Berkeley CSUA MOTD:Entry 29466
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2025/07/08 [General] UID:1000 Activity:popular
7/8     

2003/8/26 [Computer/Networking, Computer/SW/OS/FreeBSD, Computer/HW/Drives] UID:29466 Activity:kinda low
8/25    Do people actually verify md5 sums?  I recently ftped a linux
        distribution iso and installed it.  It seems to run fine.  Then
        by chance I run md5sum on the image and the first disk failed.
        Is this just some transmission error or something more sinister?
        \_ freebsd ports do this automatically.  You should probably try
           pulling the image again and rechecking.  it could be truly sinister,
           it could just make your system unstable down the line.  look at it
           as a strong litmus test.
           \_ I already did and the new download passed the check.  I am
                going to reinstall the whole thing.  But if it is the installer
                itself that got corrupted maliciously, should I worry about
                all the partitions of my disks and all the disks that was
                mounted when I did the installation?  That would be really
                too much pain.
                \- based on the strength [sic] of the tcp checksum
                   and the error base rate you can figure out how often
                   you can expect an undetected tranmission error.
                   we made some calculations a few years ago and when you
                   started shoveling gigabytes around you needed to start
                   worrying about these and doing some kind of stronger
                   application level checksumming. lately i havent done any
                   measurements to see if the base error rate has gone down
                   [or up say in wireless or whatever] and what the new
                   expectations might me. however i certainly am not sur-
                   prised to hear large iso or tarballs coming over long
                   paths arrived frayed at the edges. if you are interested
                   in techical details and have a general familarity with
                   tcp, you can mail me. any discussion of this on say
                   NANOG? --psb
                   \_ Google, as a result of their work, keeps track of
                      these numbers. Look up their research.
                      \- oh yeah i remember asking the google folks
                         if they do higher level checks, what chksums
                         they ue etc as the copy around parts of the
                         they use etc as the copy around parts of the
                         cache. do they "publish" these things anywhere?
                                                        --psb
2025/07/08 [General] UID:1000 Activity:popular
7/8     

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