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Re: Re: What's in the " .mb" files????

  • Subject: [mg2629] Re: [mg2579] Re: What's in the " .mb" files????
  • From: ross at ("Ross Moore <ross at>")
  • Date: Thu, 30 Nov 1995 21:00:23 -0500
  • Approved:
  • Distribution: local
  • Newsgroups: wri.mathgroup
  • Organization: Wolfram Research, Inc.

Dave Wagner replied recently as follows...

>In article <DIECnt.MHG at>,
>J.P. and/or Valerie Purswell <purswell at> wrote:
>>Must be a lot of information that's not directly viewable in these files.  Can 
>>someone give me an idea as to what exactly is stored in these files and why 
>>mma puts information  it needs to evalaute a notebook in a different file?  
>The .mb files contain the information in the .ma file but in binary form,
>which enables a notebook file to be opened faster.  To my knowledge,
>there shouldn't be any info in the .mb that isn't recoverable from the .ma,
>and you should be able to freely delete those files if they're taking up
>too much space, at the price of slower opening of your .ma files.
>I can't believe that deleting a .mb would change the active/inactive
>status of any cells, because when you transmit a notebook to another
>platform, all that gets sent is the .ma file.

What Dave says seems to be applicable in the Unix world with the 
X-Front End, but NOT necessarily so under DOS/Windows.

I have had students prepare notebooks on their home PCs.
When these notebooks are ftp'd to Unix (or Macintosh), along with
the .mb files (as binary data), the graphics are NOT recoverable.
Instead they have to be re-generated from the code, (which hopefully
is all still there in the  .ma  file).

Thus there IS INDEED information in the .mb file (under DOS) that
IS NOT recoverable from the  .ma  file.

My conclusion has been that  .mb files have a different purpose
under DOS than under Unix, and are NOT transportable.

Obviously this is not the ideal situation. 
I would like to be wrong on this matter; 
but my experiences indicate otherwise.

Would someone from WRI please clarify what IS the real situation.
Or WAS...
 ... if this has been fixed already with the latest version
of the DOS/Windows Front End. What version of the Student Edition
should students be advised to purchase in order to avoid such problems 
in future?

A separate issue concerning the  .mb  files under Unix.
Such files seem to grow interminably, retaining (?) old 
renderings when a graphics cell is re-generated after a small
change (of ViewPoint, say).

This leads to long delays in saving the notebook.
It is not unknown for the huge .mb file to become corrupted.
Students with limited quotas (under unix) can be severely

I find it advisable to occasionally close the Notebook and
delete the .mb file. Upon re-opening the Notebook the retained
graphics must be re-rendered, of course. 

This is using version 2.2.2 of the kernel, 
with associated XFE Version 2.2. (c) 1993



Ross Moore                         Internet: ross at
Mathematics Department                Work:       +61 2 850-8955
Macquarie University                   Home:   please do not try
North Ryde, Sydney                     Fax:       +61 2 850-8114
Australia  2109

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