30 years later, a lost Days of Thunder NES game recovered from 21 floppy disks

In one of the most unreal data-recovery projects we've ever heard of, a seemingly lost NES game has been unearthed—as archived on a single hard drive backup, spread across 21 5.25-inch floppy disks.

A joint effort led in part by the Video Game History Foundation began earlier this year with a pile of leftover CD-Rs, floppies, computers, and other errata donated by the family of late programmer/designer Chris Oberth. The results, thus far, are one fully functioning game whose code had to be recovered, then compiled, to run on original NES hardware.

Anybody still have their copy of PCTools?

The game in question is based on Days of Thunder, a stock-racing film from 1990 starring Tom Cruise. One reason this version got lost in the shuffle is because a tie-in DoT video game came out the same year, as published by Mindscape. Oberth's co-creation, for the same publisher, was dated one year earlier, and it looks quite different. As Frank Cifaldi, VGHF co-director, points out, the unreleased prototype had only been mentioned once by Oberth: in a 2006 interview with the retro-gaming fan newsletter Retrogaming Times.

While trying to recover other lost games from the designer, the archival team noticed a single disk labeled "NINTENDO: HOT ROD TAXI, FINAL." The recovered prototype from this disk turned up a playable "early proof-of-concept" project about cars driving through a city, but its existence, and a brief guess that it was somehow related to Days of Thunder, was enough to focus the archivists' search on other disks for anything that might need coddling to work on an NES.

That guidance paid off when the team located a 21-disk archive of a single hard drive (conveniently labeled: "PCTools 5.10 Backup"). Miraculously, all 21 disks could be read, and initial attempts to read the archive turned up a file directory with hints of Days of Thunder. Eventually, VGHF's team used an era-appropriate computer to load PCTools in native MS-DOS, which allowed them to extract a jumble of files.

Instead of a ready-for-gaming ROM, archivist Rich Whitehouse found the source code, along with most of the game's data and its assembler, in a single directory. In VGHF's Monday post, Whitehouse chronicles the pains he went through to find a few key pieces of data spread elsewhere on Oberth's hard drive backup, particularly a set of "tiles" (as in, static pixel art that the NES renders and cycles through) needed to display the game's graphics. This file was quite elusive, and he writes:

I extracted every archive in every known format in every one of the drive backups, and did the same for every other disk image that we’d managed to recover. I ran another search over the whole thing, and there was a single hit on a 128KB binary file. Oh yes.

Make your own, or buy your own

Without that successful file recovery from "a seemingly unrelated set of data," Whitehouse and friends say they would have either lost the game forever or been forced to author their own assets and estimate how it was meant to look. "Every floppy matters," Whitehouse writes.

Instead, they've uncovered a simple-yet-playable racing game focused on the stock-car experience: a qualifying driving run with a 3D effect and zero other cars on the road, and a 2D approximation of a traditional, crowded race. Mindscape's eventual Days of Thunder game included more 3D-perspective trickery, which may be why it won out as the tie-in game to reach store shelves.

Yet, in spite of the data recovery missing portions of the game's source data, VGHF has decided to upload everything its engineers used to author and publish the ROM to a Github repository so that interested users can learn from the available code and produce their own versions of the discovered ROM. (Update, 1 pm ET: The Github link is still not live as of press time, but VGHF says it's coming "soon.") Should retro gaming enthusiasts want to memorialize the lost game in more polished fashion, they can now order working cartridge copies of the game—with all sales proceeds going to Oberth's family.

It's a big data-recovery win for a project that began with hopes of finding Oberth's better-known lost games, particularly when he worked on arcade games for Stern; VGHF is still seeking information on recovering those games, or any other lost software, and its archivists will happily accept your tips (and seemingly destroyed disk backups, because, hey, who knows).

Listing image by VGHF / Chris Oberth