[CoCo] 720kb vs 1.4mb 3.5" disks

[Ray Watts]

Many years ago Marty Goodman wrote an article comparing the magnetic 
field intensity required to write to the different disks available to a 
CoCo user.  He recommended against using 3.5" HD (1.4mb) disks on the 
CoCo in place of the 720k DD ones.  His reasoning (if I recall it 
correctly) was that the HD disks were written to at a higher intensity, 
and therefore, if written to at the lower 720k intensity, would not 
reliably retain the data.

I have been using 3.5" 720k disks on my CoCo's for over 12 years, with 
bootable disks for over 11 years.  Occasionally, such as the old AOL 
givaways, I have possessed 1.4 mb disks.  Remembering Marty's article, I 
never used these disks for anything serious, just reformatted them to 
720k for use as "scratch" disks.  About six years ago I began 
downloading RTSI files onto HD disks.  Neither the scratch disks nor the 
RTSI disks have ever lost a file and I am beginning to feel that Marty's 
warnings were overblown.  My rationale for this is that the HD disks 
probably have a superior oxide coating and will accept the lower 
magnetizing intensity at the slower rotational speed much better than 
anticipated.

Have any posters experienced problems using 1.4mb disks on a CoCo 
formatted to 720k?  If so, was there any evidence of the problem being 
due to the magnetizing force?

Griz