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		T-300 ERROR MESSAGES		9/18/79

FAULT/STATUS IS AN OCTAL NUMBER CONTAINING FAULT CODE,,STATUS WORD.

UNIT/COMMAND IS AN OCTAL NUMBER CONTAINING UNIT NUMBER,,COMMAND CODE.
UNIT NUMBER 3 IS THE T-300; THAT'S THE ONLY UNIT THAT SHOULD APPEAR.

CYL/SURF-SEC IS AN OCTAL NUMBER GIVING THE DISK ADDRESS.
IT LOOKS LIKE CYLINDER,,xxxyyy WHERE xxx IS THE HEAD NUMBER
AND yyy IS THE SECTOR NUMBER.

THE FAULT CODES ARE: (TYPED IN FROM THE 2561 OPERATION AND MAINTENANCE MANUAL)

1	DRIVE NOT SELECTABLE OR NOT READY
2	ILLEGAL HEAD ADDRESS, SECTOR ADDRESS, OR COMMAND
3	TIMEOUT AWAITING "ON CYLINDER"
4	BAD DRIVE STATUS AFTER "ON CYLINDER"
5	TIMEOUT WRITING SECTOR ID
6	FIFO ERROR WHILE FORMATTING
7	TIMEOUT WRITING SECTOR DATA
10	TIMEOUT AWAITING SEEK COMPLETE OR NOT-BUSY
11	HEADS NOT LOADED (DRIVE NOT ON-LINE)
12	TIMEOUT READING SECTOR DATA
13	TIMEOUT LOOKING FOR START OF TRACK (INDEX)
14	UNABLE TO LOCATE SPECIFIED SECTOR
15	(NOT USED)
16	DMA TIMEOUT DURING DATA TRANSFER
17	DMA TIMEOUT DURING ERROR CORRECTION
2000	PARITY ERROR IN COMMAND DESCRIPTOR IN PDP-11 MEMORY
4000	NXM ERROR IN COMMAND DESCRIPTOR IN PDP-11 MEMORY
10000	"CONSISTENCY ERROR" IN COMMAND DESCRIPTOR IN PDP-11 MEMORY
100000	CONTROLLER RESET DUE TO POWER CYCLING OR CONTROLLER IN FUNNY STATE

STATUS WORD BITS:
100000	COMMAND WAS RETRIED (GOT AN ERROR THE FIRST TIME)
40000	UNCORRECTABLE DATA ERROR (ECC HARD)
20000	CORRECTED DATA ERROR
10000	ID ERROR (DATA ERROR IN SECTOR HEADER)
4000	ADDRESS ERROR (HEADER COMPARE ERROR)
2000	WRITE-PROTECT STATUS OF SECTOR (ABORTS WRITE COMMAND)
1000	ALTERNATE-SECTOR STATUS (ABORTS READ, WRITE, AND CHECK)
400	FIFO OVER-RUN, NOT CORRECTED BY 1 RETRY
200	SEEK ERROR FROM DRIVE
100	DRIVE OFF-LINE OR FAULT
40	(NOT USED)
20	DRIVE FAULT (DEVICE CHECK)
10	NXM ON PDP11 MEMORY
4	PARITY ERROR IN PDP11 MEMORY
2	SYSTEM FAULT (SEE FAULT CODE)
1	DRIVE WRITE-LOCKED, WRITE ABORTED

COMMAND CODES ARE:
2	SENSE STATUS OF DRIVE
3	RUN DIAGNOSTICS ON DRIVE
4	RECALIBRATE
5	SEEK
6	WRITE
20	READ
21-30	READ WITH VARIOUS ERROR RECOVERY FEATURES ENABLED.


THE SWITCHES AND LIGHTS ON THE CONTROLLER (INSIDE THE DOOR) SHOULD
NOT BE MESSED WITH.  THE NORMAL STATE IS ALL SWITCHES DOWN AND ONLY
THE LEFT-MOST LIGHT ON (THE LIGHTS FLASH WHEN DISK TRANSFER IS
HAPPENING.)  MESSING WITH THE SWITCHES CAN CLOBBER THE DATA ON THE DISK.