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Item FDPGZ         -PRO                                                         
.SP 2                                                                           
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TITLE: 950118 TIMING HANG ON IBM PC 300 SERIES - 486 SYSTEMS AND ON             
              ALL APTIVA'S FROM THE 310 (2144-22P) THROUGH THE 530              
              (2144-66P).                                                       
                                                                                
DESCRIPTION OF SYMPTOMS:                                                        
 When the IBM PC 300 Series - 486 Systems  BIOS code switched CMOS              
 banks, OS/2 (and the physical clock Device Driver) did not know                
 that the CMOS bank was switched. If an IRQ 8 (realtime clock                   
 interrupt) came in when the CMOS bank was switched, then the system            
 would hang because the clock DD would read the RTC CMOS locations              
 on the 2nd bank when it should have read them on the 1st bank.                 
                                                                                
 The OS/2 virtual DD (VCMOS.SYS) did not allow writes to CMOS with              
 addresses < 0Eh.  So, the Rapid Resume data could not be written by            
 a VDM (DOS session or windows).  VCMOS.SYS virtualizes ports 70H               
 and 71H.                                                                       
                                                                                
RESOLUTION:                                                                     
                                                                                
VCMOS.SYS will now virtualize ports 22H and 24H when on IBM                     
PC 300 Series - 486 Systems  or Aptiva.                                         
A fix must be applied to the OS/2 system to correct this                        
problem.                                                                        
                                                                                
How to apply the fix                                                            
                                                                                
In the fixes sent to you will be a file called VCMOS.SYS.  After the            
install is complete, copy VCMOS.SYS to ?:\OS2\MDOS directory (? is              
the drive you installed OS/2 into).                                             
 NOTE: Please refer to PDDB Item FFZTV title APTIVA UPDATE.                     
       It has information on how to get the fix.