Bit of CP/M trivia needed - test-drb@ccmp.vtda.org

29 Aug 2005

...
 From: "Allison" <ajp166 at
bellatlantic.net>
 ---snip---
...

The DSD880 and RX01/02 drives are of a similar design with a local 
CPU (crude TTL logic state hardware or 2901s) to do all the heavy
lifiting at that floppy interface end with a trivial interface 
to the processor bus.  Neither include boot logic.

As to DMA on FDCs well SMC did one that had it but it was a PITA
to use as every bus is differnt and timing plus control signals 
required a lot of work to integrate.  Most FDCs were trying to be 
generic and to keep die size down (hence cost) things were not
done that would make the chip system specific.  ---snip---

Hi Allison
 It is interesting that they didn't include this.  
On my machine it isn't even more hardware. There
is just one instruction in the state machine to
load a sector count of 1. It then just does a normal
read. Every thing else is just default reset values
...
 from the reset line. I remember thinking how trivial
it was. I can understand that if the controller needed
to know things like density, this might require more
but it is a simple operation that could be easily
added to any that have a state machine to run
the controller operations. I can see why the FDC
chips don't do this. There is a lot to setup but
still, a default reset state could have easily
provided the needed inital values.
 As I recall, the board has a jumper to not do the
auto boot. I think the auto boot is a cool thing.
Also, yes it is rare.
Dwight