The recent thread discussing W0IYH's new book got me researching Mathcad
version differences and availability of add-ons; I found essentially nothing
on the 'net that summarizes versions differences and suspect that reading
the release notes from each version would be required to do the job.
Has anyone seen such an analysis?

I have version 4.0, and from reading archived newsgroup posts it seems
that 4.0 and 5.0 were highly regarded, with increasing complaints arising
after 6.0. Worksheet (.mcd) file formats were ascii until 7.0, and evidently
more recent versions are xml based (do these no longer use a binary file
format?) I would like to continue to use 4.0, and I also appreciate that
this version is unencumbered with intrusive protection schemes (I choose
tools that are designed to work for me and not against me), doesn't need
a mysterious installation procedure (just execute the product from its
target directory), and has a small footprint but is not memory constrained.
Has anyone ever documented the ascii worksheet file format (which could
permit a re-writing of later version files to be backward compatible with
earlier versions within the constraints of common features)?

Does anyone happen to have the DSP "function pack" compatible with 4.0?
As described in advertising literature that came with my version, it offers
some excellent filter design tools that would provide interactivity missing
from the tools that I've been using, and I would enjoy trying them

Michael