Joined: 22 Apr 2006 Posts: 6258 Location: Mumbai, India
From the manuals:
PDS A data set in direct access storage that is divided into partitions, called members, each of which can contain a program, part of a program, or data.
PDSE:A system-managed data set that contains an indexed directory and members that are similar to the directory and members of partitioned data sets. A PDSE can be used instead of a partitioned data set.
Library is rather general term, can have following definitions:
a) A collection of functions, calls, subroutines, or other data.
b) A named area on disk that can contain programs and related information (not files). A library consists of different sections, called library members.
c) A data file that contains copies of a number of individual files and control information that allows them to be accessed individually.
d) A collection of related files. For example, one line of an invoice may form an item, a complete invoice may form a file, the collection of inventory control files may a file, the collection of inventory control files may form a library, and the libraries used by an organization are known as its data bank.
e) A repository for demountable recorded media, such asmagnetic disk packs and magnetic tapes.
f) The set of publications for a product.
g) In the AS/400 system, a system object that serves as a directory to ther objects. A library groups related objects, and allows the user to find objects by name.