Star Trader

On this page

A game
Markets
Haggling
Cargo and banks
Growth
Related
Mechanics
References
Sources

Star Trader is a text trading game in BASIC whose players captain merchant ships between star systems, buying and selling goods¹. Two to twelve can play². People’s Computer Company (PCC) described it in its newsletter in January 1974 and sold it on two paper tapes for the HP 2000F³. The newsletter names no author; Dave Kaufman was the contact for more information³.

The program survives as a printed listing. PCC Games (1974) prints its two modules⁴, and What to Do After You Hit Return (1975) reprints a revised version with a guide to the bargaining and the economy⁵. Every rule below is read in the 1974 listing, through the OCR text of the Internet Archive’s scan, with the lines the OCR garbles read on the page images.

#A game

Players new to the game get the default: two to four players, two ships each, three star systems per player plus one, and 5 years^6,6. Experienced players can set each of those, the cargo limit, the spacing of the stars, the number of bids, and the profit margin². The set-up module holds the defaults in code⁷. Every ship starts at Sol with 5,000 in cash and 15 units of heavy equipment, 10 of medicine, and 10 of software⁸.

The calendar starts on January 1, 2070, and its year has 360 days⁹ in twelve 30-day months⁹. A voyage takes the straight-line distance divided by the ship’s speed, 2/7 of a light-year a day¹⁰, rounded down to whole days¹⁰. The map is 100 light-years square¹⁰.

The game has no rounds. The program always moves the ship with the earliest arrival date, breaking a tie with a coin flip, and the calendar jumps to that date¹¹. A landing is a turn: the captain trades, visits the bank if the system has one, and names the next port of call¹¹.

Voyages run late. Before departure, with probability 0.05 by default, a voyage is held 1 to 3 weeks for an inspection, the crew’s vacation, or a local holiday¹². After printing the arrival date, the program adds 1 to 3 more weeks to all but one voyage in twenty, and the ship reports the delay on landing as a computer mistake, getting lost, or pirates¹².

When the next arrival falls in a new year, the program prints a yearly report: every system’s prices, and each player’s cash aboard, bank balance, and cargo valued at the fixed prices, with a total¹³. The game ends when the next arrival falls in its last year, after that year’s January 1 report and before the landing¹⁴. Typing SAVE as a port of call punches the game onto paper tape to finish later¹⁴. The listing names no winner¹³.

#Markets

Each of the six goods has a fixed price $Q$ , from 3,000 to 5,000^15,15. Each system makes or consumes each good at a monthly rate $G$ , set by its development level $L$ and two DATA tables, $M$ and $C$ , for its development bracket¹⁶:

G = (1 + \frac{L}{15}) (M L + C)

A positive rate means the system produces the good, a negative one that it consumes it¹⁶. Young systems produce uranium, metals, and gems and need the other three goods; developed systems are the reverse¹⁶. A frontier system makes 1 uranium a month and consumes 1 software, and Sol makes 2 software and consumes 2 uranium¹⁷.

A system’s stock $S$ of a good grows by $G$ each month. The program brings it up to date whenever a ship lands, capped at 12 months¹⁸ of the rate¹⁸. A positive stock is for sale, and a negative one is a need the merchants buy against¹⁸.

The fair price $P$ follows the stock, scaled by the profit-margin constant $X_{9}$ and rounded to the nearest 100¹⁹:

P = Q (1 - sgn (S) | \frac{S}{G X_{9}} |)

A surplus lowers the price, and a need raises it¹⁹. The profit-margin setting $n$ , from 1 to 5, makes $X_{9} = 18 n$ ²⁰. Since the stock never exceeds 12 months of the rate, a fair price stays within $Q (1 \pm 12 / X_{9})$ , which is ±⅓ of the fixed price²¹ at the default setting of 2²¹.

The update gives the stock the sign of the rate. Selling a needy system more than it needs therefore leaves a surplus that the next update books as a need of the same size, less the consumption since²².

#Haggling

Merchants buy against their system’s needs and sell from its stock¹⁸. Offered more than they need, they bid on at most twice their need²³. They open at 90% (buying) and 110% (selling)²⁴ of the lot’s fair value, and they haggle for at most 3 rounds²⁵; when more than one round is allowed, they announce the last as their final offer²⁵.

When the merchants buy $X$ units, each round runs^26,24

for round k = 1 to K9:
    offer 0.9 × P × X, rounded to 100
    read the player's bid Y
    if Y ≤ P × X:           "WE'LL BUY!" at Y; stop
    if Y > (1 + z) × P × X: "WE'LL PASS THIS ONE"; stop
    P = 0.8 × P + 0.2 × Y / X
"WE'LL PASS THIS ONE"

When they sell, the test mirrors it: an offer at or above $P X$ buys, and one below $(1 - z) P X$ gets “THAT’S TOO LOW”²⁶. A deal closes at the player’s figure, and the price change lasts only for the visit²⁶.

The price window $z$ narrows each round $k$ and is widest for a lot that meets the merchants’ whole need or supply $| S |$ ²⁷:

z = {\begin{matrix} 0.5 / k & X \geq | S | \\ X / (2 | S | k) & X < | S | \end{matrix}

The 1975 guide says the same: the window “gets narrower each round of bidding”²⁷. A player who agrees a price above the cash aboard can draw the difference from the bank in a system that has one; elsewhere the offer fails as too low²⁸.

#Cargo and banks

A ship carries at most 30 tons²⁹, and gems and software don’t count toward the limit²⁹.

Only Class I and II systems have banks, and each player’s one account serves all their ships³⁰. Interest is 5% a year³¹. With $t$ the time in years since the account’s last update, the bank sets $B \leftarrow B (1 + 0.05 t)$ , without rounding³¹. It updates an account at each bank visit and every account in each yearly report, so interest compounds at least once a year³¹.

#Growth

After a ship’s visit, the program raises the system’s development level by 1.25 if no need there exceeds a month’s consumption and at most one good is still needed³². It announces a new class at each multiple of 5³². Once the average level reaches 10, a new Class IV system appears, up to 15 in all³². The newsletter says that systems on brisker trading routes grow faster³².

Mechanics

Mechanic	Kind	How
Commodity trading		six goods priced by each system's stock or need, and haggling over every lot
Price fluctuation		a price follows the system's stock, which grows each month and moves with every trade
Inventory capacity	Mass	30 tons a ship by default; gems and software weigh nothing
Compound interest		5% a year, simple between updates and added to the balance at each bank visit and each yearly report
Calendar	Months	twelve 30-day months from January 1, 2070; a voyage takes whole days
Day limit		a set number of years, 5 by default, ending on January 1 of the last
Random events		voyage delays of up to 3 weeks, some announced at departure and some only on landing

Every claim about this game, by concept (31)

general	In January 1974 the People's Computer Company newsletter described Star Trader over two pages, sent readers to Dave Kaufman for more information, and sold the program on two paper tapes with instructions for $10, written for the HP 2000F.	Publisher
	PCC Games (1974) prints Star Trader's BASIC listing in two modules, a main module of 6,819 words and a set-up module of 3,290 words, each headed with a pointer back to the January 1974 newsletter.	Publisher
	What to Do After You Hit Return (1975) reprints the two modules on pp. 143–149 in a revised version, with two pages of ideas and an explanation of the bargaining and the economic model.	Publisher
	Star Trader moves its ships one at a time in order of arrival, always taking the ship whose arrival date is earliest and breaking a tie with a coin flip, so the date jumps to that arrival.	Publisher
Calendar	Star Trader's calendar has twelve 30-day months in a 360-day year and starts on January 1, 2070.	Publisher
Calendar	A Star Trader voyage takes the straight-line distance divided by the ship's speed, `R9` light-years a day (2/7 by default, 2 a week), rounded down to whole days, on a map 100 light-years square.	Publisher
Commodity trading	Star Trader's set-up module sets its defaults in code: ships travel 2/7 of a light-year a day, stars stand at least 15 light-years apart, the delay constant `Q`, which a comment calls the probability of a delay, is 0.1, merchants make up to 3 bids, a ship carries 30 tons, the profit-margin constant `X9` is 36, and development grows in steps of 1.25.	Publisher
	Star Trader's profit-margin setting $n$ , asked for as 1 to 5 and usually 2, sets `X9` to $18 n$ , so the default `X9` is 36; the prompt says a higher number gives a lower profit.	Publisher
	Star Trader has six goods, each with a fixed price: uranium 5,000, metals 3,500, heavy equipment 4,000, medicine 4,500, computer software 3,000, and star gems 3,000.	Publisher
	Each Star Trader system makes or needs each good at a monthly rate $G = (1 + L / 15) (M L + C)$ , where $L$ is the system's development level and $M$ and $C$ come from DATA statements for its development bracket; a positive rate means it produces the good, a negative one that it consumes it.	Publisher
	Computed from Star Trader's DATA tables: a frontier system, at development level 0, makes 1 uranium, 0.75 metals, and 0.5 gems a month and consumes 0.75 heavy equipment, 0.5 medicine, and 1 software; Sol, at level 15, makes 1.5 heavy equipment, 1 medicine, and 2 software and consumes 2 uranium, 1.5 metals, and 1 gems.	Publisher
	Star Trader sets a system's fair price for a good from its fixed price $Q$ , its stock $S$ , its rate $G$ , and the profit-margin constant $X_{9}$ : $P = Q (1 - sgn (S) \| S / (G X_{9}) \|)$ , rounded to the nearest 100, so a surplus lowers the price and a need raises it.	Publisher
	Computed from lines 3940–3950: since the stock never exceeds 12 months of the rate, a fair price stays within $Q (1 \pm 12 / X_{9})$ , which is ±⅓ of the fixed price at the default margin of 2, ±⅔ at 1, and ±2/15 at 5.	Publisher
	When a Star Trader player offers merchants more of a good than they need, they bid on at most twice their need.	Publisher
	Star Trader's merchants open each round at 90% of the fair value of the units when buying from the player and 110% when selling to the player, rounded to the nearest 100.	Publisher
	Star Trader's merchants haggle over each good for at most `K9` rounds, 3 by default; when `K9` is 2 or more, they announce the last round as their final offer.	Publisher
	When Star Trader's merchants buy $X$ units at fair price $P$ , a player's bid $Y$ at or under $P X$ sells, one over $(1 + z) P X$ ends the deal, and one between moves the price to $0.8 P + 0.2 Y / X$ for another round; when they sell, an offer at or over $P X$ buys, one under $(1 - z) P X$ ends the deal, and one between moves the price the same way.	Publisher
	Star Trader's price window $z$ is $0.5 / k$ in round $k$ when the player trades at least the merchants' whole need or supply $\| S \|$ , and $X / (2 \| S \| k)$ for a smaller lot of $X$ units, so it narrows each round and is widest for a full lot.	Publisher
	In a Star Trader system with a bank, a player whose accepted offer exceeds the cash aboard may draw on the bank to pay; elsewhere, or if the bank can't cover it, the offer fails as too low.	Publisher
	Each year Star Trader prints every system's prices and each player's cash aboard ships, bank balance, and cargo valued at the fixed prices, with their total.	Publisher
	After a ship's visit, Star Trader raises the system's development level by `G9` (1.25 by default) if no need left there exceeds one month's consumption and at most one good is still needed; it announces a new class at each multiple of 5, and once the average level reaches 10, a new Class IV system appears, up to 15 systems.	Publisher
Compound interest	Star Trader's banks are only in Class I and II systems, and each player has one account that every one of their ships can use.	Publisher
Compound interest	Star Trader's bank multiplies a balance by $1 + 0.05 t$ , where $t$ is the time in years since the account's last update, with no rounding; it updates a player's account on each bank visit and every account in each yearly report, so interest compounds at least once a year.	Publisher
Day limit	When any player hasn't played before, Star Trader skips the setup questions and starts a game for 2 to 4 players with two ships each, three stars per player plus one, lasting 5 years.	Publisher
	A custom game of Star Trader takes 2 to 12 players with at most 12 ships in all, 4 to 13 stars, any whole number of years, a cargo limit of at least 25 tons, a minimum star spacing of 10 to 25 light-years, at least one bid, and a profit-margin setting that the prompt asks to be 1 to 5 and the code caps at 5, with no lower bound.	Publisher
	A Star Trader game lasts a set number of years and ends when the next arrival falls in its last year, `Y9`, after the January 1 report for that year and before the landing.	Publisher
Inventory capacity	Every Star Trader ship starts at Sol with 5,000 in cash and 15 units of heavy equipment, 10 of medicine, and 10 of software, a net weight of 25 tons because software is weightless.	Publisher
Inventory capacity	A Star Trader ship carries at most `W` tons, 30 by default, and gems and software don't count toward it.	Publisher
Price fluctuation	On each visit Star Trader adds the months since the system's last update times its rate $G$ to the system's stock of each good, then caps the stock at 12 months of the rate and gives it the sign of $G$ .	Publisher
Price fluctuation	Computed from line 3940: because the update gives the stock the sign of the rate, a surplus the player sold into a system that needs a good is booked at the next update as a need of the same size, less the consumption since.	Publisher
Random events	Star Trader can delay a voyage twice: before departure, with probability $Q / 2$ (0.05 by default), it announces a delay of 1 to 3 weeks for an inspection, a crew's vacation, or a local holiday; after printing the arrival date, with probability $1 - Q / 2$ (0.95 by default), it adds a further 1 to 3 weeks that the ship reports on landing as a computer mistake, getting lost, or pirates.	Publisher

References

^Star Trader, which People's Computer Company printed in January 1974, has each player captain trading ships between star systems, buying and selling merchandise.PublisherPeople's Computer Company, Jan. 1974
How we know
YOU WILL TRAVEL FROM STAR SYSTEM TO STAR SYSTEM, BUYING AND SELLING MERCHANDISE.
p. 4 · archived copy ↗
The quote matches our archived copy.
Checked by a second AI model, 2026-10-21.
In the claim ledger
^ a bA custom game of Star Trader takes 2 to 12 players with at most 12 ships in all, 4 to 13 stars, any whole number of years, a cargo limit of at least 25 tons, a minimum star spacing of 10 to 25 light-years, at least one bid, and a profit-margin setting that the prompt asks to be 1 to 5 and the code caps at 5, with no lower bound.PublisherPCC Games, 1974 · What to Do After You Hit Returnrevised
How we know
970 PRINT "2,3,4, ... ,12 CAN PLAY"
p. 29, set-up module lines 960–970 · archived copy ↗
1030 IF T9 <= 12 THEN 1070 1040 PRINT "I CAN'T KEEP TRACK OF MORE THAN 12 SHIPS;" … 1100 PRINT "FROM 4 TO 13 STARS" … 1120 PRINT "ENTER THE LENGTH OF GAME IN YEARS"; … 1140 IF X >= 1 AND INT(X)=X THEN 1170 … 1200 IF W<25 THEN 1180 … 1240 PRINT "MIN SPACING 10, MAX 25" … 1280 IF K9<1 THEN 1260
p. 30, set-up module lines 1030–1330 · archived copy ↗
Pick any length game (a million years?)
p. 96 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^ a bIn January 1974 the People's Computer Company newsletter described Star Trader over two pages, sent readers to Dave Kaufman for more information, and sold the program on two paper tapes with instructions for $10, written for the HP 2000F.PublisherPeople's Computer Company, Jan. 1974
How we know
A copy of the two tapes with instructions costs $10. It's written for the HP 2000F, with PRINT USING, HP strings, but no files or ENTER statements. … For more info, write to … Dave Kaufman
p. 4 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^PCC Games (1974) prints Star Trader's BASIC listing in two modules, a main module of 6,819 words and a set-up module of 3,290 words, each headed with a pointer back to the January 1974 newsletter.PublisherPCC Games, 1974
How we know
See Jan. '74 issue PCC Vol. 2, No. 3, pages 4,5. … Length: 6819 words.
p. 25 · archived copy ↗
Length: 3290 words.
p. 29 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^What to Do After You Hit Return (1975) reprints the two modules on pp. 143–149 in a revised version, with two pages of ideas and an explanation of the bargaining and the economic model.PublisherWhat to Do After You Hit Returnrevised
How we know
(set-up module)
p. 143 · archived copy ↗
(main module)
p. 145 · archived copy ↗
HOW LOCAL MERCHANTS BARGAIN
p. 97 · archived copy ↗
IS ENROUTE TO
p. 145, lines 406–428 · archived copy ↗
IF GO#5 AND GO#10 AND GO#15 THEN 2220
p. 147, line 2162 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^ a bWhen any player hasn't played before, Star Trader skips the setup questions and starts a game for 2 to 4 players with two ships each, three stars per player plus one, lasting 5 years.PublisherPCC Games, 1974
How we know
590 PRINT "HAVE ALL PLAYERS PLAYED BEFORE"; … 690 PRINT "2,3, OR 4 CAN PLAY" 700 GOTO 660 710 T9=2*P9 720 S9=3*P9+1 730 Y9=Y1+5
p. 29, set-up module lines 590–740 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^Star Trader's set-up module sets its defaults in code: ships travel 2/7 of a light-year a day, stars stand at least 15 light-years apart, the delay constant Q, which a comment calls the probability of a delay, is 0.1, merchants make up to 3 bids, a ship carries 30 tons, the profit-margin constant X9 is 36, and development grows in steps of 1.25.PublisherPCC Games, 1974revised
How we know
200 LET R9=2/7 210 LET D9=15 220 LET Q=.1 230 LET K9=3 240 LET W=30 250 LET X9=36 260 LET G9=1.25
p. 29, set-up module lines 130–260 · archived copy ↗
130 REM R9 IS THE SPEED OF A SHIP IN LIGHT-YEARS PER DAY … 150 REM Q IS THE PROBABILITY OF A DELAY 160 REM K9 IS THE MAX NUMBER OF BIDDING ROUNDS 170 REM W IS THE MAX WEIGHT OF A TRADING SHIP 180 REM X9 CONTROLS THE PROFIT MARGIN; HIGH X9 LIMITS THE % 190 REM G9 IS THE STELLAR DEVELOPMENT INCREMENT 1<=G9<=5
p. 29, set-up module lines 130–190 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^Every Star Trader ship starts at Sol with 5,000 in cash and 15 units of heavy equipment, 10 of medicine, and 10 of software, a net weight of 25 tons because software is weightless.PublisherPCC Games, 1974 · People's Computer Company, Jan. 1974revised
How we know
450 PRINT "ALL SHIPS START AT SOL"
p. 25, line 450 · archived copy ↗
1700 T[1,T1]=T[2,T1]=T[6,T1]=0 1710 T[3,T1]=15 1720 T[4,T1]=T[5,T1]=10 1730 T[7,T1]=25 … 1760 T[11,T1]=5000
p. 30, set-up module lines 1700–1760 (block · archived copy ↗
$ ON BOARD UR MET HE MED SOFT GEMS NET WT
p. 5 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^ a bStar Trader's calendar has twelve 30-day months in a 360-day year and starts on January 1, 2070.PublisherPCC Games, 1974
How we know
270 REM D1 IS THE DAY OF THIS YEAR (1<=D1<=360) 280 REM Y1 IS THIS YEAR 290 LET D1=1 300 LET Y1=2070
p. 29, set-up module lines 270–300 · archived copy ↗
3040 IF T[9,T1] <= 360 THEN 3070 3050 T[9,T1]=T[9,T1]-360 3060 T[10,T1]=T[10,T1]+1 3070 M=INT((T[9,T1]-1)/30)
p. 27, lines 3040–3070 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a b cA Star Trader voyage takes the straight-line distance divided by the ship's speed, R9 light-years a day (2/7 by default, 2 a week), rounded down to whole days, on a map 100 light-years square.PublisherPCC Games, 1974 · People's Computer Company, Jan. 1974
How we know
2910 D2=SQR((S[11,S1]-S[11,I])^2+(S[12,S1]-S[12,I])^2)/R9 2920 D2=INT(D2)
p. 27, lines 2910–2920 · archived copy ↗
THE MAP IS 100 LIGHT-YEARS BY 100 LIGHT-YEARS.
p. 29, line 5470 · archived copy ↗
YOUR SHIPS CAN TRAVEL ABOUT TWO LIGHTYEARS IN A WEEK AND CAN CARRY UP TO 30 TONS OF CARGO.
p. 4 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a bStar Trader moves its ships one at a time in order of arrival, always taking the ship whose arrival date is earliest and breaking a tie with a coin flip, so the date jumps to that arrival.PublisherPCC Games, 1974
How we know
690 FOR I=2 TO T9 700 IF T[10,I]<Y THEN 740 710 IF T[10,I]>Y THEN 770 720 IF T[9,I]>D THEN 770 730 IF T[9,I]=D AND RND(0)>.5 THEN 770
p. 25, lines 660–770 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a bStar Trader can delay a voyage twice: before departure, with probability $Q / 2$ (0.05 by default), it announces a delay of 1 to 3 weeks for an inspection, a crew's vacation, or a local holiday; after printing the arrival date, with probability $1 - Q / 2$ (0.95 by default), it adds a further 1 to 3 weeks that the ship reports on landing as a computer mistake, getting lost, or pirates.PublisherPCC Games, 1974revised
How we know
2960 PRINT "SHIP DOES NOT PASS INSPECTION"; … 2980 PRINT "CREWMEN DEMAND A VACATION"; … 3000 PRINT "LOCAL HOLIDAY SOON" 3010 PRINT " - ";I;" WEEK DELAY."
p. 27, lines 2930–3020 · archived copy ↗
3100 REM UPDATE ETA PLUS RANOM DELAY FACTOR (0,1,2 OR 3 WEEKS) 3110 I=(INT(RND(0)*3)+1)*(RND(0)>Q/2)
p. 27, line 3100 · archived copy ↗
2930 IF RND(0)>Q/2 THEN 3030
p. 27, line 2930 · archived copy ↗
1020 PRINT "3 WEEKS LATE - PIRATES ATTACKED MIDVOYAGE" … 1040 PRINT "2 WEEKS LATE - 'WE GOT LOST.SORRY'" … 1060 PRINT "1 WEEK LATE - 'OUR COMPUTER MADE A MISTAKE'"
p. 25, lines 1020–1060 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^ a bEach year Star Trader prints every system's prices and each player's cash aboard ships, bank balance, and cargo valued at the fixed prices, with their total.PublisherPCC Games, 1974
How we know
3680 PRINT "NUMBER $ ON SHIPS $ IN BANK CARGOES TOTALS" … 3780 M2=M2+T[K,P9*U+P1]*Q[K] … 3810 M3=M2+M1+B[1,P1]
p. 27, lines 3680–3820 · archived copy ↗
3620 PRINT "('+' MEANS SELLING AND '-' MEANS BUYING)"
p. 27, line 3620 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a bA Star Trader game lasts a set number of years and ends when the next arrival falls in its last year, Y9, after the January 1 report for that year and before the landing.PublisherPCC Games, 1974revised
How we know
826 PRINT "THE LAST YEAR OF THIS GAME IS ";Y9;" BUT IF YOU" 828 PRINT "WANT TO QUIT BEFORE THEN, YOU CAN TYPE 'SAVE' AS" 829 PRINT "YOUR NEXT PORT OF CALL - THIS WILL PUNCH A TAPE" … 840 IF Y1<Y9 THEN 900
p. 25, lines 780–870 · archived copy ↗
730 Y9=Y1+5
p. 29, set-up module line 730 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^ a bStar Trader has six goods, each with a fixed price: uranium 5,000, metals 3,500, heavy equipment 4,000, medicine 4,500, computer software 3,000, and star gems 3,000.PublisherPCC Games, 1974 · People's Computer Company, Jan. 1974
How we know
200 REM P CONTAINS THE FAIR PRICES ON THE LOCAL PLANET 210 REM Q HAS THE FIXED PRICES … 270 DATA 5000,3500,4000,4500,3000,3000
p. 25, lines 200–280 · archived copy ↗
N$="UR … MET … HE … MED … SOFT GEMS"
p. 25, line 280 · archived copy ↗
UR URANIUM … MET METALS … HE HEAVY EQUIPMENT … MED MEDICINE … SOFT COMPUTER SOFTWARE … GEMS STAR GEMS
p. 5 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a b cEach Star Trader system makes or needs each good at a monthly rate $G = (1 + L / 15) (M L + C)$ , where $L$ is the system's development level and $M$ and $C$ come from DATA statements for its development bracket; a positive rate means it produces the good, a negative one that it consumes it.PublisherPCC Games, 1974 · What to Do After You Hit Returnrevised
How we know
90 REM M AND C DETERMINE A STAR'S PRODUCTIVITY/MONTH 92 REM PROD/MO. = S(7,J) * M(I,R1) + C(I,R1) 94 REM WHERE J IS THE STAR ID #,I THE MERCHANDISE #, 96 REM AND R1 IS THE DEVELOPMENT CLASS OF THE STAR
p. 29, set-up module lines 90–96 · archived copy ↗
3870 R1=1+(S[7,S1] >= 5)+(S[7,S1] >= 10) … 3900 G[I]=(1+S[7,S1]/15)*(M[I,R1]*S[7,S1]+C[I,R1])
p. 27, lines 3870–3900 · archived copy ↗
Star Systems have surpluses of Uranium, Raw Metals and Gems but need alot of Heavy Equipment, Medicine and Computer
p. 97 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^Computed from Star Trader's DATA tables: a frontier system, at development level 0, makes 1 uranium, 0.75 metals, and 0.5 gems a month and consumes 0.75 heavy equipment, 0.5 medicine, and 1 software; Sol, at level 15, makes 1.5 heavy equipment, 1 medicine, and 2 software and consumes 2 uranium, 1.5 metals, and 1 gems.PublisherPCC Games, 1974revised
How we know
2410 REM MODEL #1 2420 DATA -.1,-.2,-.1,0,-.1,-.1,0,.1,.1,-.1,.1,0,.1,.2,.1,.1,-.1,0 2430 DATA 1,1.5,.5,.75,.75,.75,-.75,-.75,-.75,-.5,-1.5,.5,-1,-1.5 2440 DATA -.5,.5,1.5,-.5
p. 31, set-up module lines 2410–2440 · archived copy ↗
304 RESTORE 2410 306 MAT READ M,C
p. 29, set-up module lines 304–306 · archived copy ↗
3870 R1=1+(S[7,S1] >= 5)+(S[7,S1] >= 10) … 3900 G[I]=(1+S[7,S1]/15)*(M[I,R1]*S[7,S1]+C[I,R1])
p. 27, lines 3870–3900 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^ a b c dOn each visit Star Trader adds the months since the system's last update times its rate $G$ to the system's stock of each good, then caps the stock at 12 months of the rate and gives it the sign of $G$ .PublisherPCC Games, 1974 · What to Do After You Hit Return
How we know
3880 D2=12*(Y1-S[10,S1])+(D1-S[9,S1])/30 … 3940 S[I,S1]=SGN(G[I])*(ABS(G[I]*12) MIN ABS(S[I,S1]+D2*G[I]))
p. 27, lines 3880 and 3940 · archived copy ↗
MIN ABS(S(I,S1)+D2*G(I)))
p. 148, line 3940 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a bStar Trader sets a system's fair price for a good from its fixed price $Q$ , its stock $S$ , its rate $G$ , and the profit-margin constant $X_{9}$ : $P = Q (1 - sgn (S) | S / (G X_{9}) |)$ , rounded to the nearest 100, so a surplus lowers the price and a need raises it.PublisherPCC Games, 1974
How we know
3910 IF ABS(G[I])>.01 THEN 3940 3920 P[I]=0 … 3950 P[I]=Q[I]*(1-SGN(S[I,S1])*ABS(S[I,S1]/(G[I]*X9))) 3960 P[I]=100*INT(P[I]/100+.5)
p. 27, lines 3910–3960 · archived copy ↗
380 REM X9 CONTROLS THE PROFIT MARGIN; HIGH X9 LIMITS THE %
p. 25, line 380 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^Star Trader's profit-margin setting $n$ , asked for as 1 to 5 and usually 2, sets X9 to $18 n$ , so the default X9 is 36; the prompt says a higher number gives a lower profit.PublisherPCC Games, 1974revised
How we know
1290 PRINT "SET THE PROFIT MARGIN(1,2,3,4 OR 5)...THE HIGHER" 1300 PRINT "THE NUMBER, THE LOWER THE PROFIT % ... USUALLY SET TO 2" … 1330 X9=18*(ABS(X9) MIN 5)
p. 30, set-up module lines 1290–1330 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^ a bComputed from lines 3940–3950: since the stock never exceeds 12 months of the rate, a fair price stays within $Q (1 \pm 12 / X_{9})$ , which is ±⅓ of the fixed price at the default margin of 2, ±⅔ at 1, and ±2/15 at 5.PublisherPCC Games, 1974
How we know
3940 S[I,S1]=SGN(G[I])*(ABS(G[I]*12) MIN ABS(S[I,S1]+D2*G[I])) 3950 P[I]=Q[I]*(1-SGN(S[I,S1])*ABS(S[I,S1]/(G[I]*X9)))
p. 27, lines 3940–3950 · archived copy ↗
1330 X9=18*(ABS(X9) MIN 5)
p. 30, set-up module line 1330 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^Computed from line 3940: because the update gives the stock the sign of the rate, a surplus the player sold into a system that needs a good is booked at the next update as a need of the same size, less the consumption since.PublisherPCC Games, 1974
How we know
3940 S[I,S1]=SGN(G[I])*(ABS(G[I]*12) MIN ABS(S[I,S1]+D2*G[I]))
p. 27, line 3940 · archived copy ↗
1270 IF X <= 2*-INT(S[I1,S1]) THEN 1300 1280 X=2*-INT(S[I1,S1]) 1290 PRINT TAB(5);"WE'LL BID ON ";X;" UNITS." … 1470 S[I1,S1]=S[I1,S1]+X
p. 26, lines 1270–1290 and 1470 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^When a Star Trader player offers merchants more of a good than they need, they bid on at most twice their need.PublisherPCC Games, 1974 · People's Computer Company, Jan. 1974
How we know
1270 IF X <= 2*-INT(S[I1,S1]) THEN 1300 1280 X=2*-INT(S[I1,S1]) 1290 PRINT TAB(5);"WE'LL BID ON ";X;" UNITS."
p. 26, lines 1270–1290 · archived copy ↗
MED WE NEED 4 UNITS.HOW MANY ARE YOU SELLING?13 … WE'LL BID ON 8 UNITS.
p. 5 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a bStar Trader's merchants open each round at 90% of the fair value of the units when buying from the player and 110% when selling to the player, rounded to the nearest 100.PublisherPCC Games, 1974
How we know
1350 PRINT 100*INT(.009*P[I1]*X+.5);" WHAT DO YOU BID";
p. 26, line 1350 · archived copy ↗
1750 PRINT 100*INT(.011*P[I1]*X+.5);
p. 26, line 1750 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a bStar Trader's merchants haggle over each good for at most K9 rounds, 3 by default; when K9 is 2 or more, they announce the last round as their final offer.PublisherPCC Games, 1974 · People's Computer Company, Jan. 1974revised
How we know
360 REM K9 IS THE MAX NUMBER OF BIDDING ROUNDS
p. 25, line 360 · archived copy ↗
1700 FOR K1=1 TO K9 1710 IF K1#K9 MAX 2 THEN 1740 1720 PRINT TAB(5);"OUR FINAL OFFER:";
p. 26, lines 1700–1720 · archived copy ↗
OUR FINAL OFFER
p. 5 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^ a b cWhen Star Trader's merchants buy $X$ units at fair price $P$ , a player's bid $Y$ at or under $P X$ sells, one over $(1 + z) P X$ ends the deal, and one between moves the price to $0.8 P + 0.2 Y / X$ for another round; when they sell, an offer at or over $P X$ buys, one under $(1 - z) P X$ ends the deal, and one between moves the price the same way.PublisherPCC Games, 1974 · What to Do After You Hit Return
How we know
1370 IF Y <= P[I1]*X THEN 1430 1380 IF Y>(1+FNZ(X))*P[I1]*X THEN 1410 1390 P[I1]=.8*P[I1]+.2*Y/X
p. 26, lines 1370–1390 · archived copy ↗
1780 IF Y >= P[I1]*X THEN 1840 1790 IF Y<(1-FNZ(X))*P[I1]*X THEN 1820 1800 P[I1]=.8*P[I1]+.2*Y/X
p. 26, lines 1780–1800 · archived copy ↗
But if you're within their Price Window, they will adjust and continue bargaining!
p. 97 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a bStar Trader's price window $z$ is $0.5 / k$ in round $k$ when the player trades at least the merchants' whole need or supply $| S |$ , and $X / (2 | S | k)$ for a smaller lot of $X$ units, so it narrows each round and is widest for a full lot.PublisherPCC Games, 1974 · What to Do After You Hit Return
How we know
290 REM FNZ COMPUTES THE PRICE WINDOW THROUGH WHICH A BID IS 300 REM ACCEPTABLE FOR FURTHER HAGGLING 310 DEF FNZ(X)=(FNY(X)*.5+(NOT FNY(X))*X/(2*ABS(S[I1,S1])))/K1 320 DEF FNY(X)=X >= ABS(S[I1,S1])
p. 25, lines 290–320 · archived copy ↗
Beware - the Price Window gets narrower each round of bidding. … The Price Window is widest when the number of units you're bargaining for satisfies the local merchants.
p. 97 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^In a Star Trader system with a bank, a player whose accepted offer exceeds the cash aboard may draw on the bank to pay; elsewhere, or if the bank can't cover it, the offer fails as too low.PublisherPCC Games, 1974
How we know
1840 IF Y <= T[11,T1] THEN 1910 1850 PRINT TAB(5);"YOU BID $";Y;" BUT YOU HAVE ONLY $";T[11,T1] 1860 GOSUB 4310 1870 IF S[7,S1]<10 OR T[11,T1]+B[1,B1]<Y THEN 1820
p. 26, lines 1840–1900 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a bA Star Trader ship carries at most W tons, 30 by default, and gems and software don't count toward it.PublisherPCC Games, 1974
How we know
1600 IF I1>4 OR X+T[7,T1] <= W THEN 1660
p. 26, line 1600 · archived copy ↗
3400 PRINT TAB(5);"EACH TRADING SHIP CAN CARRY MAX ";W;" TONS CARGO." 3410 PRINT "STAR GEMS AND COMPUTER SOFTWARE, WHICH AREN'T SOLD BY THE" 3420 PRINT "TON, DON'T COUNT."
p. 27, lines 3400–3420 · archived copy ↗
240 LET W=30
p. 29, set-up module line 240 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^Star Trader's banks are only in Class I and II systems, and each player has one account that every one of their ships can use.PublisherPCC Games, 1974 · People's Computer Company, Jan. 1974
How we know
2000 IF S[7,S1]<10 OR T[11,T1]+B[1,B1]=0 THEN 2040
p. 26, line 2000 · archived copy ↗
ONLY CLASS I AND CLASS II STAR SYSTEMS HAVE BANKS ON THEM. THEY PAY 5% INTEREST AND ANY MONEY YOU DEPOSIT ON ONE PLANET IS AVAILABLE ON ANOTHER
p. 4 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Checked by a second AI model, 2026-10-22.
In the claim ledger
^ a b cStar Trader's bank multiplies a balance by $1 + 0.05 t$ , where $t$ is the time in years since the account's last update, with no rounding; it updates a player's account on each bank visit and every account in each yearly report, so interest compounds at least once a year.PublisherPCC Games, 1974revised
How we know
4370 REM ***<BANK UPDATE> GOSUB 4380 B[1,B1]=B[1,B1]*(1+.05*(Y1-B[3,B1]+(D1-B[2,B1])/360)) 4390 B[2,B1]=D1 4400 B[3,B1]=Y1
p. 28, lines 4370–4400 · archived copy ↗
3690 FOR B1=1 TO P9 3700 GOSUB 4380 3710 NEXT B1
p. 27, lines 3690–3710 · archived copy ↗
4070 GOSUB 4380
p. 28, line 4070 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger
^ a b c dAfter a ship's visit, Star Trader raises the system's development level by G9 (1.25 by default) if no need left there exceeds one month's consumption and at most one good is still needed; it announces a new class at each multiple of 5, and once the average level reaches 10, a new Class IV system appears, up to 15 systems.PublisherPCC Games, 1974 · People's Computer Company, Jan. 1974revised
How we know
2090 IF S[I,S1] >= 0 THEN 2120 2100 IF S[I,S1]<G[I] THEN 660 2110 J=J+1 2120 NEXT I 2130 IF J>1 THEN 660
p. 26, lines 2090–2130 · archived copy ↗
2150 S[7,S1]=S[7,S1]+G9 … 2190 PRINT "STAR SYSTEM ";S$[S[8,S1],S[8,S1]+3];" IS NOW A CLASS";
p. 26, lines 2150–2190 · archived copy ↗
2220 IF S9=15 THEN 660 … 2270 IF J/S9<10 THEN 660 … 2380 PRINT "A NEW STAR SYSTEM HAS BEEN DISCOVERED! IT IS A CLASS IV"
p. 26, lines 2220–2270 and 2380 · archived copy ↗
As the years progress, the star systems will slowly develop, and those on the brisker trading routes will grow faster.
p. 4 · archived copy ↗
Checked against the evidence by its author, an AI model, 2026-10-22.
Revised after a check by a second AI model, 2026-10-22.
In the claim ledger

Sources

Primary

Kaufman, Dave. 1974. “Star Trader.” People's Computer Company, vol. 2, no. 3, pp. 4–5. People's Computer Company. original · archived · licence, all uses
Company, People's Computer. 1974. “PCC Games.” People's Computer Company. original · archived · licence, all uses
Company, People's Computer. 1975. “What to Do After You Hit Return, or P.C.C.'s First Book of Computer Games.” People's Computer Company. original · archived · licence, all uses