What is Xmodem?

Xmodem meaning An asynchronous file transfer protocol initially developed for CP/M personal computers. First versions used a checksum to detect errors. Later versions use the more effective CRC method. Programs typically include both methods and drop back to checksum if CRC is not present at the other end. Xmodem transmits 128 byte blocks. Xmodem-1K improves speed by transmitting 1024 byte blocks. Xmodem-1K-G transmits without acknowledgment [for error free channels or when modems are self correcting], but transmission is cancelled upon any error. Contrast with Kermit, Ymodem, Zmodem.


reference: U.S . Food & Drug – Glossary of Computer System Software Development Terminology (8/95)