06 lined

This document describes LINED, a line editor for DECsystem-10 disk files.

Purpose: LINED is used to create and edit source program files stored on disk. These files are in ASCII format and include appended line sequence numbers. A key feature is its ability to reference any line at any time without requiring the user to close and reopen the file. It operates as a reentrant program, utilizing 2K pure and 2K impure core segments.

Accessing LINED:

• Users can initiate LINED via Monitor commands:

  • CREATE filename.ext: To open and edit a new disk file.
  • EDIT filename.ext: To open and edit an existing disk file.

• Alternatively, R LINED can be typed, followed by an S filename.ext command within LINED to select (or create with S filename.ext ($)) a file.

LINED Commands (in command mode, indicated by *):

• Inserting/Replacing: Innnnn (single line) or Innnnn,iiiii (multiple lines with increment iiiii). If a line exists at nnnnn, it's replaced.
• Deleting: Dnnnnn (single line) or Dmmmmm,nnnnn (range of lines).
• Printing: Pnnnnn (single line) or Pmmmmm,nnnnn (range of lines).
• Closing File: E command closes the current file and returns to LINED command mode.
• Exiting to Monitor: Typing ^C (Control-C) returns the user to the Monitor level.

Conventions and Implementation:

• Lines are stored with a 1-word header containing the sequence number and word count.
• LINED uses temporary files (###EDT.TMP, ###LIN.TMP) during editing. When closing a file, the original file is renamed with a .BAK extension for backup purposes, and the temporary output file becomes the new primary file.
• DECsystem-10 line sequence numbers are a standard format: five ASCII decimal digits, with bit 35 of the line sequence number word set to 1.
• The system includes error handling, displaying messages for issues like non-existent files, illegal commands, or system errors. Most errors return control to LINED command mode, while fatal errors return to the Monitor.