# Sequential Files > [HTML Version](sequentialfiles.htm) __ Sequential file (aka stream) notes: • Typically text-oriented, but may consist of raw binary data as well. • Byte, field, or line-oriented. • May contain variable length fields and lines, or simply be a stream of bytes. • Open for input or output, but not both at the same time, except for the terminal. • The terminal screen and keyboard are two special sequential files, implicitly opened for input and output, respectively, on channel #0. • Record locking not supported. • Serial ports may be accessed as sequential files. • TCP sockets may be also be accessed as sequential files; see [MX\_FILESOCK](mx_filesock.htm.md). • Output files grow automatically via PRINT. • Access is by default sequential but 'cursor' can be repositioned using [MX\_FILEPOS](mx_filepos.htm.md) **Subtopics** - [OPEN](opensequential.htm.md) - [INPUT](input_seq.htm.md) - [PRINT](printstatement.htm.md) - [WRITECD](writecd.htm.md)