What does the letter »r« stand for in /dev/sr0?

[Detlef Lechner]

Loïc Grenié wrote:
> 2009/11/1 Detlef Lechner <Detlef.Lechner at gmx.net>:
>> Hi,
>>
>> what does the letter »r« stand for in /dev/sr0?
>> (/dev/scd0 is a link to /dev/sr0.)
> 
>    Read-only ?

Hm.

Detlef