# Ext4 block Groups

## ksubramaniam

Is group 0 padding of 1024 bytes in ext4 part of 1st block group or does the block group starts after the completion of 1024 bytes ??

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## Bones McCracker

I would avoid terminology like "1st block group", because it causes confusion between block group 0 and block group 1.

As to your question (more information at link):

 *Quote:*   

> For the special case of block group 0, the first 1024 bytes are unused, to allow for the installation of x86 boot sectors and other oddities. The superblock will start at offset 1024 bytes, whichever block that happens to be (usually 0). However, if for some reason the block size = 1024, then block 0 is marked in use and the superblock goes in block 1. For all other block groups, there is no padding.

 

https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout

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