Re: How to reconstitute Computist posts?

[The Wizard of Oz <wizard@emeraldcity.gov>]

On Mon, 16 May 2005 14:06:22 +0000, Greg Buchner wrote:

> In article <pan.2005.05.15.19.57.51.579994@emeraldcity.gov>,
>  The Wizard of Oz <wizard@emeraldcity.gov> wrote:
> 
>> If you take a look at the posts directly you will see they are all in 7
>> bit ASCII. In simple terms all the characters you can type in at the
>> keyboard minus the control characters and the extended characters you can
>> get with the alt key and keypad. Depending on the computer you are using
>> there may be a couple of additional characters like the vbar and backtick.
>> There was a program for the Apple// called Binscii which did pretty much
>> the same thing. Which is to say they all took a file consisting of bytes
>> (8 bits) and converted them to standard ASCII (7 bits). Uuencode did a
>> straight conversion. I think Binscii had some error checking. Finally yenc
>> added compression. The merits of compression can be good in some cases
>> (eg. raw data) or bad in others (eg. already compressed files).
>> Compressing a compressed file ends up with a larger file than the original
>> in 99% of all cases.
> 
> I don't believe yEnc does any compression.  What yEnc does is take 
> advantage of the fact that most news servers can handle 8-bit data and 
> that you can transfer binaries that way except for a few characters such 
> as linefeed and CR, which have to be 'escaped' out.  This leads to 
> generally only a 3-5% increase in file size as opposed to the uuencode 
> 33% increase in file size.

	The early specs for yEnc allowed for a compression scheme similar to the
ZIP compression. I haven't looked at them for a while. The compression may
have been removed from the current description. For a time there was some
debate as to the reliability of this compression feature. I gather it has
been resolved.

> An encoding scheme that does incorporate (simple) compression is binhex.  
> Files can be made smaller under that format but it's fairly rare as it 
> just uses a simple RLE compression method.

	I forgot about this one. When I do the article I'll include the above
paragraph (with your permission).

> I do a test, but the news reader I'm currently using will extract yEnc 
> postings, but doesn't seem to post in yEnc.  And there's a few programs 
> that will decode yEnc on the Mac OS X end, but I didn't find any that 
> would encode and let me test.

	Most readers only allow posting in plain text. To post very large files,
I gather there are special posting programs. In some of the anime
newsgroups, I have noticed a number of people with Macs. I didn't notice
if they were posting text messages or binaries.

> There is a proposed extension to yEnc which incorporates it into MIME 
> with compression added.  It's called gZip-8Bit but from the www.yenc.org 
> page it doesn't look like anythings been done with it in a while.

	This could be the one I was thinking of. It's interesting gZip is already
available to *NIX users. Mixed with tar (Tape ARchive) it's already in
common usage. Adding a compression like this to yEnc has dubious benefits
to say the least. As I said, it may end up making the resulting file
larger than the original.

> Greg B.

				Later
				Mike