Jozef Bogin Boots an IBM PC From an Unusual Medium: A Vinyl Record
Taking advantage of the IBM PC's cassette deck interface and a vinyl cutter Bogin may now own the only IBM compatible to boot from a record.
Engineer Jozef Bogin has taken on an unusual challenge: Getting a computer to boot from a vinyl record, played at 45 revolutions per minute.
Today, most computer systems use magnetic or solid-state media for their storage — hard drives or solid state drives. In the early days of computing, though, cassette tapes were not uncommon — storing the digital data as audible beeps and boops which could be played back on any standard cassette deck. That link between audio and digital data gave rise to programs distributed on the flip-side of cassette albums, and in a few unusual cases programs which could be played back on the B side of vinyl records.
It's these latter distributions, which were uncommon at the time and have not become more so, that gave Bogin his inspiration: "Why don’t we try to boot from a record player for a change?
"So this nutty little experiment connects a PC, or an IBM PC to be exact, directly onto a record player through an amplifier. There is a small ROM boot loader that operates the built-in 'cassette interface' of the PC (that was hardly ever used), invoked by the BIOS if all the other boot options fail, i.e. floppy disk and the hard drive. The turntable spins an analog recording of a small bootable read-only RAM drive, which is 64K in size. This contains a FreeDOS kernel, modified by me to cram it into the memory constraint, a micro variant of COMMAND.COM and a patched version of INTERLNK, that allows file transfer through a printer cable, modified to be runnable on FreeDOS. The bootloader reads the disk image from the audio recording through the cassette modem, loads it to memory and boots the system on it. Simple huh?"
Things weren't quite so simple, of course: With no bootable vinyl records around, Bogin had to cut his own using a record-cutting lathe — and correct the signal before feeding it into the IBM PC. Likewise, the pops and clicks of a vinyl record needed to be filtered out to avoid bit-flips in the boot process. For those interested in hearing what the resulting record sounds like, Bogin has published a YouTube video — but you may want to turn your speakers way, way down before hitting the play button.
More details are available on Bogin's website.