If a pseudo-device, pipe, or character special file is connected for formatted or unformatted sequential access with no RECL= specifier, the default record length is 32 768 rather than 2 147 483 647, which is the default for sequential-access files connected to random-access devices.
In certain cases, the default maximum record length for formatted files is larger, to accommodate programs that write long records to standard output. If a unit is connected to a terminal for formatted sequential access and there is no explicit RECL= qualifier in the OPEN statement, the program uses a maximum record length of 2 147 483 646 (2**32-2) bytes, rather than the usual default of 32 768 bytes. When the maximum record length is larger, formatted I/O has one restriction: WRITE statements that use the T or TL edit descriptors must not write more than 32 768 bytes. This is because the unit's internal buffer is flushed each 32 768 bytes, and the T or TL edit descriptors will not be able to move back past this boundary.