GT.M supports input and output processing with the following system components:

GT.M input/output processing is device-independent. Copying information from one device to another is accomplished without reformatting.

GT.M has special terminal-handling facilities. GT.M performs combined QIO operations to enhance terminal performance. The terminal control facilities that GT.M provides include escape sequences, control character traps, and echo suppression.

GT.M supports RMS sequential disk files that are accessed using a variety of deviceparameters.

GT.M supports block I/O with fixed and variable length records for file-structured (FILES-11) tapes and non-file-structured unlabeled (FOREIGN) tapes. GT.M supports the ASCII character set for unlabeled FOREIGN and FILES-11 tapes. GT.M supports the EBCDIC character set for FOREIGN tapes only. GT.M also supports FOREIGN DOS-11 and ANSI labelled tapes or stream format records. It also supports ASCII and EBCDIC character sets.

GT.M uses permanent or temporary mailboxes fifos for interprocess communication. GT.M treats mailboxes as record-structured I/O devices.

GT.M provides the ability to direct output to a null device. This is an efficient way to discard unwanted output.

GT.M provides device-exception processing so that I/O exception handling need not be combined with process-related exception conditions. The OPEN, USE, and CLOSE EXCEPTION parameters define an XECUTE string as an error handler for an I/O device.