What is a Volume header?
Volume Header is the index of every Volume available on that hard drive. Each individual hard drive Volume contains a separate Volume header or a group. Before getting into the details of Volume headers, you need to
Hard Drive Volume: An individual hard drive partition with a single File system.
Header: It is like an index of a book. Whenever the BIOS or the operating system initializes a scan process, the index pointers will look at the MBR - Master Boot Record regarding the number of drives. And only after that, the MBR will point to the Volume headers.
What is the use of Volume Headers?
Though the hard drive looks larger, spatially, it is made up of small bits and bytes of memory spaces grouped as sectors and tracks. For the least, even storing very small data will take lots of bits and bytes. And the data won’t be ordered and grouped in individual separate locations. They are stored wherever available; this information will be stored as hash tables on your hard drives. Volume headers direct the pointer programs to fetch the correct data in that particular hard drive Volume.
What is the size of a Volume Header?
The Volume header size will be less than 1000 kilobytes. The size will be negligible as they have information regarding only the hard drive Volume structure. Some of the information types that the Volume header holds are below.
- File system information
- Volume size
- Volume id
- Used space and available free space
- Meta information about the Index of the primary hash tables, which ultimately has information about the data stored on the Volume
The info may vary based on the operating and file systems.
When Is The Header Volume created?
Normally, these Volume headers are created during OS installation, particularly while formatting the Volume, and are done by the operating system.
What Happens if a Volume Header Gets Corrupt or Deleted?
Whenever a Volume header fails to provide information to the index pointers, it throws an error. These errors regarding the Volume header can be repaired by reinstalling the operating system or reformatting your hard drive. While doing this, you may lose all your data inside the Volume. So be careful while handling these Volume errors. Refer to the link for reformatted hard drive recovery if you have lost data after reinstalling or reformatting the hard drive.
Some samples of error messages found on the Mac operating system are mentioned here...
- The volume Header needs minor repair
- The Macintosh HD Volume needs to be repaired
- Error: The underlying task reported failure on exit
- 1HFS Volume checked
- Volume needs repair
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