Most PCs tend to boot from a primary media storage, be it a hard disk drive, or a solid-state drive, perhaps from a network, or – if all else fails – the USB stick or the boot DVD comes to the rescue… Fun, eh? Boring! Why don’t we try to boot from a record player for a change?
64 512 byte DOS boot disk on a 10″ record, total playing time 06:10 on 45 rpm
Update February 2022: Click here to observe the very same vinyl ramdisk booted on an IBM PCjr!
The vinyl loader code, in a ROM
And now to get more technical: this is basically a merge between BootLPT/86 and 5150CAXX, minus the printer port support. It also resides in a ROM, in the BIOS expansion socket, but it does not have to. The connecting cable between the PC and the record player amplifier is the same as with 5150CAXX, just without the line-in (PC data out) jack.
Bootloader in a ROM; being an EPROM for a good measure
And that’s it! For those interested, the bootloader binary designed for a 2364 chip (2764s can be used, through an adaptor), can be obtained here. It assumes an IBM 5150 with a monochrome screen and at least 512K of RAM, which kind of reminds me of my setup (what a coincidence). The boot disk image can be obtained at the bottom of the BootLPT/86 article, and here’s its analog variant, straight from the grooves 🙂