Create a Services class. With a Services extension you can extend TYPO3 (or an extension which use Services) with functionality, without any changes to the code which use that service.
Title:
Description:
Service type: Enter here the key to define which type of service this should be. Examples: "textExtract", "metaExtract".
Sub type(s) (comma list): Possible subtypes are defined by the service type. You have read the service type documentation. Example: using subtypes for file types (doc, txt, pdf, ...) the service might work for.
Priority: 50 = medium priority. The priority of services can be changed by admin configuration.
Quality: The numbering of the quality is defined by the service type. You have read the service type documentation. The default quality range is 0-100.
Operating System dependency:
External program(s) (comma list): Program(s) needed to run this service (eg. "perl").