I am working on embedded Linux Video demo platform that utilizing a microdrive drive. Most of the playbacks are fine, but we noticed that there are some intermittent frame drops on some scenes while playback a Divx movie clip. I tested on a CF flash with the same media clip and it worked fine.
We are suspecting there is something to do with data buffering latency due to the physical properties of the microdrive, for example: seek time. I presume that this behavior happens on an IDE drive as well.
We planning to overcome this problem by implementing a Software HyperCache method, which will do our own buffering on the on board RAM. I am responsible to research and come out with a benchmark how much the caching will help on improving the data transfer.
If have done this and don't mind sharing this, please feel free to contact me to discuss further.