World CDEV
Volume Number: 5
Issue Number: 9
Column Tag: System Sleuthing
Related Info: Script Manager
World CDEV Investigated 
By Martin Minow, Mike Carleton, Arlington, MA
Note: Source code files accompanying article are located on MacTech CD-ROM orsource code disks.
Sleuthing the Map Cdev
[Martin Minow is a Principal Engineer at Digital Equipment Corporation.
Originally a speech major (later a linguist), he decided he might need a “real” job
someday, so he took the last programming course given for the Illiac I computer in
1962. When his graduate study grant ran out, he joined Digital Equipment
Corporation in 1972, where he has held positions in software support and speech
research and development, eventually working on the DECtalk speech synthesizer. He
is currently a Principal Engineer in the mid-range system’s advanced development
group. In his spare time, he runs marathons (slowly), and orienteers (even more
slowly).
Mike Carleton received his BSEE in 1981. He first worked on special purpose
compiler systems used to test the black boxes in fighter aircraft. After joining Digital
Equipment Corporation in 1984 he supported the TOPS-10/20 COBOL compiler.
Later he joined up as the system engineer for the VAX Supercomputer Gateway product
and worked hand in hand with Cray Research engineers to make their two systems talk
to each other. Currently, he is a Senior Software Engineer at Digital Equipment
Corporation.]
System 6.0 includes an unexpected gimmick--a control panel program that
displays a world map and allows you to select your location and time zone. The system
is distributed with about 80 large cities already defined, and it is very easy to add your
own location. However, there doesn’t appear to be any published way to extract the
information for your own applications.
With a little poking around, we were able to decipher the internal information
and think that other MacTutor readers might find it useful. By using the code in the
following program, your phase of the moon program (or program to determine sunrise
and sunset times) need not ask the user to specify the system’s location.
The program has only been tested on Mac SE’s and Mac II’s under System 6.0. At
its heart is a subroutine to read data from the clock parameter ram.