Writing Real Programs in DCL, Second Edition
A complete how-to guide for programming in DCL for the OpenVMS operating system.
TABLE OF CONTENTS Writing Real Programs in DCL, Second Edition
Chapter 13: Files and Directories
Overview
THIS CHAPTER BEGINS THE DISCUSSION of OpenVMS files. A file is a collection of information stored on some physical medium, such as magnetic disk or magnetic tape. All permanent information available to an OpenVMS system and its applications ultimately resides in files, so every OpenVMS programmer must understand files. This understanding is even more critical for DCL programmers because DCL applications are often centered on the manipulation of files and their contents.
13.1 File Specifications
A file specification is a character string that identifies an individual file or set of files on a OpenVMS system. A similar kind of specification can also be used to name a device or a disk directory, without reference to any particular files. In this book, the term file spec refers to all manner of device, directory, and file specifications, even though some do not identify individual files.
The format of a file spec was reviewed in Chapter 1, but it will be presented here in greater detail. A complete OpenVMS file spec has the following format:
node::device:[directory ] name.type;version
13.1.1 Node
The node component serves to specify a file on a particular DECnet or IP node. The name of the node is included in the spec, followed by a double colon to distinguish it from a device name. Multiple nodes can be included, each one followed by a double colon. In this case, the final node names the location of the file, with preceding nodes specifying the network path to be...
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