\chapter{RT-11 Operating Characteristics} \label{RT-11 Operating Characteristics} \section{Startup} TECO is started with the \begin{verbatim} .R TECO \end{verbatim} command. TECO is now immediately ready to accept commands. The text buffer and Q-register areas are empty. The EDIT command \begin{verbatim} .EDIT/TECO filespec \end{verbatim} is used to edit an already existing file. It is equivalent to \begin{verbatim} .R TECO *EBfilespec`Y`` \end{verbatim} For those RT-11 users that will use TECO as the primary editor, a monitor {\tt SET} command is provided: \begin{verbatim} .SET EDITOR TECO \end{verbatim} Once this command is issued, the {\tt /TECO} option on the {\tt EDIT} command is no longer necessary since the default editor is now TECO. Since this {\tt SET} command only has affect between system bootstraps, it is recommended that the command be placed in the appropriate startup file (e.g., {\tt STARTS.COM}). Now, assuming the {\tt SET} command has been issued, the command \begin{verbatim} .EDIT filespec \end{verbatim} can be used to edit an already existing file. The standard RT-11 {\tt EDIT} command options are all available with TECO. \begin{verbatim} .EDIT/CREATE filespec .EDIT/INSPECT filespec .EDIT/OUTPUT:filespec filespec \end{verbatim} Another option, {\tt /EXECUTE}, is also available: \begin{verbatim} .EDIT/EXECUTE[:string] filespec \end{verbatim} The {\tt /EXECUTE} option causes TECO to process the filespec (assumed {\tt .TEC} filetype) as a set of TECO commands. If {\tt string} is used, the string is placed into TECO's text buffer. If {\tt string} contains only alphanumeric characters, it does not have to be enclosed in quotes. If it is to contain blanks, it must be quoted with single quotes. The equivalent TECO commands would be \begin{verbatim} .R TECO *ERfilespec`YHXZHKIstring`MZ`` \end{verbatim} Note the input file remains open and can provide more input to the macro. \section{File Specification} The file access commands {\tt ER}, {\tt EB}, {\tt EI}, and {\tt EW} accept a file specification in the standard RT-11 format: \begin{verbatim} dev:filename.type \end{verbatim} in which dev: is a physical device name or a user assigned logical name; if {\tt dev:} is not specified, the default {\tt DK:} is assumed. The filename field must be specified in the commands {\tt ER}, {\tt EB}, {\tt EI}, and {\tt EW} and be a legal RT-11 filename. The type field is a file extension and must be explicitly given if used (there is no default). The {\tt EB} and {\tt EW} commands also accept the extended notation for an output file size \begin{verbatim} dev:filename.type[n] \end{verbatim} The optional {\tt [n]} specifies the output file size where {\tt n} is the number of blocks to be allocated. \section{Backup Files} The {\tt EB} command maintains one level of file backup on RT-11. The pre-edited input file name is changed to \begin{verbatim} filename.BAK \end{verbatim} before the new output file is closed with the original name. Only normal file closing commands ({\tt EC}, {\tt EF}, {\tt EG}, and {\tt EX}) cause this renaming to happen. If TECO is aborted or the output file is purged by the {\tt EK} command, the input filename remains unchanged. Note only one {\tt .BAK} file for a given name is kept; earlier {\tt .BAK} backup files are deleted each time a new backup file is created. A good policy to follow when editing is to close the edited file frequently enough so that an unexpected incident would not cause a substantial loss of work. Files should be backed up regularly. TECO has the power to let an unsuspecting user alter a good file into a completely useless state. The {\tt SRCCOM} program can be used to verify an editing session. \section{Exit And Go} If TECO is exited via the {\tt EGstring}\escape command, the string is passed to the system as the next command to execute. This string may be any valid command or an indirect command file specification. \section{Reenter And Close} \label{Reenter And Close} The RT-11 {\tt REENTER} command may always be used to continue TECO. Its primary differences from running TECO is that when {\tt REENTER} is used, the text buffer and Q-register areas are unmodified, as opposed to when TECO is run the text buffer and Q-register areas are cleared. The input and output file are always lost upon reentering TECO. If an output file was open before reentering TECO, the file will have to be recreated with the appropriate {\tt E}-command. (Note that the monitor commands {\tt GT ON}, {\tt GT OFF}, {\tt LOAD}, and {\tt UNLOAD} disallow a {\tt REENTER}.) The output file is not closed if TECO is aborted. The RT-11 {\tt CLOSE} command can be used to make the output file permanent, but be aware that the output file will not be complete because of internal buffers that TECO keeps. TECO may be reentered after a {\tt CLOSE} command. \section{File Recovery} TECO can be a useful tool in recovering ASCII files lost on a block replaceable device. TECO allows block replaceable devices to be opened in a non-file structured mode. This gives the user the capability to open a disk and access ASCII data anywhere on it, independent of file boundaries. The command \begin{verbatim} ERdev:` \end{verbatim} is used to open the device at which point {\tt \_} (underscore or backarrow) searches may be used to locate specific ASCII data and transfer it to new output files. Note that files tend to get reproduced, in whole or part, many places on a block replaceable device; be sure to verify that any given text is indeed complete and the correct version. \section{System Crash Recovery} \label{System Crash Recovery} TECO and RT-11 are highly reliable, but if during an important edit session a random system failure should occur, the following procedure may help save some or all of the editing. \begin{enumerate} \item Bootstrap the system \item Immediately perform a {\tt SAVE} command to save as much of memory as possible into a file on {\tt SY:}. The address range form of the {\tt SAVE} command must be used. The {\tt SAVE} command will not allow any part of the monitor to be saved, e.g., if you have a 28K system and are running {\tt SJ} you cannot save 28K but only 26.3K. \item Perform standard startup procedures, e.g., {\tt DATE}. \item Use TECO on the {\tt SAVE}d file to try and recover useful parts of the edit. \end{enumerate} \section{VT11 Graphics Support} \label{VT11 Graphics Support} If the monitor supports the VT11 graphics processor ({\tt GT ON} and {\tt GT OFF} work) TECO will automatically start up in display mode, adjusting to both the size of the display screen and to the presence or absence of the scroller. If the display fails to start with a working VT11, TECO has decided that there is not enough free memory and will not allocate the display file buffer or start the display. See Section \ref{Scope Commands} for a description of the available commands to interact with the display. Various aspects of the display screen become immediately obvious upon seeing them; the text pointer, its position and shape and its position between lines; wrap around of more than 72 characters per line; the scroller interaction and so on. Experiment with a scratch file for more familiarity.