The Fixed Disk Diagnostic Floppy is used to test and diagnose faults in the 1108 processor. Most of the tests are executed selectively and interactively by Xerox service personnel when troubleshooting problems with the Input/Output Processor, Memory Control and Storage Cards, the Central Processor, and the rigid disk.
However, you can load and execute these tests automatically by loading the Fixed Disk Diagnostic floppy and performing a 5-boot.
Diagnostics should be run when recovering from hardware errors, as indicated by error codes in the Maintenance Panel (MP). A list of these codes can be found in Section 8.
The Fixed Disk Diagnostic floppy can also be used to set the time on a stand-alone Xerox 1108.
Performing an Alternate-5 Boot begins a series of tests known as ALAG, (Automatic Load and Go). ALAG is initiated by inserting the Fixed Disk Diagnostic Master Disc floppy and performing the alternate  5-boot.  ALAG  cannot  be  initiated  from 
the rigid disk. Total run time is about 4 minutes 15 seconds. 
The sequence of automatic tests run by ALAG :
Pre-boot	5.0 seconds
Boot	46.5 seconds
Memory	1.3 minutes
Utility 	(Real time clock, etc) 2.0 seconds
Disk (index, seek, etc.)	6.5 seconds  (10MB)
14.5 seconds  (29 MB)
37.0 seconds  (43 MB)
Disk fault analysis	1.2 minutes
Disk scavenger	1.0 seconds  (if no problems found, otherwise it can take in excess of 3 hours)
Media scan	27.0 seconds
The 2-boot eliminates many of the tests run by ALAG and enters an interactive mode whereby the operator can select the tests to be run. This is specially useful when scanning the rigid disk for media defects (bad pages).
If errors are found during Disk Scavenger or Media Scan, the tests will run longer than the 4 minutes 15 seconds.
During the Boot Diagnostics, the system attempts to set the time from a time server on a network. If your 1108 is a stand-alone system, this attempt will halt and the Maintenance Panel will flash code number 0322 alternating with 0002. Simply press the Alt B button to bypass 0322 and continue on to 0323. Booting will continue without further interruption, several more patterns will flash on the CRT, the Memory diagnostics will run for about 
one minute (0645 MP code) and the following messages will appear on the display:
(Stand-Alone 1108 Only):
Locating Time Server. . .failed
Please enter local time parameters
Time zone offset from 	(type -8 for PST, for 
Greenwich (-12 -12):	example. See System 
	Tools section for 
	Greenwich offsets)
Minute offset:	(type carriage-return)
Day of DST (0-366):	(carriage-return)
Last day of DST(0-366):	(carriage-return)
The correct date and time are returned, and you're prompted:
Do you wish to change the time
Confirm (Y/N):	(usually N)
System then responds with the following display where n indicates a 10, 29 or 42 megabyte rigid disk.
nnMegabyte Storage Diagnostic Program 5.0
>Fault Analysis
MP Code:1n99
Examining Physical Volume
>Media Scan
>List New Bad Pages
No new pages
Successful completion
The MP reads 1499 for successful completion of the 42 MB Disk configuration, 1799 for the 29 MB, and 1199 for the 10 MB.
You may depress STOP during any test , if your purpose was a Memory diagnostic test or time set and you wish to boot into Lisp.?
Return to the last logout of Lisp from the Fixed Disk Diagnostic Master Disc by typing Boot or by pressing B Reset.
If ALAG fails during Boot, Utility or Disk tests, the MP will alternate between the failing test number and an error code. Xerox service representatives will take appropriate action based on the meaning of these failures.
If ALAG fails during Memory test, the failing test number will remain on the MP while an error log is being built. Once the error log is completed, the MP goes to 0699. If this number appears on the MP, the Memory Diagnostic test has failed and your Xerox representative should be notified.
If your display reports the rigid disk error message "New Pages," make note of the pages and call the Xerox service representative.