ASDF AN AUTONOMOUS AND SCALABLE DISTRIBUTED FILE SYSTEM PDF

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ASDF: An Autonomous and Scalable Distributed File System . many of the same goals as previous distributed file systems such as scalability. Distributed File System (DFS) could be a set of consumer and server .. Huang and Huan-Ming Liang, “ASDF: An Autonomous and Scalable Distributed. File. 3 / Abstract. We have simulated SimpleFS, a simple and scalable distributed file system for nowadays highly Other file systems, like TidyFS, ASDF, Ceph, etc, utilize similar concepts but take more .. ASDF: An Autonomous and. Scalable.

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Now, as it traverse d the action graph, ASDF was propagating a force flag indicating whether an action needed to be performed again in the current session due to some of its dependencies itself needing to be updated. Interestingly, this compute-action-stamp could be very easily updated to use cryptographic digests of the various files instead of timestamps, or any other kind of stamp.

The DAG defines a partial order, whereby each action must be perform ed, but only after all the actions it transitively depends-on have already been performed. After Gary King resigned in Novemberwe took over his position, and produced a new version ASDF 2, released in Maythat turned ASDF from a successful experiment to a product, making it upgradable, portable, configurable, robust, performant and usable.

International Journal of Modern Education and Computer Science (IJMECS)

However, these could conceivably be implemented as ASDF extensions. Evolving ASDF was not monotonic progress, we also had many failures along the way, from which lessons can be learned. Most CL implementations maintain their own heap with their own diztributed collector, and then are able to dump an image of the heap on disk, aan can be loaded back in a new process with all the state of the former process.

Failed Attempts at Improvement 8.

dblp: Chi-Chang Huang

As you can see, dependencies name sibling components under the same wn system or module, that can themselves be files or modules. You may have to add: As computer systems grew, they became files on a tape, or, if you had serious money, on a disk. In the end, we implemented an ugly mechanism of “negative inheritance”, to selectively disable the behavior for appropriate subclasses of operation while keeping it for legacy operations see Restoring Backward Compatibility.

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One can now use ASDF to write Lisp programs that may be invoked from the command line or may spawn external programs and capture their output ASDF can deliver these programs as standalone executable files; moreover the companion script cl-launch see cl-launch can create light-weight scripts that can be run unmodified on many different kinds of machines, each differently configured. They still have to otherwise avoid non-standardized behavior and implementation-specific extensions if they want their programs to be portable.

There is also an abstraction layer over the less-compatible legacy implementations, a set of general-purpose utilities, and a sccalable core for the ASDF configuration DSLs. A limited compatibility mode without asff was preserved to keep processing old versions of SBCL. ASDF 3 thus solves this version extraction problem for all software — except itself, since its own version has to be readable by ASDF 2 as well as by who views the single delivery file; thus its version information is maintained by a management script using regexps, of course written in CL.

Bundle operations make delivery of code much easier. However, the most complex piece turned out to be a portable implementation of run-program.

1 Ceph Distributed Storage Sage Weil DreamHost / new dream network April 7, 2011.

You may thus invoke Lisp code from a Unix shell:. ASDF 2 similarly provided sensible rules for pathname types and type overrides.

This caused much grief when we tried to make system not a subclass of module anymore, but both be subclasses of new abstract class parent-component instead.

Considering the massive changes, I decided it should be called ASDF 3, even though a few months ago, I was convinced I would never write such a thing, since ASDF 2 was quite stable and I had no interest in making big changes.

Auttonomous only encoding supported out of the box is: Thanks to CLOS multiple inheritance and syste dispatch, it all fell into place 2. In any case, this all means that nowadays, logical pathnames are always a bad idea, and we strongly recommend against using these ill “logical” pathnames.

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ASDF: An Autonomous and Scalable Distributed File System

Most pathname-handling functions in UIOP tend to accept nil as valid input. And this careful sequencing is baked into the traverse algorithm rather than reified in dependencies of the action graph. Reducing Risk with Cloud Storage.

If the type is nilnothing is added and the type is extracted from the component name, if applicable. Still, the situation is somewhat worse in the CL world: Running Lisp code to portably create executable commands from Lisp is great, but there is a bootstrapping problem: Indeed, this was a great success in making ASDF understandable, if not by newcomers, at least by the maintainer himself; On the other hand, a special setup is now required for the debugger to locate the actual source code in ASDF ; but this price is only paid by ASDF maintainers.

The unintended result of these rewrites was to turn it into a much more robust and versatile product than it asdc Still, because ASDF had been changing so much in the past, and it was hard to rely on a recent version, no one wanted to depend on ASDF for utilities, especially not when the gain was so small in the number of functions used.

The greatest source of portability woes was in handling pathnames: Each component name or explicit pathname override, if given as a stringis combined with the specified file type information and correctly parsed into relative subdirectory, name and type pathname components of a relative pathname object that relative pathname is merged into whichever directory is being considered, that it scwlable relative to.

On the one hand, it minimizes overhead to writing build system extensions.