DOS 3.3 RWTS question

[ck21062@uxa.cso.uiuc.edu (Greymalkin )]

I need to write a small routine in DOS3.3 that will read and write sectors from
disk except all my books and notes are at home.  From what I remember, you jump
to the DOS RWTS routine which reads parameters from the IOB included just after
the jump.
 
 JMP  RWTS  (something like $B600)
 IOB DATA   (read or write, buffer, slot #, drive, track, sector)

The machine routine is something like the above.  Could someone please fill me
in on the format of the IOB and the RWTS jump location?  Thanks.

Greymalkin