One of the greatest joys of being a technologist is that I get to see, often first-hand, some of humanity’s most novel ideas. Technology, especially of the electronic kind, has been the vanguard of human innovation for at least a couple of decades — and so, really, we shouldn’t be surprised when someone does something unexpected with a computer. Case in point: One enterprising hacker has taken a TRS-80 — one of the first mass-produced personal computers — and given it the ability to stream an episode of Doctor Who from a stack of 5¼-inch floppy disks.

Really, before you proceed, you should just watch the video. Once you’ve picked your jaw up off the ground, I’ll walk you through the (crazy) details.

First, the numbers. The PC in the video is a TRS-80 Model 4P, which first went on sale in 1983. TRS stands for “Tandy/Radio Shack” — the company that made the PC, and the store that sold them. The 80 refers to the Zilog Z80 CPU — an 8-bit chip designed by Intel alumni Federico Faggin and Masatoshi Shima (they designed the original Intel 4004 CPU, then left to form Zilog). In the case of the Model 4P, there is a Z80A CPU clocked at 4MHz and 64KB of RAM — and of course, vital for this particular stunt, two double-density 5¼-inch floppy disk drives. Each disk could store a maximum of 180KB of data — so the entire audio and video stream is 720KB or less.

More importantly, though, how did the guy find enough bandwidth and processing power to get a 4MHz PC to play a 30-second video? (At 25 fps, no less! And with semi-decent audio playback.)

gp2000 ), it’s simply a matter of efficiently using all the resources available to him. The resolution of the video is 118×48, which equates to roughly 1KB per screen. The floppy drives (only one can be active at a time) can read a byte of data every 32 microseconds, giving a max theoretical bandwidth of 30.5KB/sec — so, 25 fps is possible, with bandwidth to spare. Gp2000 says the program that plays the video works in 32-microsecond steps; 13.5 microseconds are dedicated to reading data from the disk, with the remaining 18.5 microseconds spent decoding the data, drawing the screen, and driving the speaker. (The audio, incidentally, is 31250Hz at 1-bit per sample — which would usually be used for simple beeps and bloops, but can just about be coerced into playing music.) The two separate threads communicate via a 32KB ring buffer.

All in all, the TRS-80 streams the intro of Doctor Who surprisingly well from four floppy disks. There are a few glitches — perhaps caused by slight variance in floppy drive speed or corrupted data — which result in the screen displaying audio data and the speaker emitting graphics data, but it’s not bad for a 31-year-old computer.

Ultimately, you probably wouldn’t want to watch an entire episode in this way — you have to slot in a new disk every seven seconds, otherwise it crashes — but it’s nice to know that the option is there if some kind of worldwide catastrophe knocks out both YouTube and Netflix.

Now read: Is PC obsolescence obsolete?