[sebhc] Soft or Hard - why not go virtual?

Jack Rubin jack.rubin at ameritech.net
Wed Jun 30 17:55:46 CDT 2004

>  I don't expect to make a new disk controller for
> my H8. I expect to be able to use the H17. This
> is just an alternate way of dealing with these
> things.
>  We'd like to keep with the images that were 
> intended to run under the hard sectored machines.

>  The INIT command for hard sectored would not
> work for the soft sectored as an example.
> The editor might work in both.
> Dwight

Most "normal" programs really don't care how they get loaded into system
memory; thanks to HDOS' modular nature, you just need to have the proper
driver loaded (SY.DVD, DK.DVD) to handle disk I/O as required by your
hardware. Obviously CP/M does the same thing, though slightly less
elegantly, through BIOS customization (automated with the CONFIGUR
program). The only HDOS programs that I know of that are hard-coded to
the disk hardware are the INITxx commands that Dwight mentioned and the
various disk exercising programs (TEST17, TEST37, TEST47, etc.)

However, if the object of the discussion is to find a way to use the H17
controller and not worry about finding hard-sectored diskettes or
modifying current drives, the solution already exists in Eric Rothfus'
SVD box - http://www.rothfus.com/SVD/ - which electronically emulates a
hard-sectored drive with diskette. The box has an edge connector that
plugs into the floppy drive cable coming off the H17 controller; it
looks just like a drive with a diskette in it to the operating system.
The trick part is that the SVD box is in turn connected to a Windows or
Linux host which serves as an unlimited source of "virtual" hard
sectored diskettes. These disk images can be edited at the file level
and can be bootable; the SVD can be used standalone (one box can emulate
3 drives, though current memory capacity limits the number of disk
images that can be loaded simultaneously to 2)or in series with real
drives. The SVD uses the same disk image format as 2 out of the 3 Daves'
emulators (.h17), and images can be easily converted back and forth
between .h8d and .h17.


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