AT User Diagnostics Revision History


	Written: First pass, March 1989 by Western Digital Corp.

	Purpose: Allow quick, easy and thorough AT hard disk controller
		 and hard disk diagnostics.

	Compatability : All Western Digital AT register compatible
			controllers.
        
	Program Name :	EASYDIAG.EXE  (previous versions USERDIAG.EXE)
        

	1) REPORTS CORRECTABLE DATA ERRORS ... Previous versions
           relied on a test of the STATUS register ONLY. USERDIAG
	   also has this limitation. If a correctable data error
	   is encountered, the test terminates and waits for
	   operator input.
        
	2) COMPLETE DOCUMENTATION ............ Details both the
           (U)ser selected advanced test and the (A)utomatic
	   quick test. Error messages are verbosely explained in the
	   (A)utomatic quick test section of the document.
        
	3) COMMAND TIMEOUTS .................. Have been extended
           to almost a minute on a 12Mhz AT (WDM20). This will
	   allow for 33Mhz 80386's with cache and controllers that
	   issue SLOW recals.
        
        4) ID FIELD RETRIES DISABLED AT ALL TIMES.
        
	5) STRAIGHT-LINE DRQ SERVICE .......... READ DRQ loop does not
	   store data (Write/Read Verify loop does, but more efficiently)
	   Complete test consisting of a re(Z)ero, 256 RANDOM seeks,
	   256 RANDOM two-sector reads, and 50 RANDOM data pattern
	   (W)rite / Read Verifies of last track takes approximately
	   30 sec. (CDC WREN II, 10 Mhz AT)

	6) BAD BLOCK ERRORS IGNORED .......... These errors are
	   reported to screen, but testing continues. This is the
	   ONLY error that is tolerated in the (A)utomatic or
	   (U)ser defined test menus.

        IMPROVEMENTS OF EZDIAG.EXE OVER USERDIAG.EXE
        
                EZDIAG                                  USERDIAG
        
        Automatic Quick Test                            N/A
	Dual test menu ... AUTO + SPECIFIC		Specific (A)ll Test
	Bad Block Errors allowed			Terminates test
        Retries Disabled                                Retries enabled
        ECC Correctable Errors reported                 NOT REPORTED
	Straight-line DRQ service loop			Iterative loop
        Exit to DOS from DIAG menu                      N/A
	Default sector count = 1			Default = 256
        Congratulatory message                          "command successful"
	Single keystroke test selection 		Return required


	Please forward any questions or suggestions to the SYSOP of
	this BBS.

        
	Regards,
        
	Mel Butler
        WDC Dallas