4

I tried this command on my Linux Ubuntu prompt in Amazon Web Services

sudo file /dev/xvda1

and the output is

/dev/xvda1: block special

What is the meaning of block special in the output?

Braiam
  • 69,112
Gaurav Agarwal
  • 11,913

2 Answers2

3

Most of the things you find below /dev are either "block special" or "character special" things, and you rather to not change them manually. Your example shows a disk drive partition provided by Xen (what on a "normal, nonvirtual machine" would be /dev/sda1).

For more details on this special device, please see What is the “/dev/ xvda1 ” device?

For more details on what devices, and especially block devices are, you may consult Device file - Wikipedia, the free encyclopedia.

Community
  • 1
Izzy
  • 3,620
1

From the Wikipedia link provided by Izzy:

"A special file is an interface for a device driver that appears in a file system as if it were an ordinary file".

"Block special files or block devices provide buffered access to hardware devices, and provide some abstraction from their specifics. Unlike character devices, block devices will always allow the programmer to read or write a block of any size (including single characters/bytes) and any alignment. The downside is that because block devices are buffered, the programmer does not know how long it will take before written data is passed from the kernel's buffers to the actual device, or indeed in what order two separate writes will arrive at the physical device..."

U007D
  • 111