Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!usc!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!ucbvax!mtxinu!sybase!orion!wolfe
From: wolfe@orion.sybase.com (Dave Wolfe)
Newsgroups: comp.os.misc
Subject: Re: More questions about Amoeba and Capabilities
Message-ID: <13353@sybase.sybase.com>
Date: 18 Jun 91 18:23:43 GMT
References: <2623@amix.commodore.com>
Sender: news@Sybase.COM
Organization: Sybase, Inc.
Lines: 29

In article <2623@amix.commodore.com> skrenta@amix.commodore.com (Rich Skrenta) writes:
>Two questions for fans of Amoeba or other capability-based systems.
>Question #2:
>The bullet file server returns a capability when you ask it to create a
>file.  The capability must be presented to perform operations on the file
>such as read, write and delete.
>
>Presumably you're supposed to add this capability to a directory or otherwise
>responsibly manage it.  But what if you "lose" it?
>
>The capability is not stored anywhere, but the bullet file server doesn't
>know this.  There is an unreferenced file on the file server with no
>way to "garbage collect" it.

Why do you say there is no way to garbage collect it? We had a similar
problem at BiiN with our file system (also capability based). We
called these files "unnamed files" and actually considered them a
feature (temp files). What we did was inform the file server every
time the active representation (in core) of a file object was being
garbage collected. The file server decided whether the file was
unnamed or not. If it was unnamed the disk space was deallocated.

I don't know what Amoeba does, but I will bet it is similar.

-DaveW

>Rich
>--
>skrenta@amix.commodore.com