croes@fwi.uva.nl (Felix A. Croes) (11/08/90)
Hi, I keep having zmodem problems with the new rs232 driver. The problem occurs if I am receiving a file from a remote machine. After receiving 1K correctly, the second and successing blocks have to be received at least twice. When zmodem switches to very small blocks the problems still occur - this never happened to me before, no matter how bad the line was. It happens with ANY file, ALWAYS after succesfully receiving the first block. The fact that the first block is received correctly and the varied error messages of zmodem seem to suggest a buffering problem (note that when receiving from this particular remote machine, data is only received and nothing is send back except in the case of an error). The problems occur with any modem speed, however. Sometimes things seem to be allright again - for about 1K, then there follows another wave of errors. Does anybody else have the same problems? Does anybody know how to solve them? Regards, Felix Croes -- Felix Croes (croes@fwi.uva.nl)
croes@fwi.uva.nl (Felix A. Croes) (11/08/90)
croes@fwi.uva.nl (Felix A. Croes) writes: [...] > The fact that the first block is received correctly and the varied error >messages of zmodem seem to suggest a buffering problem (note that when receiving >from this particular remote machine, data is only received and nothing is send >back except in the case of an error). The problems occur with any modem speed, >however. I did some more tests - it is indeed a buffering problem. When running programs that produce large amounts of text in a continuous stream, pieces disappear. -- Felix Croes (croes@fwi.uva.nl)
croes@fwi.uva.nl (Felix A. Croes) (11/09/90)
croes@fwi.uva.nl (Felix A. Croes) writes: >[...] >> The fact that the first block is received correctly and the varied error >>messages of zmodem seem to suggest a buffering problem (note that when receiving >>from this particular remote machine, data is only received and nothing is send >>back except in the case of an error). The problems occur with any modem speed, >>however. I have found the problem, or rather I have found where it isn't: not in Minix. I reverted to 1.5.10, which had always worked fine, to do some tests, and the same problems occurred. Appearently it is either caused by the phone connection or the remote machine. It seems that extensively testing two different connections to four different machines with customized private communication software on the remote machine (for protection against friendly super users installing wonderful new versions) was not careful enough. At least now I know exactly how the tty driver works :-) -- Felix Croes (croes@fwi.uva.nl)