"CP/M compatible" vs. "MS-DOS Compatible" machines?

[Joshua Alexander Dersch]

scheefj at netscape.net writes: 

> In the early-mid 80's a program was "well behaved" if it did it's I/O thru 
> DOS calls. Those programs would run on just about anything.

Were there similar problems in the CP/M world?  That is, was it commonplace 
for there to be CP/M programs that bypassed CP/M BDOS calls and wrote 
directly to a specific machine's hardware?  Seems like CP/M developers were 
more disciplined in this fashion, but maybe it's just because in the CP/M 
arena there were so many different pieces of hardware it was the only way to 
do it?  (Whereas with IBM, the PC was seen as more of a reference standard, 
even if it wasn't really that way in the beginning?) 

I'd be interested to hear opinions from people who were there at the time, 
since it was a little before my time. 


Josh