Centos SYSTEM INTRODUCTION

1. What is centos?

Centos, full name: community enterprise operating system (community enterprise operating system), is a free-to-use source code enterprise-level Linux release based on Red Hat Enterprise Linux. After Red Hat 9.0 is released, Red Hat 10 and 11 are no longer developed. The development of Red Hat Enterprise Linux (RHEL for short) is different from that of Red Hat Enterprise Linux, the new Red Hat Enterprise Edition requires users to purchase lisence first. Red Hat also promises to ensure product stability and security. The RHEL binary code is not provided for download, but is part of the Red Hat service, but the source code is still open. In this case, a number of enterprise versions of open source, such as centos and whitebox, are available, among which centos is the most active. Centos is compiled from the source code released by Red Hat Enterprise Linux according to open source code regulations. Because of the same source code, some servers that require high stability use centos instead of the commercial version of Red Hat Enterprise Linux. The difference between the two lies in that centos does not contain closed source code software. Centos of each version is supported for seven years (through security update ). The new centos version is released every two years, and the centos version is updated regularly (about every six months) to support new hardware. In this way, a secure, low-maintenance, stable, highly predictive, and highly repetitive Linux environment is established.

Centos is a community of Open Source Software contributors and users. The centos community has downloaded the RHEL source code and re-compiled it to become one of the many communities that have released new versions. As as/ES/WS is a commercial product, you must change all Red Hat logos and logos to your own centos logos. For example, after compiling the original srpm source code of as4.0 and replacing it with the logo of the centos community, it became centos 4.0. After the Red Hat Enterprise Linux as4 update1 source code is compiled, it becomes centos4.1.as4 update2 after the source code is compiled, it becomes centos4.2 and so on. This is how centos is generated. Therefore, centos is the free version of Red Hat as/ES/WS. centos provides the same features and performance as Red Hat Enterprise Linux. At the same time, centos also provides free long-term upgrade and update services. Therefore, among the many clone versions of RHEL, centos is outstanding. Although centos is a RHEL clone, it is not exactly the same. It is 100% interchangeable. For centos, The RHEL software does not guarantee 100% normal operation on centos. The centos community is constantly integrated with other similar communities, making centos Linux the most widely used RHEL compatible version. Centos Linux has no better stability than RHEL. The only drawback is the lack of technical support because it is a free version released by the community.

Centos Linux has a strict version correspondence with RHEL products. For example, if RHEL4 source code is used to re-compile and release centos Linux 4.0, rhel5 corresponds to centos Linux 5.0, rhel6 corresponds to centos Linux 6. Due to the long life cycle of RHEL products (usually 3 ~ 5 years of official support), So Red Hat repacks the accumulated update program into an updated release every time after the RHEL product series are released, it is usually called RHEL update. For example, the first update version of rhel5 is called RHEL 5 Update 1, and the user is also called RHEL 1st. For each RHEL update centos community released by red hat, a corresponding update release version will be released, for example, the source code package of the update 1 program based on RHEL 5, centos will re-compile and package and release centos Linux 5.1. In centos Linux, The RHEL release with the corresponding version has binary compatibility at the software package level, that is, if an RPM package can be installed and run in RHEL, you can normally install and run in centos Linux of the corresponding version. Because centos Linux is compatible with RHEL and stable for enterprise-level applications, and allows users to use it freely, it is widely used.

2. centos features

Centos can be understood as the Redhat as series. It is released after improvements to red hat. There is no difference between various operations and use and red hat.

Centos is free of charge and there is no problem that Red Hat as4 requires serial numbers.

The yum command exclusive to centos supports online upgrades and real-time system updates. Unlike red hat, it requires money to purchase support services.

Centos fixed many red hat as bugs.

Centos version Description: centos3.1 is equivalent to RedHat as3 update1, centos3.4 is equivalent to RedHat as3 update4, and centos4.0 is equivalent to RedHat as4.

3. Official website and documents

Official homepage: http://www.centos.org/

Official wiki: http://wiki.centos.org/

Official Chinese document: http://wiki.centos.org/zh/Documentation

Installation instructions: http://www.centos.org/docs/

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Centos SYSTEM INTRODUCTION