86-DOS 1.00 on VirtualBox
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Author:  SebOno [ Thu Feb 06, 2020 9:23 pm ]
Post subject:  86-DOS 1.00 on VirtualBox

86-DOS 1.00 can usually be run using a special Z80 emulator.
But, it can actually run on VirtualBox, VMware, Microsoft Virtual PC or similar software.
The way I did it is that I first installed MS-DOS 5.00 and the MSCDEX CD-ROM drivers.
Then, using the VISO functionality of VirtualBox, I included all 86-DOS system files.
To install it, I wiped the C: drive then copied all files from the hard drive to the hard drive.
The next reboot, I got greeted by the 86-DOS COMMAND.COM application, working on VirtualBox!
Here is the proof:

Note that when I booted it up, it didn't ask me for the date like it does on the Z80 emulator.
(This is just a basic experimental attempt. If anyone can tell me of a way to get a PC-compatible version of 86-DOS working, that would be great)

Author:  ComputerHunter [ Thu Feb 06, 2020 10:25 pm ]
Post subject:  Re: 86-DOS 1.00 on VirtualBox

That is such a bad idea because 86-DOS 1.00's BIOS and kernel are stored on the reserved sectors of the 8" floppy (so they are not files) and you are basically using MS-DOS 5.0 with 86-DOS 1.0's COMMAND.COM. Also, the DOS kernel asks for date in very early versions of DOS, not COMMAND.COM.

Author:  JustZisGuy [ Thu Feb 06, 2020 10:28 pm ]
Post subject:  Re: 86-DOS 1.00 on VirtualBox

You could not have included 86-DOS' system files because 86-dos 1.0 did not have system files. The system resided in a set of reserved sectors at the beginning of the disk, like most CP/M systems.

The application level/user programs like or edlin are fairly "well behaved" DOS programs that use APIs still supported in later DOS. These are known to run under later DOS and Windows, including Windows 10-32bit NTVDM.

Author:  ComputerHunter [ Fri Feb 07, 2020 7:53 am ]
Post subject:  Re: 86-DOS 1.00 on VirtualBox

Technically 86-DOS 1.00 do have system files but they were written to those reserved sectors on the floppy disk (before the FAT begins). It is possible to extract them and with a later version of the BIOS (1.10), you can actually make a bootable disk with 1.00's kernel stored as a file. 86-DOS disks and MS-DOS disks are incompatible because of those reserved sectors so I have no idea how he managed to copy those 86-DOS files to his MS-DOS installation (unless he extracted them to his host computer and inserted them to his VM).

It is not entirely impossible to create a working version of 86-DOS for VirtualBox and VMware (so PC-compatible) but is does require you to rewrite the boot sector and BIOS. The kernel also needs to be patched if I recall correctly. Running COMMAND.COM on MS-DOS 5 does not mean you have 86-DOS since the kernel is not 86-DOS's.

Author:  vbdasc [ Thu Feb 13, 2020 9:25 pm ]
Post subject:  Re: 86-DOS 1.00 on VirtualBox

I don't think 86-DOS can be run on a Z80 emulator, unless SIMH AltairZ80 is meant, which is not only a Z80 emulator, despite the name.

Author:  ComputerHunter [ Thu Feb 13, 2020 10:13 pm ]
Post subject:  Re: 86-DOS 1.00 on VirtualBox

Yes it can (on AltairZ80). It does simulate 8086. It only support the Cromemco 4FDC floppy controller if I recall correctly. For 86-DOS 1.14, you have to assemble the boot sector and DOS BIOS with the Cromemco switch on and hex-edit the floppy image for it to boot on the AltairZ80 simulator.

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