Archiving Software

Dave Dunfield dave04a at
Fri Dec 16 11:15:41 CST 2005

> Dave, assuming you're reading this, how does ImageDisk talk to the hard disk 
> (for saving/loading images) and to the screen? Does it use DOS system calls, 
> or BIOS routines, or talk to the bare hardware?

For the FDC - I talk directly to the hardware, including the DMA chip - but I let
the BIOS handle the FDC interrupt (the handler just sets a flag indicating that
the current DMA operation if finished).

For the video, I talk directly to the video memory for individual character writes,
scrolling and for opening/closing text windows, however I use an INT-10h BIOS
call to position the cursor. (This is the text windowing library which is supplied
with the library for my Micro-C/PC compiler, and I use it for "all kinds of stuff",
and have never had a problem running under any version of winblows or

The any file access, it's via standard INT-21h DOS services.


dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools:
com             Collector of vintage computing equipment:

More information about the cctech mailing list