Original from  Coridon Henshaw  to Lawrence Garvin on 04-25-1998
Original Subject: Adsl,Dhcp &Ddns
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  LG> Nevertheless, based on what you've pointed out, which I cannot find 
fault
  LG> with, I would then modify my earlier statements to recommend moving 
sound
  LG> cards from IRQ10 to IRQ5, and leaving the NIC on IRQ10 -- would you
  LG> agree?
 
CH> Generally yes.
CH> 
CH> However, since the interrupt controllers are programmable, I can't say 
or
CH> sure that the default interrupt priorities are what OS/2 uses.
CH> 
CH> Dennis Tonn?  Does OS/2 reprogram the PICs' priority settings?
 You can't really change the PIC's priorities, they are determined by 
the hardware wiring connected to the PIC(s). What you can do (and 
every OS I have seen does it) is change the "Interrupt number" that a 
line will generate when it hits the CPU. EG: Under Dos, the line 
connected to to IRQ 0 on the PIC comes in as Interrupt 8 in the CPU
side handling. 
 Don't confuse hardware IRQ wiring with generated Interrupt numbers. 
 Yes, OS/2 does change this Interrupt "numbering", it has to since 
protect mode operation "needs" the CPU Interrupt numbers (machine
exceptions) used under real mode for hardware attachment (0 thru 1F). 
 The PIC has been reprogrammed under OS/2 to reflect these lines as 
Interrupt 50 thru 57 (PIC0) and 70 thru 77 (PIC1). 
   Denis       
 All opinions are my very own, IBM has no claim upon them
. 
. 
.
 
 
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