ZMODEM is a file transfer protocol with error checking and crash recovery. It was developed by Chuck Forsberg . Its transfer rate is similar to YMODEM-G. Like YMODEM-G, ZMODEM does not wait for positive acknowledgement after each block is sent, but rather sends blocks in rapid succession. If a ZMODEM transfer is cancelled or interrupted for any reason, the transfer can be resurrected later and the previously transferred information need not be resent.