Battle in the B-Ring

The idea for this game came from an article in Analog -- Science Fiction/Science Fact Magazine (no relation to ANALOG Computing). The article, entitled Blivit in the B-Ring, was written by Richard C. Hoagland. In it, Hoagland presented facts and speculation about an object in Saturn's B-Ring that had cleared a hundred-meter gap between the rings. Several explanations for this phenomenon were presented, such as a tiny, primordial black hole or an extraterrestrial artifact. For purposes of this game, I chose the latter.

Typing it in.

Before typing anything, look at the listings accompanying this article.

Listing 1 is the BASIC data and data checking routine. This listing is used to create both cassette and disk versions of Battle in the B-Ring. The data statements are listed in hexadecimal (base 16), so the program will fit in 16K cassette systems. This makes typing more difficult, but it's a necessary evil.
Listing 2 is the assembly-language source code for Battle in the B-Ring, created with the OSS MAC/65 assembler. You do not have to type this listing to play the game! It is included for those readers interested in assembly language.

Follow the instructions below to make either a cassette or disk version of Battle in the B-Ring.

Cassette instructions.

Type Listing 1 into your computer using the BASIC cartridge, and verify your typing with C:CHECK (see page 21).
Type RUN and press RETURN. The program will begin and ask:
```
MAKE CASSETTE (0) OR DISK (1)?
```
Type 0 and press RETURN. The program will checking the DATA statements, printing the line number of each as it goes. It will alert you if it finds any problems. Fix any incorrect lines and re-RUN the program if necessary, until all errors are eliminated.
When all DATA lines are correct, the computer will beep twice and prompt you to "READY CASSETTE AND PRESS RETURN." Insert a blank cassette in you recorder, press the RECORD and PLAY buttons simultaneously and hit RETURN. The message "WRITING FILE" will appear, and the program will create a machine-language boot tape version of Battle in the B-Ring, printing each DATA line number as it goes. When the READY prompt appears, the game is recorded and ready to play. CSAVE the BASIC program onto a separate tape before continuing.
To play the game, rewind the tape created by the BASIC program to the beginning. Turn your computer OFF and remove all cartridges. Press the PLAY button on your recorder and turn ON your computer while holding down the START key. If you have a 600 or 800 XL computer, you must hold the START and OPTION keys when you turn on the power. The computer will "beep" once. Hit the RETURN key and Battle in the B-Ring will load and run automatically.

Disk instructions.

Type Listing 1 into your computer using the BASIC cartridge, and verify your typing with D:CHECK2 (see page 21).
Type RUN and press RETURN. The program will ask:
```
MAKE CASSETTE (0) OR DISK (1)?
```
Type 1 and press RETURN. The program will begin checking the DATA statements, printing the line number of each as it goes. It will alert you if it finds any problems. Fix any incorrect lines and re-RUN the program if necessary, until all errors are eliminated.
When all DATA lines are correct, you will be prompted to "INSERT DATA [sic] WITH DOS, PRESS RETURN." Put a disk containing DOS 2.0S into drive #1 and press RETURN. The message "WRITING FILE" will appear and the program will create an AUTORUN.SYS file on the disk, displaying each DATA line number as it goes. When the READY prompt appears, the game is ready to play. Be sure the BASIC program is SAVED before continuing.
To play the game, insert the disk containing the AUTORUN.SYS file into drive #1. Turn your computer OFF, remove all cartridges and turn the computer back ON. Battle in the B-Ring will load and run automatically.

The game.

In the B-Ring of Saturn, a huge extraterrestrial artifact has been discovered. It is a Bussard ramjet of alien manufacture; a huge, hydrogen-gulping behemoth that has traveled between stars and is now orbiting, dormant, around our sixth planet. The two most powerful nations on earth have launched missions to retrieve the alien vessel and study its advanced technology. Neither side wishes to share the prize, so a battle is inevitable.

To play the game, plug joysticks into ports one and two. Once the program has been loaded, the menu will appear. Pressing the OPTION key will highlight the game selection (collisions, ring density, ring speed). Pressing the SELECT key will choose the particular variation (non-scoring or scoring collisions; low, medium or high density rings; and slow or fast ring speed). Pressing START returns you to the game screen, where gameplay is initiated by pressing the joystick trigger button. Pressing any of the three console buttons during gameplay returns you to the menu.

There are many dangers in Saturn's rings. You must avoid collisions with the chunks of rocks and ice that constitute the rings themselves, and the electrical discharges that randomly arc across the gap. You should also be aware that the artifact is still active and will fire its missiles at anything in its path.

Player movements are controlled by the joysticks. Your missiles are fired by pressing your trigger button. Each player may have only one missile on screen at a time. Missile directions, either left or right, are controlled by the computer. Player destruction occurs when your saucer has suffered a total of ten collisions with missiles or ring debris. Collision counters appear at the bottom of the screen. If the non-scoring option is used, collisions with ring debris do not count. Contacts with the white-hot nozzle of the artifact or the electrical discharges are instantly fatal. Colliding with the opposing player's saucer results in the destruction of both players.

To win the game, you must hit the rocket nozzle of the artifact with one of your missiles. The artifact will stop, and the nozzle will begin to cool. Once it has cooled you must dock your saucer with it. If the other player has been destroyed you have won, and the game is over. If not, then you're a sitting duck. You can neither fire nor retreat while docked, but your opponent retains his mobility, It's either him or you! Only one person can rescue the alien ship!

Listing 1: BASIC Listing

10 REM *** BATTLE IN THE B RING ***
20 TRAP 20:? "MAKE CASSETTE (0), OR DI
SK (1)";:INPUT DSK:IF DSK>1 THEN 20
30 TRAP 40000:DATA 0,1,2,3,4,5,6,7,8,9
,0,0,0,0,0,0,0,10,11,12,13,14,15
40 DIM DAT$(91),HEX(22):FOR X=0 TO 22:
READ N:HEX(X)=N:NEXT X:LINE=990:RESTOR
E 1000:TRAP 120:? "CHECKING DATA"
50 LINE=LINE+10:? "LINE:";LINE:READ DA
T$:IF LEN(DAT$)<>90 THEN 220
60 DATLIN=PEEK(183)+PEEK(184)*256:IF D
ATLIN<>LINE THEN ? "LINE ";LINE;" MISS
ING!":END 
70 FOR X=1 TO 89 STEP 2:D1=ASC(DAT$(X,
X))-48:D2=ASC(DAT$(X+1,X+1))-48:BYTE=H
EX(D1)*16+HEX(D2)
80 IF PASS=2 THEN PUT #1,BYTE:NEXT X:R
EAD CHKSUM:GOTO 50
90 TOTAL=TOTAL+BYTE:IF TOTAL>999 THEN 
TOTAL=TOTAL-1000
100 NEXT X:READ CHKSUM:IF TOTAL=CHKSUM
 THEN 50
110 GOTO 220
120 IF PEEK(195)<>6 THEN 220
130 IF PASS=0 THEN 170
140 IF  NOT DSK THEN 160
150 PUT #1,224:PUT #1,2:PUT #1,225:PUT
 #1,2:PUT #1,0:PUT #1,32:CLOSE #1:END 
160 FOR X=1 TO 79:PUT #1,0:NEXT X:CLOS
E #1:END 
170 IF  NOT DSK THEN 200
180 ? "INSERT DISK WITH DOS, PRESS RET
URN";:DIM IN$(1):INPUT IN$:OPEN #1,8,0
,"D:AUTORUN.SYS"
190 PUT #1,255:PUT #1,255:PUT #1,0:PUT
 #1,32:PUT #1,136:PUT #1,45:GOTO 210
200 ? "READY CASSETTE AND PRESS RETURN
";:OPEN #1,8,128,"C:":RESTORE 230:FOR 
X=1 TO 40:READ N:PUT #1,N:NEXT X
210 ? :? "WRITING FILE":PASS=2:LINE=99
0:RESTORE 1000:TRAP 120:GOTO 50
220 ? "BAD DATA: LINE ";LINE:END 
230 DATA 0,28,216,31,255,31,169,0,141,
47,2,169,60,141,2,211,169,0,141,231,2,
133,14,169,56,141,232,2
240 DATA 133,15,169,0,133,10,169,32,13
3,11,24,96
1000 DATA D8A203BDC02A9DC402BDBC2A9DDC
06CA10F1A9008D08D2A9038D0FD24C302C48A5
CA8D04D4A92C8D0002684048,46
1010 DATA A5CC8D04D4A9398D0002684048A9
028D0AD48D01D4A9498D0002684048A5CA8D04
D4A9568D0002684048A5C98D,763
1020 DATA 04D4A91F8D00026840A901ACDD06
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1090 DATA 62E4A90885CCAD2206C90BD00FA2
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38E90D0A0A0A85CDA9CC38E5CD85CDA20018B5
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18AC0AD2C06BB0F8B1BAC900,619
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AD0AD2F0FAC969B0F685BA9D,856
1190 DATA F206A000B1BAD0EBAD0AD2290FF0
F905CE91BAAD0AD2290FF0F905CFA08091BAE8
E003D0B8A900A2129D00079D,840
1200 DATA 8007CA10F7A014AD060685BB85CF
A96B85CEE886BAB1BA91CE8810F9A014E8A5BA
18698085BA9002E6BBA5CE18,44
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B9862991BA91CE8810F6E6CF,232
1240 DATA E6CFA074A90085CEA90191CEC8C0
7CD0F9A070A9C091C2A07F91C2A203BDB82A9D
C002CA10F7A9088D04D485CA,810
1250 DATA 85CC8D1FD085C5A90985C4A9638D
2602A9208D2702A901A200A004205CE4A9A08D
2802A9208D2902A902A200A0,434
1260 DATA 03205CE4A907A221A03F205CE4A9
208D0102A91F8D0002A9C08D0ED4A9018D1BD0
AD8402D0034CC024AD8502D0,35
1270 DATA F3A90F8D1C02AD1C02D0FB85CBA9
0885C9A9018D1C02E6C8A5C82901AA85C8B5B6
D0034C0127A5CBC910D017EE,567
1280 DATA E806ADE806291F8DE806D00AADC3
02C994F003CEC302BDE006F04EFEE606BDE606
29039DE606D021BCAA2ABDEC,405
1290 DATA 06C980F00CDEEC06BDEC069905D2
4C3525A9009904D29905D29DEC06BDC002C99F
F00CFEC002FEC002FEC0024C,139
1300 DATA 0127BDE6062901F0034C01274C27
28BDEE06F0034C1426AD0BD0F01EA00084C18C
07D08C1ED0C904F010AACA86,817
1310 DATA C2A006206626A6C220EF27A6C8BD
0CD0F029C904D0034C0F28C908D01BADC302C9
94F0034C0F28BCA02AB9B600,916
1320 DATA 8D1ED0D0034CEF284C01274C8728
BD00D0F00920912720772820D828BD08D0F040
C904D00620D8284C0126C908,309
1330 DATA D01520D828A91085CBA9008D2410
8D02D28D03D24C0126B4C6AACABDE006F0034C
01272066268A4AAA20EF27A6,89
1340 DATA C820912720D828BD04D0F0398D1E
D0207728ADDE06D00320EF27FEEE06BDEE06C9
04D005A9009DEE06B5C4A8B9,632
1350 DATA F629C906D00B18B5B0C975A904B0
02A905A82066264C0127BD8402D009854DB5BF
D0034CB127BD7802C90FD006,391
1360 DATA 20C8264C012738E905A895C42066
264C0127B5B61879E229C9C1F009C92FF0059D
00D095B6B5B485BBB5B01879,662
1370 DATA EC29C9C5F041C922F03D85BA95B0
A007B9862991BA8810F8FEE406BDE40629079D
E406A8B9A22AA00491BABDE9,904
1380 DATA 06F00160BDE4062901A8BDAA2AAA
B9AC2A9D04D2A9A59D05D260B5B085BAB5B485
BBFEE406BDE406290F9DE406,738
1390 DATA 4AA8B9A22AA00491BABDE906F001
60BDE40629034AA8BDAA2AAAB9AE2A9D04D2A9
A59D05D260A5BFF005A20020,278
1400 DATA C228A5C0F005A20120C228A5C1F0
07C6C1A5C18D07D0AD1E02D0068D00D28D01D2
AD1FD0C907F0034CEF28ADE9,999
1410 DATA 06F005A200207727ADEA06F005A2
01207727A5BEF024EEF106ADF10629038DF106
D017A5BE85C2A9008D06D085,151
1420 DATA BEA004B1C259B22A91C28810F6AD
1C02D0FB4CD024FEE906FEE906BDE906C930F0
07BCAA2A9904D260A9009DE9,236
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38E90285BE85C2A004B1C219B22A91C28810F6
6018A5B6C5B7BD432A9003BD,65
1440 DATA 452A95C6BCAA2AA9089904D29DE9
06A98B9905D2B4C6B5B61879002A95BFB5B018
690595BC85C2A000B1C21DB0,698
1450 DATA 2A91C24C4D26207728BC9E2AB964
06186901C91AF00499640660A910996406A911
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1480 DATA 034CEF284C0127A9C88D00D2A98E
8D01D2A9058D1E0260207728A200A000A99E8D
C0028DC102A5B185BAA5B585,297
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1510 DATA D0FBA0079900D09900D28810F7A9
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1520 DATA 00000000187E3E7C6400183E7C3C
187E3C7800607C383C7E06001C3C1E3C7E7E38
00000010381C000000000018,510
1530 DATA 20000000000000387E1830000000
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1630 DATA 70707047382B0770465D2B707047
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1640 DATA 746C6500696E0000000000000000
00000074686500620072696E67000000000022
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1650 DATA 3300000000F2E9EEE700E4E5EEF3
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1660 DATA 00000000000000ADA5A4A9B5AD00
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Checksum Data

10 DATA 322,351,496,811,423,729,200,60
3,555,573,694,613,29,205,214,6818
160 DATA 771,198,962,631,491,30,155,11
4,169,239,827,872,735,180,898,7272
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1360 DATA 817,35,214,132,72,749,201,13
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1510 DATA 712,401,988,662,725,20,805,3
57,915,518,152,108,416,156,702,7637
1660 DATA 106,875,751,51,10,220,961,21
3,609,249,814,4859

Listing 2 appears on a separate page.