Free condition software for linux

CSS::SAC::ConditionFactory Perl module contains the default ConditionFactory.

SYNOPSIS

my $cf = CSS::SAC::ConditionFactory->new;
my $cond1 = $cf->create_foo_condition;
my $cond2 = $cf->create_bar_condition;

This is the default ConditionFactory for CSS::SAC. It creates conditions of all types defined in SAC. You may wish to subclass or replace the default ConditionFactory in order to get your own condition objects.

I plan on adding more flexibility to this factory so that one could tell it the classes to use for various conditions, that would avoid enforcing subclassing/recoding for people that only want to replace a family of factory methods.

I know that some of the method names are quite lengthy, but given the great number of possible conditions it helps to have descriptive names.

METHODS

These define the interface that must be adhered to by ConditionFactories. The Java names (given in parens) work too, though the Perl ones are recommended.

CSS::SAC::ConditionFactory->new or $cf->new
Creates a new condition factory object.
$cf->create_and_condition($first,$second) (createAndCondition)
creates a combinator condition of type and
$cf->create_attribute_condition($lname,$ns,$specified,$value) (createAttributeCondition)
creates an attr condition
$cf->create_begin_hyphen_attribute_condition($lname,$ns,$specified,$value) (createBeginHyphenAttributeCondition)
creates a attr condition of type bh
$cf->create_class_condition($ns,$value) (createClassCondition)
creates a attr condition of type class
$cf->create_content_condition($data) (createContentCondition)
creates a content condition
$cf->create_id_condition($value) (createIdCondition)
creates a attr condition of type id
$cf->create_lang_condition($lang) (createLangCondition)
creates a lang condition
$cf->create_negative_condition($cond) (createNegativeCondition)
creates a negative condition
$cf->create_one_of_attribute_condition($lname,$ns,$specified,$value) (createOneOfAttributeCondition)
creates a attr condition of type id
$cf->create_only_child_condition() (createOnlyChildCondition)
creates a only-child condition
$cf->create_only_type_condition() (createOnlyTypeCondition)
creates a only-type condition
$cf->create_or_condition($first,$second) (createOrCondition)
creates a combinator condition of type or
$cf->create_positional_condition($position,$type_node,$same_type) (createPositionalCondition)
creates a positional condition
$cf->create_pseudo_class_condition($ns,$value) (createPseudoClassCondition)
creates a attr condition of type pseudo class

libcontain library provides a large and growing number of fast and thread-safe containter objects written in C and C++.
The libcontain library now provides the following container types:
- a series of hash tables libcontain includes the hash table implementation from GNU glib and a hash implementation in C++ it inherited from the libhash library it originates from. This latter has been rendered thread-safe in the 0.2 release and implements a linear hashing algorithm. A single hash table implementation that will replace them both is on the drawing boards and is intended to be thread-safe and non-blocking.
- an array (vector) implementation
libcontain currently includes a non-blocking array implementation. However, this implementation presents a race-condition in concurrent calls to any of its writing functions if the array is in the process of being resized. There is currently no known non-blocking way to solve this race condition. Help is welcome in this area.
- a binomial tree
The binomial tree provided by libcontain does not provide any algorithmic logic in its implementation: it is a generic container that can be used as the basis for other container implementations, such as a heap or a map (as a matter of fact, the heap and the map are both based on this binomial tree)
- a heap
libcontain provides an automatically sorting heap implementation that (obviously) uses a heap sort to sort the elements it contains. Unfortunately, the heap implementation is not non-blocking (although bases on a non-blocking binomial tree implementation). It contains four levels of locks: a reader count and a write lock at the level of the nodes, and a reader count and a write lock at the level of the container. The locks are posed on the container for as short a time as possible so at to prevent the progress of the algorithm to block too long. If anyone knows of a non-blocking heap algorithm, input is more than welcome.
- a list
libcontain provides a non-blocking list implementation based on an algorithm by M.M. Micheal (also the inventor of Safe Memory Reclamation on which libmemory is based).
a map
The map implementation included in libcontain is based on the binomial tree implementation. Unlike some implementations based on binary trees, this implementation stores values in each node of the tree (not just the leaf nodes) and therefore allows a more memory-efficient way to store information than hashes and other map implementations. Also, the map implementation does not use a "less" function but uses a three-way comparison to compare keys (much like the helper function used by qsort). The implementation is almost (but not quite) non-blocking: for most intents and purposes, there are no real locks: read and write operations may be re-directed along a branch of the binomial tree if a node that they traverse is being deleted, but will not block for that. However, a remove operation will wait for another remove operation to finish if it traverses a node being removed.
- a queue
a non-blocking queue implementation is provided
- a stack
a non-blocking stack implementation is also provided
In future versions, the hash implementation will be replaced by a non-blocking one and the remaining problems with the existing containers will (hopefully) be solved. Help is also needed to write the architecture-dependant code for non-IA32 platforms such as Sparc.
Enhancements:
- The 0.2 release introduces number of important new features including a heap and a map, both based on a lock-free binomial tree. It also includes the required memory management to make the containters impervious to the ABA problem and thus truly thread-safe.

DBIx::Timeout is a Perl module that provides a safe method of timing out DBI requests.

The method described in the DBI documentation uses unsafe signals, which may cause memory corruption. DBIx::Timeout instead uses a separate timeout process.

The problem with using POSIX sigaction() is that it relies on unsafe signals to work. Unsafe signals are well known to cause instability. For example, imagine your DB client code is in the middle of updating some global state when the signal arrives. That global state could be left in an inconsitent state, just wait for the next time it is needed to cause problems. Since this will likely occur far from the cause, and only ocur rarely, it can be a very difficult problem to track down.

Instead, this module:

- Forks a child process which sleeps for $timeout seconds.
- Runs your long-running query in the parent process.
- If the parent process finishes first it kills the child and returns.
- If the child process wakes up it kills the parents DB thread and exits with a code so the parent knows it was timed out.

NOTE: After this call your database connection may be killed even if no timeout occurred. This is due to a race condition - the child may wake up just as parent process finishes. Patches addressing this bug are welcome. Until this is fixed you should be ready to reconnect after call_with_timeout().

Cooperative Linux is the first working free and open source method for optimally running Linux on Microsoft Windows natively.

More generally, Cooperative Linux (short-named coLinux) is a port of the Linux kernel that allows it to run cooperatively alongside another operating system on a single machine.

For instance, it allows one to freely run Linux on Windows 2000/XP, without using a commercial PC virtualization software such as VMware, in a way which is much more optimal than using any general purpose PC virtualization software.

In its current condition, it allows us to run the KNOPPIX Japanese Edition on Windows.

Mon.cgi is a CGI interface for viewing the status of a Mon service.
mon is a general-purpose scheduler and alert management tool used for monitoring service availability and triggering alerts upon failure detection. mon was designed to be open and extensible in the sense that it supports arbitrary monitoring facilities and alert methods via a common interface, all of which are easily implemented with programs in C, Perl, shell, etc., SNMP traps, and special mon traps.
mon views resource monitoring as two separate tasks: the testing of a condition, and triggering an action upon failure. mon was designed to implement the testing and action-taking tasks as separate, stand-alone programs. mon is fundamentally a scheduler which executes the monitors (each test a specific condition), and calls the appropriate alerts if the monitor fails. The decision to invoke an alert is governed by logic which offers various "squelch" features and dependencies, all of which are configurable by the user.
Monitors and alerts are not a part of the core mon server, even though the distribution comes with a handful of them to get you started. This means that if a new service needs monitoring, or if a new alert is necessary, the mon server does not need to be changed. This makes mon easily extensible.
That is from Jim Trocki who wrote mon, Im currently maintaining a web interface that works with mon which was based from Arthur K. Chans original mon.cgi.
Enhancements:
- This is the initial release of the Mon Web Interface (MWI), which is the progression of the mon.cgi Web interface.
- This interface is written entirely from scratch, with full CSS and HTML W3C complacency.
- This is an alpha release: the back end code is based on the mon.cgi tree, but the interface will have features that are currently unusable.

Diogene87 provides a scheduler system very powerfull for Linux operating systems.
Diogene87 is a powerful scheduler system for GNU/Linux. Diogene87 is a french project and is written in C.
Diogene87 provides a daemon dio87d which can be control with the dio87c communication utility. If you want to use a graphical user interface, please use Narcisse81.
Main features:
- centralized management : jobs can be run on local or remote servers (on TCP/IP network).
- jobs dependences : a job can wait for another to be terminated. A job can be started when an other is normally finished or aborted.
- start condition : a job can wait for a file-presence, for a manual validation or for a specified time.
- planning : a job can be planned at regular interval : every day, every month, every year...
- log of job activity : output of jobs (on console) are logged.
- job monitoring : a web interface is provide to control job execution.
- statistic for job duration : minimum, maximum and average duration.
- resource control : job queue with threshold for maximum number of running jobs allow to control access to limited ressources. Job queues can be manually opened or closed if the associated resource is not available.
Enhancements:
- This release provides an important bugfix: sometimes on Solaris systems, a core dump was generated when a job terminates.

Monsterz is a little arcade puzzle game, similar to the famous Bejeweled or Zookeeper.

Monsterzs goal of the game is to create rows of similar monsters, either horizontally or vertically. The only allowed move is the swap of two adjacent monsters, on the condition that it creates a row of three or more. When alignments are cleared, pieces fall from the top of the screen to fill the board again. Chain reactions earn you even more points.

This game is mostly about luck, but it remains highly addictive. You have been warned. Currently three modes are available:

Classic- play against the clock and clear a given number of each monster type to reach next level.
Puzzle- clear lines of monsters to move pieces around and put together the puzzle.
Training- play against the clock in a neverending level, chose the timer difficulty and number of monsters for infinite fun.

Monsterz is completely free software, available under the terms of the WTFPL.

AI::Prolog::Introduction Perl module contains the what and the why of logic programming.

You can skip this if you already know logic programming.

Note that most of this was pulled from my write-up about logic programming in Perl at http://www.perlmonks.org/?node_id=424075.

In Perl, generally you can append one list to another with this:

my @Z = (@X, @Y);

However, thats telling the language what to do. As sentient beings, we can look at that and infer more information. Given @Z and @X, we could infer @Y. Given just @Z, we could infer all combinations of @X and @Y that can be combined to form @Z.

Perl cannot do that. In logic programming, however, by defining what append() looks like, we get all of that other information.

In Prolog, it looks like this:

append([], X, X).
append([W|X],Y,[W|Z]) :- append(X,Y,Z).

(Theres actually often something called a "cut" after the first definition, but well keep this simple.)

What the above code says is "appending an empty list to a non-empty list yields the non-empty list." This is a boundary condition. Logic programs frequently require a careful analysis of boundary conditions to avoid infinite loops (similar to how recursive functions in Perl generally should have a terminating condition defined in them.)

The second line is where the bulk of the work gets done. In Prolog, to identify the head (first element) of a list and its tail (all elements except the first), we use the syntax [head|tail]. Since ":-" is read as "if" in Prolog, what this says if we want to concatenate (a,b,c) and (d,e,f):

Given a list with a head of W and a tail of X:

@list1 = qw/a b c/; (qw/a/ is W, the head, and qw/b c/ is X, the tail)

If its appended to list Y:

@Y = qw/d e f/;

We get a list with a head of W and a tail of Z:

@list2 = qw/a b c d e f/;

Only if X appended to Y forms Z:

X is qw/b c/. Y is qw/d e f/. Z is qw/b c d e f/.