It’s merely a ROM drive implemented in the BIOS. Drive 8 is used.
There’s also an INT 18h hook that operates by simply booting drive 8. This is the fallback bootstrap hook. No disks? No problem. Boots to DOS vs. IBM which booted BASIC or everyone else who just prints an error.
On one of these Tandy’s, DOS is really running from RAM, it is merely loaded from ROM, and even then it’s just a virtual disk.
There are versions of DOS that can be run directly from ROM, but this isn’t one of them.
Curiously, Deskmate runs from ROM for real. Meaning the code is actually running in the Exxx segment backed by the actual ROM chip. The Deskmate files on the ROM drive are relatively small and are only a small part. The bulk of the code runs direct from ROM.
It’s merely a ROM drive implemented in the BIOS. Drive 8 is used.
There’s also an INT 18h hook that operates by simply booting drive 8. This is the fallback bootstrap hook. No disks? No problem. Boots to DOS vs. IBM which booted BASIC or everyone else who just prints an error.
On one of these Tandy’s, DOS is really running from RAM, it is merely loaded from ROM, and even then it’s just a virtual disk.
I wrote a little tool to make the ROM drive accessible on non-Tandy DOS: https://github.com/dfelliott/tandy1000-romdrive
There are versions of DOS that can be run directly from ROM, but this isn’t one of them.
Curiously, Deskmate runs from ROM for real. Meaning the code is actually running in the Exxx segment backed by the actual ROM chip. The Deskmate files on the ROM drive are relatively small and are only a small part. The bulk of the code runs direct from ROM.