process of operating hardware operations, such as the CPU's privileged instructions (such as creating files, etc.), The process gives the operating system the CPU, completes the privileged operation, returns to the process after the operating system completes, and then resumes execution.

Application software

Basic content of Linux:
System Management: Network, file (create, delete, move, permission), user, file system, encryption/decryption, kernel (compile), boot process, package management;
Network Service Management: Web (Apache, nginx, MySQL, PHP), nfs/samba/ftp (file service), Postfix/dovecot (mail Service), network security (Iptables,
Tcp_wrapper), DNS (based on this implementation CDN);
Mysql:crud, index, storage engine, backup, recovery, replication, cluster, shard;
Cluster: LB (load Balanced cluster), HA (High availability cluster), GFS (global file system);
High-scale Web:nginx, Haproxy, keepalived, Tomcat, Distributed File System, CDN, NoSQL
Virtualization (Hardware-based): Xen, KVM, LXC/OPENVZ (Virtualization implementation of container classes)
Iaas:openstack (cloud virtualization), etc.;
Automated operation and maintenance: Automation management, monitoring, puppet,python programming, etc.
Massively parallel Processing platform: Hadoop implementation Mechanism, configuration and use;
System principle and optimization

Red Hat Company: RHCSA, RHCE, RHCA

Learning Log---linux punch 1