[Coco] Booting OS9 on my CoCo 3

Dave Philipsen dave at davebiz.com
Tue Aug 8 03:11:22 EDT 2017

Ok, so it's been a REAL long time since I booted OS9 on my real CoCo 3 
from a floppy disk.  Like almost thirty years.  So I picked up a used 
FD501 controller from eBay awhile back and I just now hooked up a 3.5" 
floppy to it.  I can format a floppy and I can save/load programs from 
it.  But when I try to boot an old disk (probably 30 yrs old) I get the 
familiar "OS9 BOOT" screen and then the floppy does a seek at what 
sounds like a faster step rate and then it does nothing.  Frozen with 
"OS9 BOOT" on the screen and the floppy is still selected with the motor 

This is a very old boot disk that I labeled "OS9 Level II System Master 
with ramdisk".  My old setup was a CoCo 3 with 512K and a multipak and 
one of the old full-size floppy controllers and an RS232 Pak.  My new 
setup is a CoCo 3 with 128K, no MPI,  the FD501, and a 63C09.

I've got some 5.25" OS9 disks too but I don't currently have a 5.25" 
drive so I'm hoping to get things worked out with the 3.5" drive. It may 
be that the floppy is just so old it's lost some of its retentivity but 
I just thought I'd put it out there to see if anyone has an idea.  Maybe 
I'm missing something obvious.  The FD501 does not seem to work at 
hi-speed. Could that be the problem?


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