From: Michael Harris - NYC SE (
Date: Thu Nov 08 1990 - 18:55:54 CST


Many thanks to all who responded.

Although originally I had something of a technically oriented question
in mind (what does it do? how does it do it? where can I find a white
paper?), the pragmatic nature of this alias came back strong with a
product oriented answer - perhaps the most important - AFS is available
from Transarc Corp., The Gulf Tower, 707 Grant St., Pittsburgh, PA 15219,
(412) 338-4400.

I guess I don't have to summarize Anthony Datri's answer ;) but I will
say that its interesting for a computer person to hear of a product's
developement stages. I mean hey - I don't always like to think about
early versions of what later became my better programs, but I find the
history makes for good nostalgia.

On with the real summary (please correct me if I err).

AFS is a distributed filesystem which allows the filesystem name-space
to be independant of filesystem servers. It caches remote files locally
in 64KB chunks (as of version 3.0) and reconciles updates with the sources.

One thing which I was most interested in, which nobody mentioned for
certain though it seemed like a logical out growth from its other features,
was the ability to mirror filesystems across different servers. I am
assuming this works but people from Transarc have offered to send me
technical info so I'm sure I'll find the answer there. I'll retract if I'm

There was some mention of name service difficulties being fixed in 4.0
(Now where have I heard that before ;) ;) ;)

I must say that the concensus is hats off to Transarc for a good product
and good staff.

Here are the interesting excerpts from the responses (including a

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>>>>> On Wed, 7 Nov 90 20:09:03 -0600, "Anthony A. Datri" <convex!> said:

> Of course, that was a few years ago; I suspect that things are
> different now.

It certainly is! AFS still has problems, particularly in the case of
name service (locating the server(s) for a particular volume), which
are being worked on for AFS 4.0, which is scheduled to come out next
spring or sometime thereabouts. But the problems you describe have
been ameliorated considerably in the current release of AFS (3.0).

Also, a maintenance relase of AFS is scheduled to be released in
January that will have additional fixes, better backup capability,

> A bunch of people from the ITC at CMU seem to have
> gotten together with some of my former coworkers at Unilogic/Scribe,
> who, having wrecked one company, wanted a new one, and called
> themselves Transarc. They're now the people who sell AFS, and I
> believe that IBM is still heavily involved.

I don't know about IBM involvement, but the people I've dealt with
from Transarc have been very professional and competent people.
They've been among the most cooperative computer-related companies
I've dealt with. How enlightened Transarc is vis a vis its business
decisions etc I have no idea. But I've been eminently satisfied with
their treatment of me as a customer.

> If you want more accurate information, try sending mail to
> I believe that she's the right person to contact.

That's correct. Liz Hines is one of the key developers working on AFS
right now. Mike Kazar <> is another.

> Oh yeah -- please don't mention my name.

Heh. I hope you realize that you plastered your comments all over the
world. *Lots* of people read the sun-managers mainling list. (AFS
users, even! :-)


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proceedings of Usenix, Winter 1988 (Dallas) covered both Andrew and
Athena. Try for information.

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I've been running AFS on a cluster of around 150 SS1s that I maintain (mit around 4
4/490s as servers). Having nearly gone berserk trying to use NFS to maintain both
performance and ease of maintainence/use, i can atttest to the fact that AFS is literally a
godsend. There were some performance issues in earlier versions, but it's incredibly neat
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Here's a recent bibliography. If you send me your mailing address,
I can have reprints of some of these articles sent to you, as well as
other literature on AFS and Transarc.


J. H. Howard et al, "Scale and Performance in a Distributed File System,"
ACM Transactions on Computer Systems, Volume 6 No. 1 (February 1988).

J. H. Howard, "An Overview of the Andrew File System," USENIX Conference
Proceedings, pp. 23-26 (Dallas, Winter 1988).

Michael L. Kazar, "Synchronization and Caching Issues in the Andrew File
System," USENIX Conference Proceedings, pp. 27-36 (Dallas, Winter 1988).

Alfred Z. Spector & Michael L. Kazar, "Uniting File Systems," UNIX Review,
March 1989.

Michael L. Kazar, Bruce W. Leverett et al, "DEcorum File System Architectural
Overview," USENIX Conference Proceedings (Anaheim, Summer 1990).

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Many thanx once again to:

Paul Graham <>
Manavendra K. Thakur <>
convex! (Anthony A. Datri)
Matt Crawford" <>
Kerien Fitzpatrick <>
mark@DRD.Com (Mark Lawrence)
oneill@SLCS.SLB.COM (Dennis O'Neill) (Mahesh Subramanya) (Frank P. Bresz)

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