I know that a sector is the unit in which a track is splitted, but I had this doubt since I was looking for information about the maximum number of pointers that an inode can support. I found that this number depends of the block size. Is this size variable? Is this size maintained when the computer is switched off? Thank you for the help, I have spent some time looking for this but i´m not sure.
Once a file system is established the block size remains the same. Some partitioning tools can change this after the fact, but not while the OS is running.
A sector has traditional been a fixed 512 byte size, but a few drives have 4096 bytes sectors.
A sector is the smallest individual reference-able regions on a disk.
The block size refers to the allocation size the file system uses. The common options are 512, 1024, 2048, 4096, 8192, 16384, or 32678. Generally anything larger would be so inefficient nobody would use it, and you can't go smaller than 1 disk sector.
Sure you can write 10 bytes to a file, but behind the scenes it is allocated 1 block whether you use it all or not.