Looking for something to do in quarantine? How about booting DOS from a 10-inch vinyl record?
While booting an operating system nowadays usually sees the software loaded from disk or flash memory, some of us of a certain age recall the delights of shovelling bytes in memory via the medium of tape, such as an audio cassette sending noise into the RAM of a home computer.
Tinkerer Jozef Bogin has taken things a little further by booting an elderly IBM PC from a record player.
Bogin used an old IBM PC and took advantage of a boot loader that would cause the hardware to fall back to the PC's cassette interface should everything else (floppies etc) fail. An analogue recording of bootable, read-only RAM drive was played through the interface, containing a version of FreeDOS tweaked by Bogin to fit into the memory constraints, a tiny COMMAND.COM and a patched version of INTERLINK to shovel data through the printer cable.
It's impressive stuff. To fit on a 10-inch vinyl record, Bogin had to cram everything in 64K, resulting in six minutes and 10 seconds of audio at 45rpm. While the warmer sound of an analogue recording might appeal to audiophiles, Bogin noted that the record had to be pristine and contain no pops or crackles. "However, some wow is tolerated, and the speed can be 2 or 3 per cent higher or lower too."
Those same audiophiles will be interested to learn that Bogin used a Harman&Kardon 6300 amplifier with an integrated phono preamp. "I had to fade the treble all the way down to -10dB/10kHz, increase bass equalization to approx. +6dB/50Hz and reduce the volume level to approximately 0.7 volts peak, so it doesn't distort. All this, naturally, with any phase and loudness correction turned off."
It's a glorious thing, and put this hack in mind of software turning up on records back in the 1980s. In 2004, Adam Kempa detailed some examples of the breed. Popster Shakin' Stevens gifted listeners with "The Shaky Game" on a vinyl release of his "This Ole House" single while the cassette version of The Stranglers' Aural Sculpture included a text adventure for Spectrum-owning fans to play.
As Bogin observed: "The cassette modem does not give a hoot in hell about where the signal is coming from." We're just glad he opted for the medium of vinyl. ®