If anyone creates a patch for rollback, I'll be your first tester ;)
Justin Piszcz wrote: > I was curious if lftp or wget will ever support a rollback feature and > somehow verify the bytes are correct somehow where the file has been > resumed. > > Why? This is stated below: > > LFTP VS WGET EXPERIMENT: > > PROBLEM: With lftp, many of my downloads get corrupted. > This is because the connection between my satellite link, and > my ISP > gets severed, therefore causing FTP to resume. Regular > connection > breaks are normal on a satellite connection, they may only last > 1ms or > less, however, they cause the FTP to resume, thus causing > corruption. > > QUESTION: However, does lftp corrupt files more often than say wget? > > TEST LFTP: With each 700MB pull with lftp, 6% of files usually are bad. > This means 3 to 4 re-downloads. I've downloaded over 1 > terrabyte > of data, the average seems to be about 6%, the more resumes, > the > greater the percentage file problems. > > TEST WGET: First 700MB file transfer: 0.00% corruption. > Second 700MB file transfer: 0.00% corruption. > Third 700MB file transfer: 5.00% corruption. > After several more 700MB pulls, it is about the same. > > POINT: It is a single character error. I've done multiple splits and > diffs. > I've found only 1 character is different from the original. > This is however, catastrophic for binary files.
