Int 31 Fn FF25  P - Causeway - "getdostrans" - Get Dos Transfer Buffer     [E]

   AX = FF25h

Return: BX = real-mode segment of transfer buffer
   ECX = transfer buffer size
   DX = protected-mode selector for transfer buffer

Note:  the default buffer size of 8K is sufficient for most applications,
     but an application performing large amounts of file I/O may benefit
     from allocating its own, larger buffer

See Also: AX=FF00h,AX=FF26h