I was sent this link while out for vacation: https://github.com/retrohun/blog/tree/master/dt/bootingfromcom1
So this is great for machines that included the seemingly useless ‘casette basic’ as you could maybe shove over something to config the machine, maybe ‘rom dos’ directly into ram to fdisk/format without using disks… Interesting stuff to say the least!
Actually, the pasted screenshot is a bare “CAS1:” booting and merged into a Galaxian splash. The serial boot is similar, but instead of using LOAD, needs 2 lines of basic code with injected machine code into DATA line(s).
Anyone is kindly welcome to shorten the basic loader, improvement ideas etc.
Also it is worth mentioning that crap PS/2 quality boards and their ridiculous HW configuration data are usually getting lost in decades and/or integrated storage controllers might have damage. In such case, a rom basic would be handy 😉 Even just for reprogramming the NVRAM – also keep in mind that their CMOS layout differs from ordinary IBM WC compatibles 😛
I am working on a serial/lpt/cas bootable rAm-dos (2.11+ based)
A similar system exists for the Apple II called ADTPro. It can be bootstrapped from Applesoft BASIC using either the cassette port or a serial port. Once up and running, you can transfer disk images to real disks on the Apple II. Very handy for getting a system up and running when you don’t have any boot floppies.