inaccuracies and ambiguities, making it difficult to implement from scratch. Nevertheless, the protocol came into widespread use because Punter released the source code for the original implementation into the public domain. C1 could transmit block sizes up to 255 bytes with a recommended (but not enforced) minimum of 40 bytes and an overhead of 7 bytes per block. It is optimized for transferring files stored by 8-bit Commodore computers, whose DOS treats executable and sequential files identically. Multi-Punter The term Multi-Punter can refer to any one of three or four mutually incompatible third-party variants of C1 which permit batch-file transfers, as opposed to C1, which was designed for single-file transfers. One such variant, C2, also known simply as Punter, was developed by Punter. As with C1, it is optimized for transferring files stored by 8-bit Commodore computers. Another variant was developed by Alan Peters. External links Steve Punter's original C1 specification C1 specification with interpretive annotations Punter program for IBM PC systems Notes on implementing C1 and Peters' Multi-Punter Thread discussing the details of the protocol Modern description/analysis of the Punter protocol BBS file transfer protocols Commodore 64