User`s guide

Specifying Files
You specify files by using a name of one to six alphanumeric characters (followed,
optionally, by a period and a file type of up to three alphanumeric characters). No
spaces or tabs are allowed in the file name or file type.
The file type generally indicates the format or contents of a file; and it is good practice
to conform to the standard file types for RT–11.
If you do not specify a file type for an input or output file, most system programs use
or assign an appropriate default file type. You can modify the default file types for
some utilities, using the software customization described in the RT–11 Installation
Guide.
Table 3–3 lists the standard file types used in RT–11.
Table 3–3: Standard File Types
Type Meaning
ANS SYSGEN answer file
BAC Compiled BASIC–PLUS program
BAD Files with bad (unreadable) blocks; you can assign this file type whenever
bad areas occur on a device. The BAD file type makes the file permanent
in that area, preventing other files from using it and consequently becoming
unreadable. A BAD file cannot be moved by SQUEEZE.
BAK Editor backup file
BAS BASIC–PLUS source file (BASIC–PLUS input)
BAT BATCH command file
BLD Command file to execute SYSGEN monitor (MON) and device handler (DEV)
build files
BOT A magtape boot file
BUP Backup utility program output file
C PDP–11 C source file (C input)
CMD PDP–11 C command file
CND SYSGEN conditional file
COM DCL command file, IND control file, or SIPP command file
CRF Cross-reference listing file
CTL BATCH control file generated by BATCH compiler
CTT BATCH internal temporary file
DAT BASIC, FORTRAN, or IND data file
DBL DIBOL source file
Using Files, Volumes, and Devices 3–7