Questions Beginners Ask
Tom R Halfhill,
Are you thinking about buying a
computer for the first time, but don't know anything about computers?
Or maybe you just purchased a computer and are still a bit baffled.
Each month in this column, COMPUTE!
will tackle some questions that we
are asked by beginners.
Q When the new Atari 1200XL computer was
announced a few months ago, Atari said it would be "software
compatible" with the older Atari 400 and 800 models. Doesn't this mean
that software which worked on the 400/800 should also work on the
1200XL? Then why won't certain cartridges for the 400/800 fit into the
1200XL's cartridge slot?
A To be fair, this
isn't Atari's fault. But before we get to the cartridge question, let's
define exactly what is meant by "software compatible," since this
question is coming up frequently, too. And this definition applies to
all computers, not just Ataris.
Atari 400/800 software is upward compatible with the
new 1200XL. This means that programs written properly for the 400/800
also will run on the 1200XL - although the reverse is not necessarily
true. If a program is specifically written to take advantage of the
1200XL's special features (such as the HELP or special function keys,
or the 64K of memory), it probably won't work on the 400/800 unless
adjustments are made.
But note that we said "properly written" software.
Some programmers take shortcuts which can cause compatibility problems.
Usually these shortcuts involve what are known as "illegal calls" to
the computer's operating system. The operating system is a built-in
program in all computers which does routine "housekeeping" tasks
necessary to a computer's operation. Machine language programmers
sometimes "call" routines built into the operating system to save
themselves the trouble of writing similar routines. This is perfectly
okay, except that these calls must adhere to certain rules to insure
that the program will work on all future versions of the operating
system. Atari's operating system manuals state that if these rules are
obeyed, future compatibility is assured.
That's why some machine language programs won't run
on all versions of Ataris - the programmer took an unauthorized
shortcut. Several popular commercial games were affected in this way
when Atari revised the 400/800 operating system about a year ago.
Late-model 400/800s have a "Revision B" operating system which fixes a
few bugs in the old one. The changes were subtle, but some programs
which depended on the old operating system were rendered unworkable.
The 1200XL has a somewhat different operating system
than the 400/800. Among other things, it includes the 1200XL's built-in
diagnostics. Machine language programs for the 400/800 which call the
operating system properly should have no trouble running on the new
Now, as for the cartridges: it's true that some
Atari 400/800 cartridges made by independent software companies will
not fit the 1200XL's slot. However, all cartridges made by Atari do
fit. The slots are identical, except that the 1200XL has less room
around the opening (the 1200XL's slot is external, while the 400/800
slot is beneath the front hatch). Some independent software companies
made their cartridges oversized, which is why they won't fit a new slot.
Probably these companies will issue new versions to
fit the 1200XL. If you recently bought an oversized cartridge for a
1200XL, you may be able to exchange it. If you can't, the only solution
is to take apart the cartridge. The "cartridge" is really just a
protective plastic housing around a small circuit board. One screw or
some glue usually holds it together. When the housing is removed, the
board can be plugged into the slot. But do this only as a last resort,
because it involves two dangers: (1) Exposed circuit boards are
delicate and easily damaged by mishandling, and (2) if you accidentally
manage to plug in the board upside-down, the board can be ruined. If
you take apart a cartridge, we recommend clearly marking which side
goes up (or forward in a 400/ 800), and fashioning some sort of
protective cover out of cardboard or a flexible plastic cassette tape
Q I heard that Commodore recently introduced
a new model computer called the "VIC-21," and that it is already being
sold in some cities. What is the VIC-21? Why didn't we read about it
ahead of time?
A Not to worry, we
didn't let you down. There is really no such thing as a VIC-21- even
though a store in Boston started selling them a few months ago.
Confused? So were a lot of Bostonians. What happened
is that a store began advertising a sale on the "VIC-21," which was
really just an ordinary VIC-20 with a 16K memory expansion cartridge
included. The package sold for about $200. As a promotion, the store
pasted stickers on the boxes which said "VIC-21" - apparently derived
from the sum of 16K plus the VIC's built-in 5K of memory. When people
started calling competing stores and Commodore about the "new
computer," Commodore immediately disavowed any connection with the
promotion. Although it has been hinted that someday Commodore may
upgrade the standard VIC, possibly with 16K, no such plans have been