I know this won't work, I just want to know -why-.

Another crackpot thought pattern from me. I occasionally poke my head
into this group and rattle off some inane, but unusual thought
regarding compression methods. I understand the basic concepts of
compression, and I get the whole "you can't get something for nothing"
line of reasoning, but I still like thinking towards the more exotic
forms of data compression.

Anyway, recently, I found myself reasoning thusly:

It is possible, nay trivial, to create redundancy data for any file
which will detect and correct any error up to the size of the
redundancy data. Simple, yes?

Why, therefore, would it be impossible to take a file, create just over
50% redundancy for it, delete the original file, create a -completely
random- file of exactly the same size, and apply the recovery data to
the random file? Statistically, only about half of the bits should be
wrong. Also, you're not compressing N-bytes into fewer than N-bytes,
since the random file is N-bytes, and the recovery data is 1/2 * N
bytes.

I suspect that my misunderstanding here lies in my understanding of
error detection and recovery, but I just wanted to make sure.

.

Relevant Pages

  • Re: I know this wont work, I just want to know -why-.
    ... > compression, and I get the whole "you can't get something for nothing" ... > It is possible, nay trivial, to create redundancy data for any file ... > random- file of exactly the same size, and apply the recovery data to ... Also, you're not compressing N-bytes into fewer than N-bytes, ...
    (comp.compression)
  • Re: [opensuse] Backup Process
    ... but I don't know of a tool that can record removable media compressed with recovery data designed to bypass the common types of media errors. ... I'm not talking of state of the art maximum compression: ... No on the fly compression with error recovery data, and on the fly recovery, tailored for the backup media. ...
    (SuSE)
  • Re: [opensuse] Backup Process
    ... Did you ever use the old PCBackup for Dos, from PC Tools? ... The technology is out there somewhere, but I don't know of a tool that can record removable media compressed with recovery data designed to bypass the common types of media errors. ... I'm not talking of state of the art maximum compression: ...
    (SuSE)
  • Re: [opensuse] Backup Process
    ... rsync could ... Compression is good until you get an erroneous bit. ... They are compressed, yes, but they also contain recovery data to ... The other items mentioned are all either command-line or scripted. ...
    (SuSE)