Opening soon at atract.org

A home for what you make

Publish it, run it in the browser, review it, fork it: programs, packs, articles and art for the 8-bit Atari, made with open tools.

By the ATRACT author

On an 8-bit Atari, memory location 77 is called ATRACT. The operating system adds one to it every four seconds or so, and any key press puts it back to 0. When it passes 127, nobody has touched the machine for about nine minutes, so the OS starts shifting the screen's colours to save the TV from burn-in. That is attract mode, and this site is named after the byte that starts it.

It also spells what you do here: Assemble, Trace, Reverse, Annotate, Comment, Tinker.

What is coming

Publish: Programs, packs, articles and art you made, with their source and a licence that lets others learn from them.
Run: Anything published runs in the browser, on a free OS and BASIC. No ROM to look for.
Review: Comments that point at a line of source, a label or a memory address.
Fork: Make it yours. Changes are readable diffs, and can go back to the author as a suggestion.

Type-in program

POKE 77,0

Nine lines of BASIC that put a rainbow down the screen and keep your Atari awake: the program writes 0 to location 77 on every scan line, so attract mode never comes.

10 REM POKE 77,0 FROM ATRACT.ORG
20 S=0:FOR I=0 TO 25:READ B
30 POKE 1536+I,B:S=S+B:NEXT I
40 IF S<>2490 THEN PRINT "TYPO":END
50 X=USR(1536)
100 DATA 169,0,133,77,173,11,212
110 DATA 24,101,20,141,10,212,141
120 DATA 26,208,141,24,208,162,0
130 DATA 134,77,76,4,6

The two letters beside each line are its check, not part of it. Multiply each character's ATASCII code by its place in the line (1, 2, 3…), add them up, and divide by 676: the remainder, split into 26s, is two letters from A. A typing slip changes them, and so does swapping two digits.

What you will see: a rainbow of horizontal bands, one colour per scan line. — What you will see. The 26 numbers are the machine code of ATRACT's own demo, placed in page 6 (address 1536) and started with USR.

News from the workshop

The build log. Follow it with the Atom feed.

23 Oct 2026 A new face for this page: a computer magazine from the eighties, with a program you can type in, or let the page type it for you.
22 Oct 2026 The site can look like the real machines: the Atari's own screen and letters, the 65XE computer, or the 1050 disk drive, where each program is a floppy you slide in.
21 Oct 2026 Comment on any program, make your own copy of it, and offer your changes back to its author.
21 Oct 2026 Two names: atract.org in English and atract.cl in Spanish.
21 Oct 2026 Anyone can publish what they make, and a person looks at every upload before it appears.
21 Oct 2026 Programs run right in your browser, on a free stand-in for the Atari's own system. Nothing to install.