Any idea about new commands for switch TRD images ? Each TRD image=640kB. If I select TRD number 120 then shift LBA position to BEGIN(first sector of first TRD image) to 120 x 1280 ide sectors. Can be used two new commands - one for set ABSOLUTE position(number) of TRD, next for set RELATIVE position(number) of TRD.

example:
NEW 10 = select disc 10 (absolute position)
NEW +4 = jump to 4th disc (if current position is 10 then after this command is position 14)
NEW -2 = jump 2 discs back

We must also after each NEW XX command save number of selected TRD disc(position). I can save it to IDE sector, but trdos must before each read/save trdos sector also read selected TRD position. Next problem is in IDE sector size - TRDOS use 256bytes sectors and IDE device use 512kB secotrs. Then if I need save only one sector to IDE, my code must as first load one half of ide sector(256bytes) to ZX ram and save it as new 512bytes IDE sector (orig.half of ide sector + new 256 trdos sector data). And where I can find free 256 bytes in ZX ram ? On stack ?(it's can be with some loaders unusable). In extra ram >128kB ?(will work only on clones with big memory 256kB and more).