Vcr Plus Coder/DeCoder

(text file for VCRPLUS.ARC)

This programme generates (or codes) and analyses (or decodes) VCR+
codes for shows that start and end on the hour or half hour and are no
more than five hours in length.

VCR+ is the encrypted coding for the VCR+ module... these are the
codes for the Gemstar VCR_Plus device as they appear in, say,
TV Guide.

If you want the coding for a show which is NOT printed, you can, of
course, call their 900- phone number, or generate you own with this.

Apparently a computer science/math teacher gave a college class the
problem of breaking the VCR+ coding... a C-programme resulted (posted
on the InterNet?) which wound up on GEnie as a ZIP file. After some
trouble (most of the users could not understand why an Atari 8 bitter
would want the file, for he could not run such sophisticated code), I
got a listed copy of the programme. I analysed the algorithm and
recoded from scratch (the coding algorithm here is much better than
the original... the original algorithm, on an 8088, could take up to a
minute to code... in interpretted turbo basic, mine takes a few
seconds).

A listed version of the programme was made available to a Commodore 64
programmer (who was intrumental in getting me a text copy of the
C-programme) and has been converted to the C-64. His version was then
converted to the AppleII.

The programme is in TurboBasic (there are versions of Turbo that work
with Sparta3.2d and on 800 systems).

The archive contains a title screen (AUTORUN.BAS) along with the
programme (VCRPLUS.TRB) and the full description of the algorithm (for
six or fewer digit VCR+ codes... that is, those for shows
starting/ending on hours or half-hours, and of no more than five hours
duration).

You may want to modify it to input the shows to convert from a disk
file, say, instead of typing them in separately.

This programme (based upon the algorithms I got from GEnie) is
freeware... that is, I wrote it (so don't take credit for it and I am
the copyright holder) but you are free to share this with any and all
other Atari 8 bitters who show interest in it.

                                        John McGowan
                                        jmcgowan@bigcat.missouri.edu