Technical data

Utilities (T 74 and T 76) 23
Table 3–5 (Cont.) PV_SCS_FMT_ERR# Error Codes
Error
Code Description of Code
6C Unexpected msg out phase
6E Too many retries of this command, failed after bus_device_reset
70 Timeout waiting for bus free after command (req is set)
72 No interrupt request for the dma in phase
74 SCD_CNT not zero following dma in phase
76 No interrupt request for the dma out phase
78 SCD_CNT wrong following dma in phase
7A Phase did not change soon after data xfer in phase
7C Phase did not change soon after data xfer out phase
82 Parity error on SCSI bus
84 SCSI req was not set in time
86 SCSI req was not cleared in time
3.2 Special Diagnostic Key on Diskettes for Field
Service System Exerciser
The diskette in the maintenance kit must have a special diagnostic code
written on it to allow the system exerciser to write on the diskette when
running in the field service mode. Without this special key, such as
on normal customer diskettes, the system exerciser does not perform
write testing on the diskette. This safety feature prevents accidentally
destroying the customer’s programmed diskettes.
TEST 74 creates a special key on the diskette. The diskette in the
maintenance kit must first be formatted using the T 76 command
(described in Section 3). Secondly, the diskette must have the special
diagnostic key written on it before it can be used with the field service
mode system exerciser.
Example 3–3 shows a successful example of creating a special-key
diskette.