Unix-Based Authoring Systems

[Bruce Sherwood]

I am responding to a request for information about Unix-based authoring systems.

Here in the Center for Design of Educational Computing (CDEC) at Carnegie Mellon
University, we have created the cT programming environment (formerly called CMU
Tutor) which runs on Unix workstations, regular Macs, and MS-DOS PCs.  In fact,
programs written in cT run on all these environments WITHOUT CHANGE, despite the
use of sophisticated modern user interface elements such as menus, graphics,
multi-font text, etc.  Displays adjust themselves to fit the screen or window
size available.  While cT is a general-purpose programming environment, it
contains many features of great utility in writing educational software, as a
descendant of the Tutor and MicroTutor languages developed in the PLATO project
at the University of Illinois.  Already some cT programs have won national
awards in the EDUCOM/NCRIPTAL educational software competition.  The cT language
has also been used for research computing tasks.

For several years cT has been in use at CMU and other universities, running on
the old Andrew "wm" window manager on IBM RTs, Suns, and VaxStations.  That
window manager is no longer available, so we are in the process of making cT run
on X11.  This work is nearly complete, and we hope within a couple months to
make it generally available for these machines.  CMU will only sell site
licenses, for a particular machine, and the price will be $4000 commercial,
$2500 educational (upgrades will be $1500 commercial and $1000 educational).

CMU began distributing the Mac version 1.0 last summer, but starting next month
version 1.1 for both the Mac and the PC will be available from Falcon Software,
P.O. Box 200, Wentworth NH 03282 (phone 603-764-5788).  The CMU price for the
Mac version was $92.50, but Falcon hasn't yet set a price.

Here is some more info about cT:

The cT Programming Language and Environment

General Description

The cT programming language (formerly known as CMU Tutor) makes it feasible even
for non-expert programmers to produce interactive programs which exploit modern
computer capabilities such as graphics, multi-font text, and mouse inputs.  The
cT language offers special enhancements for educational software; it is also
used for research computing tasks.  (cT is a trademark of Carnegie Mellon
University.)

Programs written in the cT language can be compiled and run WITHOUT CHANGE on a
wide range of machines, which is nearly without precedent for programs with
modern user interfaces.

Major features of the cT language include

interactive graphics in windowed environments
instant portability across diverse computers
automatic rescaling of text and graphics to fit the window
multi-font text
menus
mouse and keyset inputs
analysis of words and sentences
analysis of numbers and algebraic expressions
rich sequencing options
standard calculational capabilities
numeric and text files

Major features of the cT programming environment include

integrated editing and execution environment
incremental compilation for fast revision and execution
on-line reference manual with executable examples
graphics editor which generates cT graphics statements
accurate and informative error diagnostics

The package includes the programming environment, introductory text, reference
manual, on-line reference manual, sample programs, and a freely distributable
run-time package.  The programming environment is licensed for single users but
is not copy-protected.  The run-time package may be freely copied, so that
authors of cT programs can distribute this package with binaries of their
programs, without having to pay additional license fees.


System requirements for Mac:  Macintosh Plus, Macintosh SE, or Macintosh II with
1 Mbyte of memory.  Hard disk recommended, or two 800 K floppy disk drives.

System requirements for the initial PC offering:  640K MS-DOS, EGA or VGA,
mouse.  Numerical coprocessor recommended.  Hard disk recommended, or 1.2MB
floppy drive.