Thomas Graichen forwarded me some interesting information from the
freebsd-fsdevel list regarding 3 patents held by Network Appliance,
Inc., Santa Clara, CA that seem to describe much of the mechanism that
underlies Tux2. I haven't heard anything from any representative of
Network Appliance, which I find very curious because they must certainly
have heard of Tux2 by now. But of course when I do hear from them they
will want something, and I will want them to FOAD.
It is important that all technology used in GPL software be free of
patent restrictions. Unfortunately for Network Appliances, I developed
all the essential concepts they describe in 1989 (the RAID optimization
excepted, see below for what I think about that) and implemented them in
a production system. In other words, I've got prior art; their patents
are worthless. Furthermore, I developed the entire Tux2 design and
implemented most of it before I ever even heard of their software, much
less their patents. And on top of that, other people also have prior
art (check out Auragen, if you don't know what it is, ask Victor
OK, I sense there's going to be a fight, because Network Appliance is a
profit-making corporation and they would be remiss if they didn't try to
defend their IP. Did I mention that software patents are evil? Did I
mention that software patents make people behave in evil ways?
I'm not going to change my course at all, I'm determined to bring this
better idea to Linux in a free and open way. I will continue to develop
it until it's finished. Oh, and the phase tree algorithm is
fundamentally superiour to their WAFL algorithm, as I will demonstrate
next week in Atlanta.
I invite anyone who's interested to email me and help out. Are you a
patent lawyer that likes to work for free? *Especially you*, please
Now let me state my position on patents:
- Patents are evil
- Software patents are especially evil
- Patents, and especially software patents, constitute nothing less
than government-sponsored theft of property that properly belongs
- If we did not have any form of patent, humanity would be better
- If we did not have any form of patent, the world economy would
benefit. Yes, that means corporations too.
- If we did not have any form of patent, *most voters would
benefit* <-- pay close attention to this one
- Patents are anti-capitalist: they interfere with the proper
functioning of the market economy. Patents on business methods
are already rearing their ugly head.
- It's getting worse. If the current trend continues, you will
soon see the life of patents being extended, you will see
patents being granted in areas that were previously considered
off-limits, and you will see countries outside the U.S. being
pressured into supporting the patent system in various ways.
- We can't change the world overnight, but we do already possess
the power, if we excercise it, to send the laws that gave birth
to software patents back into the cesspool they crawled out of.
- In spite of the popular myth about the lone inventor who strikes
it rich, the only real beneficiaries of patents are corporations.
Yes, a few lone inventors strike it rich, but not enough to undo
the damage done to humanity in general. Most lone inventors just
get ripped off by people who prey on them and their dreams.
- If all patents were to vanish today and never come back research
in general would accelerate, not slow down. Linux is proof of
- Lawyers built the patent system. Tim O'Rielly once asked a
patent lawyer how he would feel if other lawyers could patent
legal arguments and charge him money to use those arguments in
court. Though he tried to twist out of answering that one,
eventually he had to admit that he had no answer. This lawyer
IIRC is the director of the U.S. Trade and Patent office.
OK, I'll stop ranting now. I knew it was going to happen, and not only
that, this is going to happen more and more until the evil patent system
is uprooted and composted.
Now, the specifc discussion:
US patent 5,819,292 "Method for maintaining consistent states of a file
system and for creating user-accessible read-only copies of a file
ApplDate 1993-06-03 <- Four years after I did my work.
"A method is disclosed for maintaining consistent states of a file
system. The file system progresses from one self-consistent state to
another self-consistent state. The set of self-consistent blocks on disk
that is rooted by a root inode is referred to as a consistency point.
The root inode is stored in a file system information structure. To
implement consistency points, new data is written to unallocated blocks
on disk. A new consistency point occurs when the file system information
structure is updated by writing a new root inode into it. Thus, as long
as the root inode is not updated, the state of the file system
represented on disk does not change."
*** I did all of this in my database program, which in fact implemented
a complete filesystem on top of the existing filesystem. This was 1989.
"The method also creates snapshots that are user-accessible read-only
copies of the file system. A snapshot uses no disk space when it is
initially created. It is designed so that many different snapshots can
be created for the same file system. Unlike prior art file systems that
create a done by duplicating an entire inode file and all indirect
blocks, the method of the present invention duplicates only the inode
that describes the inode file. A multi-bit free-block map file is used
to prevent data referenced by snapshots from being overwritten on disk."
*** They come close to winning one here, but their multibit free map
loses it for them. I do it with a single bit, and I should patent the
way I do that (GPL of course). Even better, I recently figured out how
to make the Tux2 snapshots *read/write*, and even *exchange* and
*rotate* snapshots. Take that you evil intellectual property barons.
patent 5,963,962 "Write anywhere file-system layout";
"The present invention provides a method for keeping a file system in a
consistent state and for creating read-only copies of a file system.
Changes to the file system are tightly controlled. The file system
progresses from one self-consistent state to another self-consistent
state. The set of self-consistent blocks on disk that is rooted by the
root inode is referred to as a consistency point. To implement
consistency points, new data is written to unallocated blocks on disk. A
new consistency point occurs when the fsinfo block is updated by writing
a new root inode for the inode file into it. Thus, as long as the root
inode is not updated, the state of the file system represented on disk
does not change."
*** Again, I did every last bit of this in 1989.
"The present invention also creates snapshots that are read-only copies
of the file system. A snapshot uses no disk space when it is initially
created. It is designed so that many different snapshots can be created
for the same file system. Unlike prior art file systems that create a
clone by duplicating the entire inode file and all of the indirect
blocks, the present invention duplicates only the inode that describes
the inode file. A multi-bit free-block map file is used to prevent data
from being overwritten on disk. "
*** Same thing again. They lose.
US patent 6,038,570
"Method for allocating files in a file system integrated with a RAID
disk sub-system" (which isn't a patent on WAFL by itself, it's a patent
on the way we try to arrange to write as many blocks in a stripe as
*** Well, I'd have to call this one particularly obvious. In any event,
if they want to argue I think they'll find themselves in a position of
having to kiss their main patents bye-bye.
-- Daniel - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to firstname.lastname@example.org Please read the FAQ at http://www.tux.org/lkml/
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