` ANTIC VOL. 2, NO. 4 / JULY 1983`

## I/O BOARD

3-D MAZE MODIFICAFIONS

3-D Maze is the best computer magazine game I've ever seen. I found a few additions very helpful, however. To eliminate the annoying possibility of a very short path to the exit, constrain the start position to be near the center of the maze:

460 X=INT(RND(0)*6+(MD-7)/2)+XM+1
462 Y=INT(RND(0)*6+(MD-7)/2)+YM+1

It s very nice at the end to be able to see the path you've traversed by pulling the joystick backwards:

653 IF STICK(0)=13 THEN GOSUB 700
654 IF STRIG(0)=1 THEN SOUND 0,RND(0)*200,10,2:GOTO 653
655 RUN

However, the score should not be penalized for doing so:

705 IF A\$(A,A)<>E\$ THEN PT=PT+10*MD
782 PT=PT+1:IF A\$(A,A)=E\$ THEN PT= INT( PT / 10) *10
783 POKE 656,0:POKE 657,23:PRINT " SCORE ";PT;

Finally, a compass is needed to orient yourself in the maze:

465 DIR=0
504 IF S=11 THEN DIR=DIR1:GOSUB 950:GOTO 515
506 IF S=7 THEN DIR=DIR+1:GOSUB 970:GOTO 515
20070 NEXT I
20080 POKE 656,1:POKE 657,34
20090 IF DIR=-1 THEN DIR=3
20100 IF DIR=4 THEN DIR=0
20110 GOSUB DIR+20410:RETURN

Bernard Oppenheim
Indianapolis, IN

My son, Brett, and I have made a few changes which allow you to pause the play by pressing any key (giving you a breather to think, and to resume play by pressing the RETURN key:

5 POKE 764,255
501 IF PEEK(764)<>255 THEN 5000
5000 SOUND 0,0,0,0
5001 IF PEEK(764)=12 THEN 504
5002 GOTO 5001

Bob Hawkins
Pittsburgh, PA

NEW BULLETIN BOARD

I have recently opened a twenty-foor hour, seven-day-a-week bulletin board in Edison, New Jersey. The bulletin board runs under TARI-BOARD, Version 1.4 and the telephone number is (201) 549-7591. Please let your readers know.

Scott Brause
Edison, NJ

There are an estimated 200 Atari-dedicated bulletin boards presently on line around the world. The May issue of ANTIC contains a comprehensive article about bulletin boards and how to use them as well as many phone numbers. -- ANTIC ED

MIFFED -- 2+

I must lodge a complaint concerning the review of FILEIT--2+ (ANTIC, June '83). The system is billed as a Financial Database System! The review says that none of the \$50 or less systems support computed fields. The FILEIT--2+ package not only supports computed fields but subtotals and monthly totals as well. The financial programs are the strongest part of FILEIT--2 +. Show me another \$50 package that can generate a report like FILEIT 2+.

Jerry White
Levittown, NY

DEGAUSSING EASTERN FRONT

In response to the May Photo Fun contest, the mystery programmer must be Chris Crawford, author of EASTERN FRONT. I noticed that he stores his disks in a flip-n-file next to his television. Isn't it bad practice to store disks so close to the television?

David Stambaugh
Washington, IL

Potential sources of magnetic disturbance should be avoided in areas where dusks and tapes are stored. Line scanning for the television picture tube is controlled by powerful magnets at the back of the tube, and in some sets a magnetic field may be generated which extends into the nearby environment. Our own experience indicates that while there may be some risk of data loss, we have yet to scramble disk files due to television set proximity, and we allow a certain casualness. Evidently Crawford, a programmer of some experience, also assumes a comfortably casual attitude.--ANTIC ED

PERCOM DOUBLE DENSITY

Readers who have purchased PERCOM double density disk drives (either single or double sided) and have been limited to using the OSA + 4.0 or OSA+ 4.1 operating system to take advantage of the double density capacity of their drives may be interested in a modification to ATARI DOS which I have written. It enables access to all ATARI DOS-compatible files in a double-density context, saves a great deal of RAM, and makes copying from single density to double density disks a breeze. Interested readers may contact me for further information.

Steve Kaufman
BJ Smartware
6507 Bracken Ridge
Cincinnati, OH 45213

REAL COMPUTERS EAT QUICHE

I am a dietician and owner of an ATARI 800 with 48K and a disk drive. Do you know of any programs dealing with dietetics -- including programs about the nutritive values of foods, recipe and portion control, food costing, and menu planning?

Beverly Peiss
Oak Park, MI

In the March issue of ANTIC we printed a query about the availability of genealogy software and suggested that readers who knew of such material should write to I/O Board. The response was excellent, and in the May issue we passed these software references on to our readers.

If you, our readers, know of Atari-compatible software which deals with food, menu planning, calorie counting or pricing, please let I/O Board know about it. We will compile a summary list and pass the information back to you in a future issue. --ANTIC ED

LEGAL OR ILLEGAL

I recently purchased the Assembler Editor cartridge for my ATARI, along with the book, The Atari Assembler, which has helped me a lot in learning Assembly Language. The book uses the Operating System (OS) subroutine at \$F6A4 to print characters to the screen, and mentions that there are many such useful subroutines available in the OS. It would be very helpful if you could name other subroutines.

Paul Shaw (age 14)
San Rafael, CA

The Put Character subroutine that you mention is not a legal Atari ROM vector. Programs that enter the OS at other than officially prescribed locations may not be compatible with future OS upgrades. Much of the software on the 1200XL suffers from this problem. More on this in the future. --ANTIC ED

BREAK AND SYSTEM RESET

I would like to know how to disable the BREAK and the SYSTEM RESET keys. I am 13 years old and am creating many programs to sell. I would like to prevent consumers from breaking into or altering my programs.

John Trapani
Staten Island, NY

There are many methods and techniques used to "protect" programs. Disabling the BREAK key and forcing SYSTEM RESET to cold start the computer are simple tricks which you can apply to make it difficult for users to LIST your program or accidentally stop its execution as an autorun disk. Beware, however, as users can still LOAD the program and LIST it using DOS! POKE 53774,64 and POKE 16,64 (the shadow register) to disable the BREAK key (do this again after every GRAPHICS mode command). POKE 580,1 to make the computer automatically coldstart when SYSTEM RESET us pressed.--ANTIC ED

800 VS. 5200

As an Atari computer owner, I enjoy the superb graphics of Atari games. If the 5200 advanced game system is really an Atari computer, can I use game cartridges for the 5200 in my computer?

Chris White
Gretna, LA

No. They don't fit. But more, while similar graphics display technologies are used both in the 400/800 computers and in the 5200 video computer system, there are some major hardware and software differences (such as what happens with joystick signals, essential ingredients to most games). We would suggest that you not run the 5200 cartrudge through your band saw, to make it fit your computer cartridge slot. --ANTIC ED