X3T9.2/89-102
                                                August 7, 1989





Mr. John Lohmeyer
Chairman X3T9.2
NCR   MS21
3718 N. Rock Road
Wichita
KN 67226


Dear John,

Tom Wicklund brought to my attention a boo-boo in the documentation of 
Synchronized Spindles in the ESDI document.

At present Table 30 (in 7.18.4) and Section K.3 (Annex K) reflect the 
following for the bit settings of setting synchronization mode:

   |               | 1   1   0   0 | Set Synchronized Drive            |
   |               |               |        x'00' = Slave              |
   |               |               |        x'01' = Master             |
   |               |               |        x'11' = Master Control     |
   |               |               |        x'80' = Unsynchronize      |

The Master Control is incorrect - it should have been x'03'. All other 
values in the table are binary, so I have modified the master documents as 
follows to correct the error.

   |               | 1   1   0   0 | Set Synchronized Drive            |
   |               |               |    0000 0000 = Slave              |
   |               |               |    0000 0001 = Master             |
   |               |               |    0000 0011 = Master Control     |
   |               |               |    1000 0000 = Unsynchronize      |

We should let the membership know of this, as it is possible that some 
companies implemented to the intent, and others to the error. 


                                                  Yours sincerely,




                                                  I. Dal Allan