Re: RF74 Disk

[Paul Koning <paulkoning%comcast.net@localhost>]

> On May 6, 2025, at 12:57 PM, Andrew Ball <asbatwrk%gmail.com@localhost> wrote:
> 
>  ASB> Since I'm making virtual disks for open-simh, I'm probably just
>> looking for a total number of sectors (especially for the RF74)
> 
>   PK> Does it matter?  If those disks are connected to MSCP
>> controllers, the host just sees a vector of blocks, and the
>> device geometry is irrelevant and invisible.
> 
>    It's not critical but the completionist in me would love to know
> that the disks I create in the emulator could be dumped onto their
> physical counterparts and not hang off the end.

Yes, that's what you'd expect from emulated disk container files.  But that will be true so long as the sector count matches, given that you'd just be using dd or equivalent.  If you were actually using at the physical device at the physical recording level you'd likely see all sorts of other stuff not visible to software, like spare sectors, block remapping, and fun stuff like that.  If you were building a plug-compatible RF74 emulation (a device that could plug into an RF74 controller) you'd have to worry about that, like David Gesswein's famous MFM disk emulator.  But for virtual disks you see none of that.

	paul