Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!world!decwrl!sgi!shinobu!odin!nelson
From: nelson@sgi.com (Nelson Bolyard)
Newsgroups: comp.binaries.ibm.pc.d
Subject: Re: Looking for LOGO
Summary: Ladybug is available
Keywords: LOGO Ladybug
Message-ID: <1991Jan5.040106.26512@odin.corp.sgi.com>
Date: 5 Jan 91 04:01:06 GMT
References: <2782c4ba-6dacomp.binaries.ibm.pc.d@vpnet.chi.il.us> <1991Jan4.012130.23060@ariel.unm.edu>
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Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 67

In article <1991Jan4.012130.23060@ariel.unm.edu> kgowen@cie.uoregon.edu 
(Kevin Gowen) writes:
>
>Does a shareware/PD msdos implementation of LOGO exist, and if so, is there
>an ftp site I can grab it from?  I want to get my son started on learning
>basic computer stuff.
>
>You can post here or e-mail.  Thanks.
>
>-kevin
>kgowen@cie.uoregon.edu

There is a shareware program called Ladybug that is an implementation of
LOGO for the IBM PC.  It asks you to choose CGA or monochrome graphics
(Hercules, I think).  I picked it up off a BBS in Chicago called Discovery
Place BBS a few years ago.  I believe that BBS has subsequently gone off
the air.  In its original form, it would only run on the original IBM PC.
In several places throughout the code, it would compute a checksum on the
system ROM, and if it didn't match the value coded in, Ladybug would then
throw you out to the DOS prompt.  I went trough and removed all those
checksum checks, and have been using it on my clone(s) ever since.  I tried
to give my fixed version back to Discovery Place BBS, but the phone went
unanswered when I tried.

It has only one known bug.  When a command (such as forward) causes the
turtle to draw off the screen, the turtle should move to a place off the
screen, and the line drawn should be the portion of the true line, clipped
to fit in the screen's "window".  Unfortunately, when the turtle moves off
the screen, Ladybug draws a clipped line from the starting point to some
random off screen location, so it is necessary to ensure that the turtle
never goes off the screen to get good looking results.

I have found that this bug is more serious that you might think.  Children
can get very excited about seeing their creations come to life on the
screen.  But if and when the program does the right thing, it is very
discouraging, and if Daddy can't make it right, kids may give up!

There are umpteen variations on LOGO, and this is yet another.  I have
found that it is close enough to the Commodore 64 LOGO that I have been
able to use Workbooks for C64 LOGO to teach Logo to my children.  Ladybug
comes with a set of ".BUG" files that contain lots of Logo words (routines).
Ladybug is the most LISP-like version of LOGO that I've seen, which IMHO
is a good thing.

I am convinced that LOGO is the right first language for children of all
ages.  One gets immediate feedback from an interpretive language, and its
graphical nature is much more interesting than text for children.  Its
highly structured nature is perfect for teaching good programming approaches
to beginners.  (enough religion here).

No support for this software is available from the author.  I believe it
was subsequently turned into one of the expensive commercial products.
The author says that a "contribution of $35 dollars would be appreciated"
but doesn't demand it, so I wouldn't feel bad about posting it to CBIP.
I don't know if our moderator would accept it (perhaps he can write me and
tell me).

I am willing to make a .ZIP file containing Ladybug and all the .BUG files
and mail a uuencoded version to any requestors.  If I get more than about
ten requests, I'll seriously try to send it to CBIP instead of mailing out
zillions of copies.  Send e-mail to one of the addresses in my signature
below.

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Nelson Bolyard      nelson@sgi.COM      {decwrl,sun}!sgi!whizzer!nelson
Disclaimer: Views expressed herein do not represent the views of my employer.
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