Specifications
106
ELECTRONICS Australia, October, 1984
CHALLENGER
at about $400 each.
The operating system of the
Challenger is a version of MS-DOS 2.1
which differs slightly from both PC-DOS
and the MS-DOS versions used by other
IBM compatible computers. Exact
differences are detailed in the
accompanying tables, but as we shall see
they do not affect the range of programs
which can be run on the Challenger.
Compatibility
Compatibility is a vexed question. For
copyright reasons, no computer from
another manufacturer can be 100%
compatible with the IBM PC. Most
competitors in the PC market design
computers which can use standard IBM
programs, then add extra features to
offset IBM's marketing advantages.
Standard programs are those written to
run under the MS-DOS operating
system, using documented operating
system calls. They do not use features
which are peculiar to a particular
machine. In this sense the Challenger is
compatible with the IBM PC. Programs
tested by this writer include the
WordStar and Spellbinder word
processors, the Lotus 1-2-3 integrated
database, spreadsheet and graphics
program, and the dBase II database
management system. All worked as
advertised.
Compatibility with "non-standard" PC
programs is another matter. Some
programs available for the IBM PC use
the computer's internal control software
directly, making calls to the ROM BIOS
(Basic Input Output System). This
method of writing programs is not
recommended, as it usually means that
the programs cannot be transferred
easily to different machines. The famous
"Flight Simulator" program from
Microsoft is one example. In order to
speed up the presentation of graphics on
the screen, Flight Simulator directly
accesses the video display circuits of the
IBM PC. Many so-called "compatible"
computers use different display
hardware, and connot run the Flight
Simulator program. The Challenger does
not have this problem.
The extras
In addition to colour graphics the
Challenger comes with a parallel printer
connection and a serial communications
port built in, as mentioned above.
Connections for a light pen (for pointing
at the screen) and a joystick are also
standard rather than optional, but there
are no details in the manuals supplied for
the system unit or expansion unit.
Documentation is one of the poorest
features of the Challenger.
Although it runs at the same
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array which can be copied to new screen
locations with the PUT statement.
The screen displays of the Challenger
are well up to the standard expected of a
computer in this class, although low-cost
video monitors may be unable to
produce a legible 80 character text
display. This is a limitation of the video
display unit, not the computer. If a
domestic television receiver is used as the
display device, best results will be
obtained with the 40 column text mode.
Unlike the IBM PC, the Challenger
provides both monochrome and colour
graphics displays as standard. The
equivalent of IBM's colour graphics
adapter board is already built-in to the
Challenger so no extra-cost options need
to be purchased.
Software included
Programs for the Challenger are
included in the price. A ROM-based
version of Basic A is included in the
system unit while the expansion unit
comes with the essential Disk Operating
System, or DOS, full Basic A and the
"Perfect" series of word processing.
Spreadsheet and database management
programs are also supplied. Bought
separately, these three programs alone
would cost around $1,600, while IBM
charges an extra $74 for PC-DOS and
Basic A, with business programs starting