_ DEC-O-LOG for UDA50

_ DOL, UDA50-R0005, UNIBUS Disk Adapter AUG 84

PROBLEM: UDA50's may detect "INTERRUPT TIMEOUT', and the VMS may 
"hang" for the 5-10 seconds on the VAX-11/750's with CI750 or DR750's 
(also possible on other configurations).  This is due to inefficient 
"INTERRUPT' handling by the UBI/L0004 (or DW750/L0010) and an 
insufficient "INTERRUPT TIMEOUT' period in the UDA50.  The ERRORLOG 
message reported will be "RING READ PARITY ERROR/TIMEOUT". 

CORRECTION: Change the Unibus Disk Adapter, as well as all the 
supporting Documentation from the Shielded to the Unshielded
SDI Cable. 

IN-PLANT EFFECTIVITY: NOV 84 

FIELD EFFECTIVITY: Applicable ONLY to UDA50's installed on the 
VAX-11/750 Systems.  Retrofit UDA50's installed on the VAX 11/750 if 
the CI750 or a DR750 is present, or if problem symptoms are evident, 
to the following minimum revision:
M7485-YA (Microprocessor) - Revision "H1".  Retrofit spares stock to 
the above minimum level. 

QUICK CHECK: Check the M7485-YA module for the presence of PROM 
(23-184F4) in location E16. 

The DEC on-site labor charge will be the time required to install and test
the FCO at the then current hourly rate. 

FCO KIT ORDERING: 

EQ-01239-01: FCO, PARTS
EQ-01239-02: FCO, PARTS
FA-04509-01: FCO only