Re: How to reconstitute Computist posts?

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

On Sat, 14 May 2005 20:59:10 -0400, Martin Doherty wrote:

> Mike,
> 
> Would you mind posting a quick idiot's guide on how to turn your 
> postings on cba2 back into their original forms for viewing?
> 
> I have no idea what YENC is. As Schultz said, "I KNOW NOTHING!"
> 
> Martin

	This isn't a "me too" post detailing the same information as the other
followups. I'll add some background so you can see the need for yenc or
uuenccode.

	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.

	Now the question is why the conversion to 7 bits in the first place.
Traditionally the newsgroups have been for text only. Pictures, sounds,
and programs were frowned upon as a waste of space. That's what ftp was
for. Now that storage and bandwidth costs have dropped, the "rules" have
been relaxed for some "binaries" groups. Additionally there were older
computer systems on the net (and presumably still are) which were 7 bit
computers. These were usually mainframes. I can't think of any 7 bit
micros. Some of these 7 bit machines did not handle 8 bit posts
gracefully. Considering the way the internet works is by passing data from
one machine to another, there may be problems with the 7 bit
machines mangling the 8 bit posts (I actually ran across this a few
times). Therefore a need came about for programs to convert from 8 bits to
7 bits and back.

	As an aside, sometimes the data gets mangled in transmission. I have
encountered this too. Occasionally the person posting will also post a
checksum for verification. More recently there has been a program called
"par" and the newer "par2" which will allow the person downloading the
data to reconstruct the file(s). It usually involves a larger download,
but the odds of getting a complete file the first time rise immensely.

	Now on to what to do with the 7 bit posts... There are a couple or three
methods of dealing with this. It all depends on which resources you have
available and which platform you are working with. The first method is
quite a bit of work and should work on most platforms. This is to download
all the 7 bit posts, strip the headers, combine the files, and run a
program to decode the resulting file. I've done this with Binscii and
UUEncode on my GS as well as a DOS PC. I've been told this works on Macs
too. From this point on the Apple// is excluded from the solutions. When I
was using M$ (I have since seen the light) I found Netscape was able to
decode and display small files in the newsreader. If the file was large
enough to result in a multi-part post then Netscape wouldn't handle it.
For pictures I was able to do a "save as" with no problem. The best
solution at this time is to get a newsreader which can handle the larger
files. The majority allow the user to post to the groups as well but there
are some exceptions. Some ISPs deliberately mangle some very large posts
(eg. video files). Granted this isn't the case here, however for the sake
of completeness I figure I'd talk about it. There are programs which will
"aggregate" the contents of many servers simultaneously so the user can
construct a complete file even though there are parts missing from
different servers. The theory is each server will be missing different
parts. Some of these programs will appear in the form of a read only
newsreader (eg. BNR2) or a pseudo-server (eg. Newsplex or Leafnode).

	As to which programs to use... Others have made good suggestions. I don't
use M$ any more so my suggestions would be out of date. However as a *NIX
user I have found both M$ and Mac ports to some very good Linux programs.
Although there are commercial programs out there, sometimes the free ones
are more than adequate to the task. It's a matter of trying them out to
determine which one works best for you. If you can't find something free
which suits your needs then you should look for something which allows a
demo period before you buy. I've had friends go the non-demo commercial
route immediately and ended up with the free programs anyhow.

	I hope this gives you some background...

	Hmmm... This looks good enough to turn into an article. With your
permission I'd like to copy and paste this response. It should appear in
the July issue of Call-A.P.P.L.E.. We are considering making this a free
issue (Advertisers are welcome). BTW, Bill says he is putting together the
May issue right now.

				Later
				Mike (a different one)