The Microbee was an early '80s Z80 microcomputer from Australia that was successful mostly in education.

Looking at some disk image files I've downloaded I can see the disk layout seems to be very similar the Amstrad CPC and Sinclair ZX Spectrum +3 derivatives of the CP/M disk layout. In fact the same DSK disk image format is used.

I can see these disks have a Z80 boot sector in the first sector. But I'd like to know where in RAM this code is loaded and executed.

The boot sectors I've looked at refer to a few addresses in the low 0xE000 range, but they don't align with instructions in the boot code, assuming the sector is loaded at a 16k boundary, which might be a false assumption. Otherwise those could be ROM addresses but so far I can't find any of them referenced on the Internet. (Yes the boot ROM does reside at 0xE000 I can now confirm.)

Info on the technical workings of these machines is scant on the internet and I can't get any of the emulators to work, or at least not with disk support.

Does somebody know where the Microbee loads the boot sector from disk?

  • You may try an emulator like uBee512. – Polluks Jul 22 '20 at 14:04
  • @Polluks: Yes I have that and I think Nanowasp and MAME and can't get any of them to work well. I had uBee512 working finally a few times and then it started ignoring whatever disk I tried to boot from and now only boots from the same, possibly internal one? – hippietrail Jul 22 '20 at 14:09

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