Free graphs for provided health care system software for linux

Fast Secure File System exports existing directories securely over the network, letting users store and retrieve encrypted data in a scalable and transparent way. FSFS is written in C and works on GNU/Linux systems on x86 and PPC architectures, with help from FUSE and OpenSSL.
File systems are easily the most evident, from the point of view of users, component of an operating system. Through file systems it is possible to organize data in a wide variety of ways, and access resources through a common interface.
Users can nowadays not only store and retrieve documents, but also find information on running processes and system settings (through ProcFS), access and manipulate e-mail (for example with GmailFS), or perform several other operations.
In several circumstances and scenarios it is desirable to protect stored files and directories from manipulation by unknown or malicious users: financial or health-related data, confidential documents, or any kind of personal or sensitive data may need to be stored securely, in such a way that it can not be examined or modified freely by third parties.
Most file systems do not take action in this sense, and external cryptographic utilities are sometimes employed to secure data before storage. While this can be a perfectly secure solution, it is not transparent to users.
Distributed file systems propose efficient ways of accessing data remotely as if it resided on the local machine; when it comes to dealing with securely stored data as in the examples above, care must be taken to preserve confidentiality and integrity also during network transfer.
Not all distributed file systems accomplish this task, weakening the overall security of the system, or do so inefficiently, making it inconvenient for users.
FSFS is a secure, distributed file system in users space, written in C with much help from FUSE and OpenSSL. It lets users store and retrieve data securely and transparently, knowing that it is protected both on permanent storage devices and while in transit over the network.
It is also concerned with scalability, therefore separates data cryptography from the server, leaving it to the clients; this approach is similar to the one used in CFS, and opposite to those taken on by other secure file system solutions (like NFS on top of IPsec).
FSFS is written as a pair of user space daemons that act as client and server. Because of this, it needs no kernel support (unlike NFS over IPsec), save the FUSE loadable kernel module on clients, included in Linux since 2.6.14; servers dont use FUSE and depend only on user space OpenSSL libraries.
Servers export an existing file system (of virtually any kind) to clients over the network through two separate channels: a TLS connection set up with OpenSSL, and a clear channel. Requests from the clients to the servers are sent via the TLS socket, thus they are encrypted and authenticated, according to TLS v1 specifications, by the channel itself and decrypted on receipt, as they are usually very short and the relevant cryptography does not constitute a great overhead; simple server replies undergo the same process.
Cryptography in this case happens at both ends of the transmission.
In a distributed file system, large amounts of data may be transferred between clients and servers, thus encrypting and decrypting everything may become too cumbersome for both parties, and as more clients are added to the system the server may severely lose performance; moreover, file data should be stored encrypted anyway, so the cryptography could be moved to the clients, in such a way that each encrypts data before a write operation sends it over the network to the server, and decrypts it after a read retrieves it.
This way servers only deal with TLS details and can concentrate on serving client requests by doing the relevant I/O on the underlying, "physical" file system. As the data is already encrypted, it does not need to go through the TLS channel and the corresponding overhead, but can be sent via the clear channel, provided the messages are authenticated.
Enhancements:
- This release fixes two bugs. One bug related to socket creation and would cause problems on some systems (namely OpenSUSE 10.2). The other bug related to server configuration creation when using the Python configuration utilities. Users dont need to upgrade to this release if theyre not experiencing problems or are not using the Python configuration utilities.

Graph::ModularDecomposition is a Perl module for modular decomposition of directed graphs.

SYNOPSIS

use Graph::ModularDecomposition qw(pairstring_to_graph tree_to_string);
my $g = new Graph::ModularDecomposition;

my $h = $g->pairstring_to_graph( ab,ac,bc );
print "yesn" if check_transitive( $h );
print "yesn" if $h->check_transitive; # same thing
my $m = $h->modular_decomposition_EGMS;
print tree_to_string( $m );

This module extends Graph::Directed by providing new methods related to modular decomposition.

The most important new method is modular_decomposition_EGMS(), which for a directed graph with n vertices finds the modular decomposition tree of the graph in O(n^2) time. Method tree_to_string() may be useful to represent the decomposition tree in a friendlier format; this needs to be explicitly imported.

If you need to decompose an undirected graph, represent it as a directed graph by adding two directed edges for each undirected edge.

The method classify() uses the modular decomposition tree to classify a directed graph as non-transitive, or for transitive digraphs, as series-parallel (linear or parallel modules only), decomposable (not series-parallel, but with at least one non-primitive module), indecomposable (primitive), decomposable but consisting of primitive or series modules only (only applies to graphs of at least 7 vertices), or unclassified (should never apply).

PHP Advanced Graphing Class is a PHP class that can be used to generate line, bar, and 2D/3D pie graphs from multiple data sets. PHP Advanced Graphing Class offers many style and data formatting options.
The graphs can be built from data defined with PHP code or with data imported from XML or CSV files. It can use custom colors, custom data point shapes or images, custom end arrows, an optional inline format, a custom graph scale, etc.
The graphs can be generated in PNG format either to a file or served as the current script output.
Enhancements:
- Bar charts and 2D/3D pie charts were added.

GraphViz is a Perl interface to the GraphViz graphing tool.

SYNOPSIS

use GraphViz;

my $g = GraphViz->new();

$g->add_node(London);
$g->add_node(Paris, label => City ofnlurve);
$g->add_node(New York);

$g->add_edge(London => Paris);
$g->add_edge(London => New York, label => Far);
$g->add_edge(Paris => London);

print $g->as_png;

This module provides an interface to layout and image generation of directed and undirected graphs in a variety of formats (PostScript, PNG, etc.) using the "dot", "neato", "twopi", "circo" and "fdp" programs from the GraphViz project (http://www.graphviz.org/ or http://www.research.att.com/sw/tools/graphviz/).

What is a graph?

A (undirected) graph is a collection of nodes linked together with edges.
A directed graph is the same as a graph, but the edges have a direction.

What is GraphViz?

This module is an interface to the GraphViz toolset (http://www.graphviz.org/). The GraphViz tools provide automatic graph layout and drawing. This module simplifies the creation of graphs and hides some of the complexity of the GraphViz module.

Laying out graphs in an aesthetically-pleasing way is a hard problem - there may be multiple ways to lay out the same graph, each with their own quirks. GraphViz luckily takes part of this hard problem and does a pretty good job in a couple of seconds for most graphs.

Why should I use this module?

Observation aids comprehension. That is a fancy way of expressing that popular faux-Chinese proverb: "a picture is worth a thousand words".
Text is not always the best way to represent anything and everything to do with a computer programs. Pictures and images are easier to assimilate than text. The ability to show a particular thing graphically can aid a great deal in comprehending what that thing really represents.

Diagrams are computationally efficient, because information can be indexed by location; they group related information in the same area. They also allow relations to be expressed between elements without labeling the elements.
A friend of mine used this to his advantage when trying to remember important dates in computer history. Instead of sitting down and trying to remember everything, he printed over a hundred posters (each with a date and event) and plastered these throughout his house. His spatial memory is still so good that asked last week (more than a year since the experiment) when Lisp was invented, he replied that it was upstairs, around the corner from the toilet, so must have been around 1958.

Spreadsheets are also a wonderfully simple graphical representation of computational models.