In Unix systems, what is the difference between the main memory index node and the secondary index node in terms of content, why set the main memory index node?

Source: Internet
Author: User

Main Memory index node and secondary index node are mainly reflected in: Memory index node State; Device number, index node number; reference count.

Main Memory Index node state-reflects the use of main memory index nodes. It indicates the following:

1, whether the index node is locked;

2. Whether there is a process waiting for the index node to become unlocked state

3, as a result of changes to the data in the index node, the main memory of the index node indicates whether it is different from the contents of its disk.

4. As a result of changes to the file data, the main memory of the file indicates whether it is different from the contents of its disk.

5, whether the file is the installation point.

Device number, index node number. Corresponds to the location information of the secondary index node. The device number is the index node and the device number of the device on which the file resides, and the index node is the number of the index node in the Secondary index node area.

The reference count. Indicates the count of active references to the file.

(The file owner identification number, file type, and other items are the same as the contents of the secondary I node.) )

In order to improve the system efficiency, reduce the main memory space occupied.

In Unix systems, what is the difference between the main memory index node and the secondary index node in terms of content, why set the main memory index node?

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.