H132523 - SYSTEM BOOT/HANG FAILURES W/IBM (ADAPTEC) PCI SCSI-2                 
                                                                                
 SYMPTOM:                                                                       
 There are two basic failure symptoms which may occur as a result               
 of incorrect setting of the "Reverse scan" option on the IBM                   
 (Adeptec) PCI 2940W SCSI Adapter.                                              
                                                                                
 1. The operating system may fail to boot.                                      
                                                                                
    This occurs when either:                                                    
                                                                                
    A.  An adapter that did not have the reverse scanning                       
        option enabled is replaced with a FRU or option adapter                 
        that has the reverse scanning option enabled.                           
                                                                                
    B.  When the reverse scanning option is enabled after the                   
        operating system has been installed to a disk while the                 
        reverse scanning option was disabled.                                   
                                                                                
    C.  If the operating system is installed while the reverse                  
        scanning option is enabled, then the reverse scanning                   
        option is disabled at a later time.                                     
                                                                                
 2. System hangs during or after system boot.                                   
                                                                                
    This may occur because some operating system device drivers                 
    do not support the reverse scanning option.  Even if the                    
    system boots with the reverse scanning option enabled, there                
    may be problems accessing disks once the operating system is                
    fully booted, or during the boot process.                                   
                                                                                
    This could also make it appear as if files or directories                   
    have been corrupted on some or all of the attached disks.                   
                                                                                
 PROBLEM ISOLATION AIDS:                                                        
 The SCSI adapter installed is the IBM (ADAPTEC AHA-2940W) PCI                  
 SCSI-2 F/W Adapter, FRU P/N06H8574.                                            
                                                                                
 FIX:                                                                           
 IBM systems do not support the reverse scan option that is on                  
 the Adaptec AHA-2940W PCI SCSI-2 adapter.                                      
                                                                                
 When installing a system with an Adaptec 2940W card from IBM,                  
 follow the instructions as directed in the User's Handbook                     
 (Server 320, page 122) titled "Using the SCSISelect Utility                    
 Program" to check the for proper configuration, as follows:                    
                                                                                
 1. Start the Server.                                                           
                                                                                
 2. The SCSISelect prompt appears after the "IBM PC Server"                     
    screen appears briefly and then disappears.                                 
                                                                                
 3. Press Ctrl+A immediately after the SCSISelect prompt appears.               
                                                                                
 4. At the first screen select "Configure/View Host Adapter                     
    Setting".                                                                   
                                                                                
 5. Under "Additional Options" choose "Advanced Configuration                   
    Options".                                                                   
                                                                                
 6. Under "Advanced Configuration Options" Ensure that "Reverse                 
    Scan", "IBM Int13 Extensions", and "Boot from CD-ROM" are                   
    all disabled.  (None of these should be enabled unless you                  
    know exactly what you are doing.)                                           
                                                                                
 7. Before saving and exiting "SCSISelect," you might want to                   
    check "SCSI Device Configuration" under "Additional Options"                
    (on the screen that showed "Advanced Configuration Options).                
    On this screen check to make sure that hard disk devices that               
    are installed on the SCSI bus show the proper settings such                 
    as "Send Start Unit Command" YES.                                           
                                                                                
   The AHA-2940/2940W User's Guide discusses the options on this                
   and other screens.                                                           
                                                                                
   Feb. 6, 1996