Xref: utzoo comp.unix.questions:28470 comp.lang.perl:3883 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!oliveb!veritas!amdcad!dgcad!dg-rtp!hunt From: hunt@dg-rtp.rtp.dg.com (Greg Hunt) Newsgroups: comp.unix.questions,comp.lang.perl Subject: Re: Need help with error correction. Keywords: error-correction Message-ID: <1991Feb6.142829.20725@dg-rtp.dg.com> Date: 6 Feb 91 14:28:29 GMT References: Sender: usenet@dg-rtp.dg.com (Usenet Administration) Reply-To: hunt@dg-rtp.rtp.dg.com Organization: Data General Corp., Research Triangle Park, NC Lines: 29 In article , steve@gapos.bt.co.uk (Steve Rooke) writes: > I have two sites, one sending a file, the other receiving. There is a lot > of corruption at the receiving end caused by line noise. I am not able to > use any standard form of error correction on the line but I can request > retransmission of the file, as many times as needed, over another link. > > I need to be able to compair these files and reconstruct the original with > reasonable confidence. By that I mean that if two, or more, files have the > same text at a certain point then I am reasonably confident that the text > is OK. > > Has anyone tried to do this sort of thing before and how did you do it, > please? Solutions based upon diff would do, I guess, for a majority of > the time. When I've had file transmission problems, I've used sum(1) to produce a checksum of the file on both the sending side machine and the receiving side machine and compared the results. If they weren't the same, then I knew that something got corrupted in the transmission and I got the file again. If the systems you're working with have sum(1) that might be an easy thing to use. Also, sum(1) will work for any sort of file, it doesn't just have to be text (which is the only thing diff(1) can look at). -- Greg Hunt Internet: hunt@dg-rtp.rtp.dg.com DG/UX Kernel Development UUCP: {world}!mcnc!rti!dg-rtp!hunt Data General Corporation Research Triangle Park, NC, USA These opinions are mine, not DG's.