TIS-100: What It Tasted Like

by Lucas Vially

MIT students crammed in a lab, a phreak manipulating tones, an enthusiast toying with a newly built mail-order microcomputer...  The early hacking experience is a thing of the past.  Nowadays, mysterious and groundbreaking systems are hard to come by.  Computers are more complex, yet the abundance of documentation and available products can, ironically, make it seem like everything has been mapped, created, discovered.  But it's still possible to live what it was like to tinker in the past.  You just have to simulate it.

The TIS-100 is a computer from 1972.  It has a unique architecture which can be mastered with nothing but a keyboard and its screen, displaying nuances of gray and white on black plus some occasional, alarming red.

It is also a fictive creation, actually released in 2015.  It was created by Zachtronics, a video game developer known for Infiniminer - the game which would come to inspire Minecraft - as well as for its many engineering-oriented programming games.  But while the computer and story it tells are fictional, the work you're about to do is as real as it gets.

The name of the TIS-100 is reminiscent of early computers such as the PDP-1, which had the habit of combining an acronym and an identifying number to make up their names.  Here, TIS stands for Tessellated Intelligence System.  While Intelligence System doesn't need to be explained, Tessellated comes from Latin's tessela, a piece of paving, tessalation being a synonym of tiling.  And so, our Tessellated System is filled with identical shapes, displaying a 4x3 grid of squares representing interconnected nodes.  Each node can hold one value, plus another one in backup.  Each node can contain up to 15 lines of code used to process and move values from a program's input, between adjacent nodes, and to the output.  The game offers challenges disguised as corrupted segments of the computers' programming, requiring to be rewritten.  You might have to multiply values to sequence a set, or, later, to handle series of numbers to be interpreted as an image in the visualization module.  The virtual device offers low-level programming with a minimalist assembly language, ready for you to tackle.

But before you get to that, the first step in playing is printing out the TIS-100's manual.  Fourteen pages detailing architecture, ports, instructions, and more.  The manual is presented as a copy of the original, now containing notes, highlighted passages, as well as scanned staples and hair strands.  It doesn't only instruct you.  It lets you know you're inheriting a mysterious computer, it gives it history and makes it seem more real.  It lets you role-play, making the upcoming experience feel more real.  In a 2015 Gamasutra interview, Zachtronics founder Zach Barth stated that "[TIS-100 is] designed to draw together sensations of a specific cultural experience - what it sounded like, felt like, tasted like, to be a computer hacker - and use them to tell an interesting and cogent story."  And many of the game's details work, beyond the surface, towards creating that genuine experience.

With limited computer memory, it used to be best to write programs concisely.  Shaving a few lines off was a practice required for effectiveness.  In TIS-100, the limited lines in a node can push you to do just that.  And while it isn't too hard to properly fit your code into each node, the competitive mind can be your next motivator.  Whenever you complete a level, you will get the stats of your program, and of other players'.  In how many cycles did it run?  How many nodes, how many instructions were used?  There's something to finally finishing a working program, to end your struggle, and find that others made it ten times more efficiently than you.  It's a push to try and rewrite your program, to optimize, to discover what you didn't imagine was possible.  It's finding out that your messy code can be made beautiful, and choosing to seek that beauty.

Back when the only computers were massive machines, nobody had one for their private use.  Most hackers would wait for their turn in a university lab.  When they had to leave, they could only wait for their next go at the machine.  Or, at least, they could prepare it.  With a pen, paper, maybe with a printout of what they had already programmed, they wrote more code.  Before they got a free time slot and traveled back to the lab, they had time to make corrections, and hope that everything would run smoothly.  The instruction set and system architecture of the TIS-100 are simple, enough to solve them the analog way, by scribbling a few squares and filling them with text.  While puzzles can be hard to solve, their rules always are straightforward, a few easy-to-remember sentences.  I have occasionally solved puzzles on the go, writing code in a notebook, executing it in my head.  I would test it hours, maybe days later.  In a way, this wait was still part of the experience: I got to look forward to when I would copy the code to my computer, to the excitement when the program finally runs.

From the dawn of computer hacking, there's always been unexpected creations.  The IBM 704 had a panel filled with rows of lights which students used to create a primitive ping-pong game.  The TX-0 played sounds based on the data it read, prompting the creation of a music compiler.  The TIS-100 too, you learn as you play, might be more powerful than you first suspected.  While the instruction set and system architecture are simple, there is a depth in the possibilities.  To some, the game is just a tool to learn how to use the TIS-100 so they can then write their own programs and really push its capabilities in new ways.  It has been used to create simple visual animations.  Somebody made a drawing program.  Someone else recreated Pong.  And you might find another way to push the system's limits.

Nowadays, computers are expected to be able to do any and everything.  And so, their surprises become less surprising.  But TIS-100 lets you discover a device which doesn't offer itself easily, which can do more than you would have suspected.  It might not have an actual practical use, but that only makes it a better reproduction of the early hacker experience: playing with a computer is enough.