Path: utzoo!attcan!uunet!cs.utexas.edu!wuarchive!gem.mps.ohio-state.edu!tut.cis.ohio-state.edu!ucbvax!hplabs!hp-sdd!megatek!igw!rgs
From: rgs@igw.megatek.uucp (Rusty Sanders)
Newsgroups: comp.os.aos
Subject: Re: How to find *real* file sizes in AOS/VS...?
Message-ID: <741@megatek.UUCP>
Date: 22 Sep 89 18:23:38 GMT
References: <1702@murdu.oz>
Sender: news@megatek.UUCP
Lines: 42

> 	After trying to understand the AOS/VS filesystem, I have become
> more confused than ever. What I have tried to do, is to show how much _real_
> disk space is used by a file or group of files.
>
> [...]
> 
> So if there are any Data General employees or hackers out there, maybe you
> could enlighten me?

Well, I'm not currently a DG hacker, but in a previous life I used to be
(I do unix/Sun stuff now, much nicer as far as I'm concerned). Anyway,
you're right. What you are trying to do is VERY difficult with the AOS/VS
I remember (it's been a few years, so things MIGHT of changed, but I doubt
it).

Anyway, quite a long time ago I wrote a little program to do just what you're
asking about. You ran it on a filesystem and it generated a nice listing
of all files (in size order), and their actuall sizes. It is possible to do,
but it's not at all easy.

What do you have to do? Well, first thing is to dismount the filesystem.
This means you can't do it on the root, but that's just tough (actually,
I re-wrote it to run under MP-AOS, and booted it from a floopy when I wanted
to size the root, but I won't ever admit it). Anyway, the trick is to read
the raw disk device, traversing the directory structures, and reading all the
raw index blocks for all the files.

Sounds like a pain? You bet it was. Fortunately, DG provides (or at least
used to provide) a internals document that described the file sructure.
If you're still interested contact your local friendly neighborhood DG
sales engineer (does DG call them applications engineers?) and see what you
can shake loose.

Either that, or beat them up to provide a decent O/S interface that allows
you to find things like this out.

And don't ask if I still have that program handy. It long ago was lost in the
abyss of corporate hyjinks and layoffs. Of course, if you wanted to hire me
as a consultant.....
----
Rusty Sanders, Megatek Corp. --> rgs@megatek or...
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