Re: filesystem or database??

[mohit verma]

hello ,
when we  install any package the terminal shows in end " reading database"
(used by package manager like .deb or rpm). but as in linux everything is
nothing but a file. so database shown above must be a part of the filesystem
. so why we not say that " reading filesystem".
what differs and imposes to say filesystem or database differentlly inspite
of one being one subset of other (filesystem)?