In a recent note, Gerhard Postpischil said: > Date: Mon, 26 Jun 2006 21:23:50 -0400 > > Paul Gilmartin wrote: > > In a recent note, Rick Fochtman said: > >> I've learned that my compression algorithm can create records longer > >> than > >>the original records, so I'm working on a fix for that, as well. > > There's no fix for that (think Pigeonhole Principle). You must be > > prepared to tolerate it. > > There is a proof somewhere (Knuth?) to the effect that for every record > that's compressible, there's one that will be longer. Empirically I ran > Pigeonhole principle, AKA Dirichlet's Principle.
> across this in the seventies with Wylbur, which replaced repeated blanks > by a single character, and inserted a count byte every sixteen > non-blanks. Later versions of Wylbur used a flag bit in the record to > indicate it wasn't compressed. Perhaps something similar could be used > in ARCHIVER (I haven't looked at the source in some decades). > Ah, but how do you add the flag bit without making the record at least one bit longer? -- gil -- StorageTek INFORMATION made POWERFUL ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
