[CoCo] 720kb vs 1.4mb 3.5" disks

[Roger Taylor]

At 02:36 PM 12/10/2003 -0800, you wrote:
>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?


My CoCo's drive 0 is a 1.44meg 3.5", so I use the HD disks with a small 
sticky tab over the left hole so data gets written/read at the DD config.

I have always heard not to put HD disks in a DD drive because of the 
difference in thickness of the disk surface, although before I knew this I 
had done this many times.  Every single one of my DD and HD 3.5" floppy 
disks are error-free to this day and I've been known to use them in various 
drive types from time to time.

My main problem has been with sand or grit getting onto a 5.25" disk 
surface and just scratching the hello-world-of-assembly out of the disk, 
damaging the data on it.  I've got a handful or two of physically damaged 
5.25" floppies that I save for some reason.  Now, I have an old friend who 
tickled me to death one time after he took a can of cleaning spray and 
soaked a bunch of his floppies that were on the table.  He just picked them 
up one by one and gave them a big squirt on the front and back, sit them 
back down and waited for them to dry.  Then he used them in the drives, 
ofcourse, or I wouldn't be telling the story.  He was drunk.  His floppy 
disks survived.

As for your thoughts on the overblown warnings... I see similar warnings 
and scares all the time.  Some people are just overprecautious and if 
they've got a magazine spot read by thousands of people, then the idea 
spreads like wildfire.  Marty is a good man and I have always trusted his 
words.  However, there's other people who dream stuff up based on their own 
fears.

For instance... I use Windows XP.  Occasionally, and rarely, a beta version 
of a popular e-mail program will just freeze up while downloading e-mail, 
usually when other program is hogging the CPU.  My DVD also sometimes won't 
spin back up or it takes a while to decide to spin back up if I'm running a 
certain multimedia program.  If I'm using several of these programs at the 
same time and the system decides to go into a deadlock on me, and I sit 
there for 10 minutes giving all the patience I can, and still... 
nothing.  I simply hit the reset button.

God forbid anyone ever hit RESET on a PC, right?  It could damage the hard 
drive, right?  Well, sure... about 20 years ago the HD heads just sat right 
down on the surface if you killed the power, but ever since the dinos 
roamed, hard drives are quite smart devices that always react promptly and 
safely to a loss of power.  IT'S WINDOWS that throws the scare on you when 
you reboot, because it KNOWS it was not shut down properly, so it goes 
through this whole mess of hard drive scanning and file verifying.  Not 
once in years have I ever had a HD crash because I pressed the reset button 
on any computer of mine.  I have also had to pull the cord on my laptop way 
too many times (running Windows 98, mind you).  And my 3 year old boy has 
crawled under my desk many times and hit the little red power button on the 
emergency backup box, just shutting down everything.  Still, no sector damage.

My general rule:
If you know a few dinosaur scare stories, try not to pass them along to the 
people using modern technology if you can help it...


----------
Roger Taylor


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