an entertaining interactive dichotomous key...

[Dave Jefferies]

This is a lovely blast from the past. I still have the silver scroll
of a similar program I wrote nearly 20 years ago on a Sinclair ZX81
(all of 1KB RAM, tape recoder for storage, B&W TV for display and a
thermal printer) in ZX Basic. No hard drives or such luxuries and
everytime a key (or rather the plastic membrane) was pressed the
screen flickered as the computer processed the information. To
conserve memory the responses were stored in a single string with 2
character 'left' and 'right' pointers to jump from one entry to the
next.

They really don't make then like that anymore!

Dave

Doug Yanega wrote:
>
> In the spirit of it being Friday, I offer a website a friend showed me
> yesterday that demonstrates an interesting non-traditional example of an
> online dichotomous taxonomic key. The key constructs itself, in essence,
> because every time a user attempts to key out a taxon not already in the
> key, the program asks for a diagnostic feature that separates it from the
> taxon that the key *had* run to up until the point the key ended. The more
> users there are, the bigger and more complete the key becomes. The wrinkle
> is that for the key to grow, at least some of the users must already know
> the identity of their taxon (though later, obviously, other users could
> come along later and use the key without knowing, so long as they are
> competent to answer the queries). The obvious advantage to this approach is
> that the programmers do no work once the key is online - it's all built by
> the users (assuming they know the characters involved). Certainly an idea
> with potential application for purposes OTHER than that involved in this
> particular website. If you visit, you'll see what I mean... ;-)
>
> http://208.177.130.81/dictator/dictator.pl
>
> Enjoy,
>
> Doug Yanega        Dept. of Entomology         Entomology Research Museum
> Univ. of California - Riverside, Riverside, CA 92521
> phone: (909) 787-4315 (standard disclaimer: opinions are mine, not UCR's)
>            http://entmuseum9.ucr.edu/staff/yanega.html
>   "There are some enterprises in which a careful disorderliness
>         is the true method" - Herman Melville, Moby Dick, Chap. 82

--
Dave Jefferies
Sheffield Hallam University
d.w.jefferies at shu.ac.uk
0114 2253757