[Info-vax] Request description of UFS for VMS person

[Bob Eager]

On Thu, 30 Apr 2009 18:21:29 UTC, AEF <spamsink2001 at yahoo.com> wrote:

> The whole point of "everything in Unix is a file" to me means that you
> can treat all these things as files the same way. In ODS-2 everything
> is a file or is in a file. You can dump any file, even the pagefile! I
> don't have to write no stinkin' utilities. I can use file commands on
> VMS files. I can't use file commands on the super block or an inode.
> So in my book they are not "files". If files are as you define them,
> then the claim "everything in Unix is just a file" becomes
> meaningless.

You're getting hung up on this phrase, which was just a shorthand for 
"everything in UNIX can be accessed by file I/O operations".

So, to use 'od' on the superblock in my FreeBSD system:

dd if=/dev/ad4s1a skip=65536 count=1  

and pipe it into 'od' (I didn't show that as this newsreader is refusing
to do the pipe symbol)

Of, course, that's just one superblock; there are usually many copies.

> I just want to know in what sense super blocks and inodes are files.

Not sure where you got the original quote from anyway. It's a loose way 
of saying that all I/O is via files. OK< you may think it's a 
shortcoming that bits of disk data structures aren't available directly 
as their own files (they are available as parts of files, though). But 
that's just VMS-centrism. One could equally well complain that you have 
to write special programs to change obscure modes on devices in VMS, but
you don't on UNIX.

Different doesn't mean bad. Live with it.

-- 
Bob Eager