*)u wont command it using the standard IDE/SCSI , those DiskOnKey all implements a standart command set written for them especially. this command set let windows "removeable storage" driver to communicate with it so to the layer(in windows ,not the flashKey) above , it looks like a normal drive. FAT/32/NTFS is a matter of how does the layer above decides to format it. (though there might be limitation cause u need several drive characteristics in order to format NTFS).

*)implementing a USB **HOST** in a 51 is not achievable in my opinion. i dont know if u ever read USB "rfc"... but , USB is a protocol with a lot of descriptors, string descriptors , high bandwidth and lots of buffers ,not something u ll keep in a 65K addr space, and even if it is possible , its not something you want to get into...

i saw one diskOnKey (cyberKey corp. if i remember correctly) which simply took samsung flash , cypres EZUSB and thats it. so all they had to do was to imlpement the client side of the standard "Removeable-Storage\USb-Drive". driver which is installed on every windows(thats y you dont have to carry an installation CD with u).
so - you will have to implement a host , and the "windows" RemStorage driver above it. how do you guys(erik?) plans on putting that on a 51?


*) as for modifying the flash directly... most DisOnKey devices i saw uses Samsung Flash IC , which is connected using Muxed-bus or some other bus implementation , but not serially , so interfacing with it will be a nifty thing to do , also , this is not something that is designed for a "hot-swap" so you cannot do frequently ... not to mention while power-up.