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tehmaze-labs / modem

XMODEM, YMODEM and ZMODEM implementations in Python
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ymodem.py initial packet composition error #9

Open ApiumJacob opened 2 years ago

ApiumJacob commented 2 years ago

If I send a simple file called "hello.txt" using a program that I know has a working y-modem send protocol to another program that I know has a working y-modem receive program data transfer looks like (blue = sender, green = receiver, ymodem-ul is the command to start the receiver): image

The initial packet payload consists of the filename + 0x00 + filesize + 0x00 padding.

The ymodem.py program is not adding the file size to the initial packet which is causing my receiver to reject the packet:

image

I'm not sure if either programs that I know work are compliant to the standard and the files size may be optional.

The checksum of the initial packet from ymodem.py does seem to be being calculated correctly. image

ApiumJacob commented 2 years ago

I see that this issue is addressed in pull request https://github.com/tehmaze-labs/modem/pull/2