Interrupts and loading from disk

Hi all, I'm working on a C64 project which uses timer B on CIA2 to trigger 
a NMI at a 1kHz rate. I seem to remember that disk access tromps on 
interrupt handling as the C64 bit bangs the serial I/O to the drive. I have 
been searching and have not found a good in depth explanation of how this 
works and what might be done to work around it.
  
 Any links/tips appreciated.
  
 Jeff_Birt