[Simh] Raw access to disk/cdrom devices

[Tim Shoppa]

> I already tried to use /dev/sda as the target device and found out that it
> didn't work...that's part of what started me thinking about how to make it
> work. :)

The last time I looked at this under linux I came to the conclusion
that the stat(2) call on the raw devices didn't necessarily return
the values I would naively expect.  In particular the device
size is hard to get at portably in this naive way.  Put
a couple #ifdef's for various systems and maybe it's not so
bad... but I haven't tried to write this portably.  I've
got access to linux and VMS readily, and BSD and Windows not so
readily.

I think that the stat(2) call on BSD did return what I expected
for raw device size (at least up to 4 Gbytes).

I think raw native tape access would be nice someday too.

Approaching this with a "SCSI mindset" might work but may not
be the most portable way.

Tim.