X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f996b,637bed96a2434e5a X-Google-Attributes: gidf996b,public X-Google-ArrivalTime: 1994-06-16 14:02:04 PST Path: nntp.gmd.de!xlink.net!howland.reston.ans.net!swrinde!emory!nntp.msstate.edu!olivea!news.hal.COM!decwrl!waikato!canterbury.ac.nz!equinox.gen.nz!equinox!Colin_Douthwaite Subject: Re: TALK: xxdecode Newsgroups: alt.ascii-art References: <9406070356.AA19108@davinci.icad.puc-rio.br> X-Newsreader: TIN [version 1.2 PL3] From: Colin_Douthwaite@equinox.gen.nz (Colin Douthwaite) Message-ID: Date: Fri, 17 Jun 94 06:55:20 +1200 Organization: Equinox Networks Lines: 69 Winston Smith (winston@merk.com) wrote: : On Wednesday, June 8, 1994 at 07:09:53 GMT (1:09am EDT ?) : paul@heino.ibh.rwth-aachen.de (Paul Foerster) writes: : PF> ... I never heard of xxencode. So let's generate some questions from : PF> scratch: : : I can think of a very good reason for XXENCODE, namely that the first, : and fastest hardware on the computer networks are typically IBM mainframes : which run the EBCDIC character set (a.k.a. translation tables for Hollerith : punchcard strings). As a result, files in the big networks are constantly : "pouring through" EBCDIC IBM mainframes at the large academic and : industrial sites. [...Winston Smith's treatise on XX encoding omitted...] Well I'm not sure about the contents of your treatise but here is what Richard Marks, author of the UU/XX Encoder/Decoder has to say about UU and XX encoding systems: ------------------------------------------------------------------- [ EXTRACT FROM: Richard Marks UUENCODE/DECODE Documentation File ] UU-encoding is a way to code a file which may contain any characters into a standard character set that can be reliably sent over diverse networks. Another newer less popular encoding method, called XX-encoding uses the set: +-01..89ABC...XYZabc...xyz In my opinion, XX-encoding is superior to UU-encoding because it uses more "normal" characters that are less likely to get corrupted. In fact several of the special characters in the UU set do not get thru an EBCDIC to ASCII translation correctly. Conversely, an advantage of the UU set is that it does not use lower case characters. Now-a-days both upper and lower case are sent with no problems; maybe in the communications dark ages, there was a problem with lower case. A third encode mapping is the one used by Brad Templeton's ABE program. This is not handled by these programs as the check and control information surrounding the actual encoded data is in a different form. [ end of extract ] ************************************* Q. What does the acronym XX mean ? ************************************* "XX" is not an acronym. It is a name for a variation of the UUencode program. I guess the writer just chose the "XX" letters and the name stuck. The "XX" and "UU" programs are identical except that "UU" maps into one set of ASCII characters and "XX" uses another mapping; except for the mapping tables, the programs are identical. The "XX" mapping is superior now. -------------------------------------------------------------------- Bye,