 | |
| Developer(s) | Tx0 <tx0@strumentiresistenti.org> |
|---|---|
| Stable release | 0.6 |
| Written in | C |
| Operating system | Linux kernel |
| Available in | English |
| Type | Semantic file system |
| License | GNU GPL |
| Website | http://www.tagsistant.net/ |
| Developer(s) | Tx0 |
|---|
Tagsistant is a semantic file system for the Linux kernel, written in C and based on FUSE. Unlike traditional file systems that use hierarchies of directories to locate objects, Tagsistant introduces the concept of tags.
In computing, a file system is a type of data store which could be used to store, retrieve and update files. Each file can be uniquely located by its path. The user must know the path in advance to access a file and the path does not necessarily include any information about the content of the file.
Tagsistant uses a complementary approach based on tags. The user can create a set of tags and apply those tags to files, directories and other objects (devices, pipes, ...). The user can then search all the objects that match a subset of tags, called a query. This kind of approach is well suited for managing user contents like pictures, audio recordings, movies and text documents but is incompatible with system files (like libraries, commands and configurations) where the univocity of the path is a security requirement to prevent the access to a wrong content.
A Tagsistant file system features four main directories:
Tags are created as sub directories of the tags/ directory and can be used in queries complying to this syntax:
tags/subquery/[+/subquery/[+/subquery/]]/@/ [1] where a subquery is an unlimited list of tags, concatenated as directories:
tag1/tag2/tag3/.../tagN/The portion of a path delimited by tags/ and @/ is the actual query. The +/ operator joins the results of different sub-queries in one single list. The @/ operator ends the query.
To be returned as a result of the following query:
tags/t1/t2/+/t1/t4/@/an object must be tagged as both t1/ and t2/ or as both t1/ and t4/. Any object tagged as t2/ or t4/, but not as t1/ will not be retrieved.
The query syntax deliberately violates the POSIX file system semantics by allowing a path token to be a descendant of itself, like in tags/t1/t2/+/t1/t4/@ where t1/ appears twice. As a consequence a recursive scan of a Tagsistant file system will exit with an error or endlessly loop, as done by UNIX find :
~/tagsistant_mountpoint$findtags/ tags/ tags/document tags/document/+ tags/document/+/document tags/document/+/document/+ tags/document/+/document/+/document tags/document/+/document/+/document/+ [...]This drawback is balanced by the possibility to list the tags inside a query in any order. The query tags/t1/t2/@/ is completely equivalent to tags/t2/t1/@/ and tags/t1/+/t2/t3/@/ is equivalent to tags/t2/t3/+/t1/@/.
The @/ element has the precise purpose of restoring the POSIX semantics: the path tags/t1/@/directory/ refers to a traditional directory and a recursive scan of this path will properly perform.
Tagsistant features a simple reasoner which expands the results of a query by including objects tagged with related tags. A relation between two tags can be established inside the relations/ directory following a three level pattern:
relations/tag1/rel/tag2/The rel element can be includes or is_equivalent. To include the rock tag in the music tag, the UNIX command mkdir can be used:
mkdir -p relations/music/includes/rockThe reasoner can recursively resolve relations, allowing the creation of complex structures:
mkdir -p relations/music/includes/rockmkdir -p relations/rock/includes/hard_rockmkdir -p relations/rock/includes/grungemkdir -p relations/rock/includes/heavy_metalmkdir -p relations/heavy_metal/includes/speed_metalThe web of relations created inside the relations/ directory constitutes a basic form of ontology.
Tagsistant features an autotagging plugin stack which gets called when a file or a symlink is written. [2] Each plugin is called if its declared MIME type matches
The list of working plugins released with Tagsistant 0.6 is limited to:
<title> and <keywords> elements and with document, webpage and html tooEach Tagsistant file system has a corresponding repository containing an archive/ directory where the objects are actually saved and a tags.sql file holding tagging information as an SQLite database. If the MySQL database engine was specified with the --db argument, the tags.sql file will be empty. Another file named repository.ini is a GLib ini store with the repository configuration. [3]
Tagsistant 0.6 is compatible with the MySQL and Sqlite dialects of SQL for tag reasoning and tagging resolution. While porting its logic to other SQL dialects is possible, differences in basic constructs (especially the INTERSECT SQL keyword) must be considered.
The archive/ directory has been introduced to provide a quick way to access objects without using tags. Objects are listed with their inode number prefixed. [4]
The stats/ directory features some read-only files containing usage statistics. A file configuration holds both compile time information and current repository configuration.
It has been highlighted that relying on an external database to store tags and tagging information could cause the complete loss of metadata if the database gets corrupted. [5]
It has been highlighted that using a flat namespace tends to overcrowd the tags/ directory. [6] This could be mitigated introducing triple tags.
Apache Subversion is a version control system distributed as open source under the Apache License. Software developers use Subversion to maintain current and historical versions of files such as source code, web pages, and documentation. Its goal is to be a mostly compatible successor to the widely used Concurrent Versions System (CVS).
Trac is an open-source, web-based project management and bug tracking system. It has been adopted by a variety of organizations for use as a bug tracking system for both free and open-source software and proprietary projects and products. Trac integrates with major version control systems including Subversion and Git. Trac is used, among others, by Django, FFmpeg, WebKit, 0 A.D., and WordPress.
The SQL SELECT statement returns a result set of rows, from one or more tables.
Maven is a build automation tool used primarily for Java projects. Maven can also be used to build and manage projects written in C#, Ruby, Scala, and other languages. The Maven project is hosted by The Apache Software Foundation, where it was formerly part of the Jakarta Project.
In Unix-like operating systems, find is a command-line utility that locates files based on some user-specified criteria and either prints the pathname of each matched object or, if another action is requested, performs that action on each matched object.
The following tables compare general and technical information for a number of relational database management systems. Please see the individual products' articles for further information. Unless otherwise specified in footnotes, comparisons are based on the stable versions without any add-ons, extensions or external programs.
Bacula is an open-source, enterprise-level computer backup system for heterogeneous networks. It is designed to automate backup tasks that had often required intervention from a systems administrator or computer operator.
QGIS is a geographic information system (GIS) software that is free and open-source. QGIS supports Windows, macOS, and Linux. It supports viewing, editing, printing, and analysis of geospatial data in a range of data formats. QGIS was previously also known as Quantum GIS.
Gadfly is a relational database management system written in Python. Gadfly is a collection of Python modules that provides relational database functionality entirely implemented in Python. It supports a subset of the standard RDBMS Structured Query Language (SQL).
NTFS links are the abstraction used in the NTFS file system—the default file system for all Microsoft Windows versions belonging to the Windows NT family—to associate pathnames and certain kinds of metadata, with entries in the NTFS Master File Table (MFT). NTFS broadly adopts a pattern akin to typical Unix file systems in the way it stores and references file data and metadata; the most significant difference is that in NTFS, the MFT "takes the place of" inodes, fulfilling most of the functions which inodes fulfill in a typical Unix filesystem.
Serendipity is a blog and web-based content management system written in PHP and available under a BSD license. It supports PostgreSQL, MySQL, SQLite database backends, the Smarty template engine, and a plugin architecture for user contributed modifications.
A document-oriented database, or document store, is a computer program and data storage system designed for storing, retrieving and managing document-oriented information, also known as semi-structured data.
A hierarchical query is a type of SQL query that handles hierarchical model data. They are special cases of more general recursive fixpoint queries, which compute transitive closures.
Apache Empire-db is a Java library that provides a high level object-oriented API for accessing relational database management systems (RDBMS) through JDBC. Apache Empire-db is open source and provided under the Apache License 2.0 from the Apache Software Foundation.
TACTIC is a web-based, open source workflow platform and digital asset management system supported by Southpaw Technology in Toronto, ON. Designed to optimize busy production environments with high volumes of content traffic, TACTIC applies business or workflow logic to combined database and file system management. Using elements of digital asset management, production asset management and workflow management, TACTIC tracks the creation and development of digital assets through production pipelines. TACTIC is available under both commercial and open-source licenses, and also as a hosted cloud service through Amazon Web Services Marketplace.
The following is provided as an overview of and topical guide to databases:
Oracle NoSQL Database is a NoSQL-type distributed key-value database from Oracle Corporation. It provides transactional semantics for data manipulation, horizontal scalability, and simple administration and monitoring.
Autopsy is a computer program that performs forensic searches of computer storage volumes. It is maintained by Basis Technology Corp. and community programmers. Basis Technology Corp. sells support services and training for the program.
Database Workbench is a software application for development and administration of multiple relational databases using SQL, with interoperationality between different database systems, developed by Upscene Productions.
The syntax of the SQL programming language is defined and maintained by ISO/IEC SC 32 as part of ISO/IEC 9075. This standard is not freely available. Despite the existence of the standard, SQL code is not completely portable among different database systems without adjustments.
