VERIFIED · 02.10.2026 AI help: yes reviewer: awaiting teacher and psychologist

Games Come Home: Consoles and Home Computers

The first video games lived in arcades and in big computers. Then a box was connected to the television at home. How did a game “remember” how far you had got? Sometimes it gave you a password, sometimes it kept it in the cartridge. Today you will try both ways on your own made-up console.

⏱ 10–15 min Master The Story of Games · 5 Grades 5–6

You will be able to explain how the first home consoles and computers loaded and saved a game — chip cartridge, cassette tape, password, battery memory — and say what each way was good for.

For parents: a one-page guide — dinner questions and a paper console.

01Remember

You already know some things from earlier lessons. Think first, then open the answer.

What forgets when the power goes off — the working memory or the storage?

The working memory (RAM) forgets. The storage keeps things even without power.

How does a cassette tape carry 0s and 1s?

With sound: two different sounds. On the ZX Spectrum the short, higher one is 0 and the long, lower one is 1. That was in the lesson “The Singing Tape”.

What is a life and what is a level in a game?

A life is one more try. A level is a part of the game with new tasks. Today we see how a game remembers which level you reached and how many lives you have left.

02Story

The idea. In August 1966 the engineer Ralph Baer had an idea: to play games on the ordinary television at home. With two helpers he built seven prototypes. People called the seventh the “Brown Box”. The company Magnavox released it in the USA in September 1972 as the Magnavox Odyssey — the first commercial home console.

A box with no memory. The Odyssey was strange. It showed only three square dots and one line, in black and white and with no sound. It did not count points. That is why the box held dice, play money, cards and score sheets, and see-through plastic sheets with pictures were stuck on the screen. The “games” were circuit-board cards: when you plugged one in, it changed the wiring inside, like switches. There was no program in a chip and nothing to save.

The chip cartridge. In November 1976 the Fairchild Channel F came out — the first home console with a microprocessor and swappable ROM cartridges. The game is recorded in the ROM chip. The processor reads it like ordinary memory, so the game starts almost instantly. In 1977 the Atari VCS (later called the Atari 2600) came out with nine games on 2 KB cartridges, and cartridges became common. ROM means “read-only memory”: the game is inside and does not change.

Tiny memory. The Atari 2600 itself had only 128 bytes of working memory. One byte is one letter, so that is about two short sentences. According to Wikipedia the first consoles also had no memory that remembers without power. So there was nowhere to write down how far you had got.

Computers and tape. In 1977 three home computers also came out: the Apple II, the Commodore PET 2001 and the TRS-80. The magazine Byte later called them the “1977 Trinity”. A disk drive at first cost as much as the computer or more, while almost every home had a tape recorder. So many computers kept their programs on cassette — the one that “sings”. It was slow: usual speeds are 300–1200 baud, and even a small memory took many minutes. A tape is not read from the middle; you have to wind it. Reading errors happened often. But the computer could also write to it — your game or your program.

Saving on a console. A console had nothing to write on. So many games showed a short password of letters and digits on the screen, with your progress “hidden” in it. You write it on paper and type it next time. That is how it is in Metroid, which came out in the USA in 1987. Reviewers said different things about its password — some “tedious”, others “very handy”. Later a small memory with a battery was put into the cartridge itself, and it keeps the game even when the console is off. The NES version of The Legend of Zelda (USA, 22 August 1987) is one: “for the first time” on the NES a game could save. According to Wikipedia the earliest console game with battery saving in the cartridge is Pop and Chips (1985) for the Super Cassette Vision.

⚠️ Where sources disagree

When you read about the history of technology, not every page says the same thing. Three examples:

Are the Odyssey's cards “cartridges”? One page calls them a forerunner of cartridges. Another says they are not ROM cartridges like the later ones. The first ROM cartridges, according to Wikipedia, were the Channel F's in 1976. We say: the Odyssey's boards are not chip cartridges.
When exactly did the Atari 2600 come out? Wikipedia writes “around September 1977” — even it is not sure of the month. So we write only “in 1977”.
Is a password handy or a nuisance? Some say one, some the other. That is not a mistake: people are different.

So we ask: “Who wrote this, and how do they know?”

Want to see more? Read with an adult, in the “Retro” section, the articles (in Bulgarian) about the Apple II, the TRS-80, the Commodore PET and the ZX Spectrum.

03Worked example

How our made-up game “Circle” turns one state into a password. The game has 9 levels, up to 9 circles and up to 3 lives. Say: level 3, 5 circles, 2 lives.

State → numbers
We write level 3 as 2 (level minus 1, so that we start from 0). The circles are 5. The 2 lives we write as 1 (lives minus 1).
Numbers → bits
2 is 0010, 5 is 0101, 1 is 01. Together: 0010010101 — ten bits.
Bits → symbols
We split them into two groups of five bits: 00100 and 10101, that is 4 and 21. The game has an alphabet of 32 symbols: ABCDEFGHJKLMNPQRSTUVWXYZ23456789 (no I and O — they are easy to mix up with 1 and 0). Symbol no. 4 is E, symbol no. 21 is X.
Check symbol
We work out 4 × 5 + 21 × 3 + 11 = 94. Dividing by 32 leaves 30, and symbol no. 30 is 8. The password is EX8. This is like the check number of the cassette in its lesson: if you get ONE letter wrong, the sum will not work out.

STATE3 · 5 · 2

BITS0010010101

SYMBOLSE · X

PASSWORDEX8

There are 9 × 10 × 3 = 270 states. Two symbols of 32 give 32 × 32 = 1024 possibilities — enough. If the game remembers more things, the password gets longer.

Five ways to keep a game — see the table. The facts are from the sources above; the last row is our own logic (RAM forgets without power).

Way	Where the game is	What can go wrong
Cassette tape	recorded as sound on tape; takes many minutes to read	reading errors; the tape has to be wound
Chip cartridge (ROM)	in the chip, read-only; starts almost instantly	cannot save anything; costs more and holds less than a floppy disk
Floppy disk	on a disk the computer can read and write	at first it cost as much as the computer or more
Password	on paper, in your hands	a wrong letter; a lost sheet
Battery memory	a small chip in the cartridge, powered by a battery	when the battery runs out, the memory forgets

04Try it

1 · Predict

A console has no disk. You play up to level 5 and the power goes off. How can the game “remember” level 5 for tomorrow? Choose before you check.

2 · Run: the console “Circle”

This is our own made-up console and game. It does not look like a real game and has no sound. Nothing is saved anywhere: if you close the page, everything disappears. You choose what kind of cartridge it is, and the buttons play for you: take a circle, go up a level, or lose a life.

What kind of cartridge? No saving With a password With memory and a battery

3 · Change

Choose “No saving”. Switch on, get to level 3 and switch off. Switch on again. What is left?
Choose “With a password”. Get to level 3 and press “Save” — you get a password. Write it on paper. Switch off, switch on and type it in the box. Does the game carry on from there?
Press “Change one letter” and then “Load”. What does the game say? Why is it good for a password to have a check symbol?
Choose “With memory and a battery”, get to level 4 and press “Save”. Switch off and on. Then tick “The battery in the cartridge is flat”, switch off and on again. What happened to the game?
Think: which cartridge is easiest to lose — a sheet with a password or a battery? And if the game has 99 levels and 20 items, how will the password change?

05No screen: a console on paper

You need one more person (mum, dad, a brother or a friend), paper, a pencil, a die and three buttons or coins. You are the player, your helper is the power.

Draw a track of 9 squares — these are the levels. Put a button on square 1 and two more buttons at the side — those are your lives. You will draw circles on the paper.
Roll the die. On 2, 3, 4 or 5 you move the button to the next square. On 6 you draw a circle. On 1 you take away a life. Play six turns.
Cartridge “No saving”. Your helper says “The power went off!” and hides the paper. What do you remember? You start again.
Cartridge “Password”. Before the power goes off, write the password: level, circles, lives and, at the end, their sum, for example 3-2-2-7. After “The power went off!” your helper checks the sum. If it does not work out, the password is wrong. That catches a mistake, but not every mistake. Cleverer check numbers catch more.
Cartridge “Battery memory”. Put a small note with the level, the circles and the lives into an envelope — that is the cartridge's memory. The power goes off, the paper is hidden, but the envelope stays. Then your helper says “The battery is flat!” and hides the note. What happened?

✋

Look only

If there is an old console, cartridge or toy with a battery at home, look at it only from outside and with an adult. Do not open it, do not take out batteries and do not plug anything in. Nothing is plugged in during this lesson.

06Make your own: saving for my game

Invent a game on paper and your own way to save it.

Decide what the game must remember — for example a level, lives and two items.
Work out how many different states there are (like 9 × 10 × 3 in our game).
Invent a code of at most five symbols and add a check symbol at the end by your own rule.
Give the code to another person and ask them to “load” the game from it.
Bonus: get one letter wrong on purpose. Does your check symbol catch it?

07What I learned

The first home consoles often had no memory that remembers without power. So the game gave you a password, and later got battery memory in the cartridge.
A chip cartridge starts almost instantly but is only read. A cassette tape is slow but can also be written to.
A password has a check symbol to show that a letter was copied wrongly.

The console forgets as soon as the power goes off. And you — what do you write on paper so you do not forget?

Check yourself

1. Why did many games for the first consoles give a password?

because it is more fun because the consoles had no memory that remembers without power — the game gives a short code that you write down because the game wants to know who you are

2. What is the big advantage of a ROM chip cartridge over a cassette tape?

it starts almost instantly because it is read like memory it is always cheaper to make it holds much more than a floppy disk

3. Why does the game's password have a check symbol?

to make it prettier so that nobody can see it to show that a letter was copied wrongly

Skill badge: “I Save the Game”
It is yours when you can explain how a console without memory saves a game with a password and how it does so with a battery, and why a password has a check symbol. No points and no ranking — only a skill.

08I have a question

Do you still have a question? Write it here. It goes to your parent, not to strangers. Your parent confirms their e-mail first.

The form is loading… If it does not appear, write your question on paper and show it to a parent or teacher.

·Sources

Title: Games Come Home: Consoles and Home Computers (DB-IG-05) · Author: Children's Library, East Accelerator Foundation · Source: original content, 2026; the console “Circle”, the game and the password scheme are original code and design — no pictures, sounds, characters or recreations of real games · Rights: CC BY-SA 4.0.
Title: Magnavox Odyssey · Author: Wikipedia contributors · Source: en.wikipedia.org/wiki/Magnavox_Odyssey (checked 02.10.2026) · Rights: CC BY-SA 4.0 · Adaptation: facts only, re-told in our own words: the idea of August 1966, seven prototypes, the “Brown Box”, USA — September 1972, three dots and a line, no sound, no score keeping, dice and sheets, circuit cards instead of ROM cartridges.
Title: Fairchild Channel F · Author: Wikipedia contributors · Source: en.wikipedia.org/wiki/Fairchild_Channel_F (checked 02.10.2026) · Rights: CC BY-SA 4.0 · Adaptation: facts only: November 1976, the first with a microprocessor and ROM cartridges.
Title: Atari 2600 · Author: Wikipedia contributors · Source: en.wikipedia.org/wiki/Atari_2600 (checked 02.10.2026) · Rights: CC BY-SA 4.0 · Adaptation: facts only: “around September 1977”, nine games on 2 KB cartridges, 128 bytes of RAM, swappable ROM cartridges made common.
Title: ROM cartridge · Author: Wikipedia contributors · Source: en.wikipedia.org/wiki/ROM_cartridge (checked 02.10.2026) · Rights: CC BY-SA 4.0 · Adaptation: facts only: read like ordinary memory and an almost instant load; dearer and smaller than floppy disks; the Odyssey's boards as a forerunner.
Title: Saved game · Author: Wikipedia contributors · Source: en.wikipedia.org/wiki/Saved_game (checked 02.10.2026) · Rights: CC BY-SA 4.0 · Adaptation: facts only: early consoles without memory that remembers without power; passwords; battery memory in the cartridge (Pop and Chips, 1985; The Legend of Zelda, 1987); cassettes and floppy disks on computers.
Title: History of personal computers · Author: Wikipedia contributors · Source: en.wikipedia.org/wiki/History_of_personal_computers (checked 02.10.2026) · Rights: CC BY-SA 4.0 · Adaptation: facts only: Apple II, PET 2001 and TRS-80 in 1977 (the “1977 Trinity” per Byte); tape recorders in most homes; 300–1200 baud; errors; the price of disk drives.
Title: The Legend of Zelda (video game) and Metroid (video game) · Author: Wikipedia contributors · Source: Zelda · Metroid (checked 02.10.2026) · Rights: CC BY-SA 4.0 · Adaptation: only the release dates and the facts about saving: battery memory in the NES cartridge; reviews of the password (“tedious” / “very handy”).
Related lessons: DB-MD-04 “The Singing Tape” · DB-IB-01 “Passwords” · DB-RK-08 “Installing a Game” (age-rating signs and time). Retro articles on kagami.bg (in Bulgarian): Apple II · TRS-80 · Commodore PET · ZX Spectrum.
Our calculations: 128 bytes ≈ 128 characters ≈ two short sentences; 9 × 10 × 3 = 270 states; 32 × 32 = 1024; the check symbol (5a + 3b + 11) modulo 32 is our own scheme — we do not claim that real games used it.
Magnavox, Odyssey, Fairchild, Channel F, Atari, Apple II, Commodore PET, TRS-80, Metroid, The Legend of Zelda, Super Cassette Vision, NES and Nintendo are trademarks or names of their owners. They are mentioned only to make clear which machine or game we mean; the lesson has no connection with them and does not advise what to buy.
Licence: CC BY-SA 4.0 · Children's Library, East Accelerator Foundation, 2026. You may share and adapt this lesson if you credit the author and keep the same licence. Learning is free forever.