screwy IRQ numbers from win2k rc2

[Chucky Cheese]

i just installed win2k rc2 on my system and everything is running fine, but w2k seems to think it has an endless supply of irqs. this is what it reports:

System Information report written at: 10/17/1999 10:36:52 AM
[IRQs]

IRQ # Device

128 Matrox Graphics G400 AGP

31 Intel 82371AB/EB PCI to USB Universal
Host Controller

48 Symbios Logic 896, 22910 PCI SCSI
Adapter

49 Symbios Logic 896, 22910 PCI SCSI
Adapter

60 Creative SB Live! Basic (WDM)

64 3Com EtherLink XL 10/100 PCI TX NIC
(3C905B-TX)

0 System timer

1 PC/AT Enhanced PS/2 Keyboard)

4 Communications Port (COM1)

6 Standard floppy disk controller

8 System CMOS/real time clock

13 Numeric data processor

12 Microsoft PS/2 Mouse

whatever! anyway any insight is welcome

chucky



[This message has been edited by Chucky Cheese (edited 18 October 1999).]

[noackjr]

Ah... You've struck upon one of the joys of NT based operating systems: You have 256 IRQs. Not an endless supply, but more than you need (and a hell of a lot better than 15). The reason for this is higher level systems needed more IRQs because they had more components. Well, NT solved this by giving you a ton more IRQs. Win98 (and maybe Win95) solved this another way by allowing PCI and AGP devices to share IRQs. This sharing works for PCI 2.1 devices fairly well, but grab an earlier PCI device and you may be stratching your head two weeks later still trying to get it to work. With NT's solution, everybody gets their own IRQ and they are happy.

If anyone else has a better explanation or if I am wrong (it has happened before...) let us know .

Jon

[Chucky Cheese]

jon

after reading your reply i took the number of irqs' in my(or any other x86 computer i guess), that being 16 irqs'(0-15) and multiplied it by 16=256. have they somehow turned the apic into an ARRAY???...which leads to wonder if it's a dual processor thing???

chucky

[noackjr]

Chucky,

16... darn!!! You are right, not 15.

Good thought about it being a multiprocessor thing. However, with a single processor I still get all 256 IRQs. However, I am basing this observation on my system, which had a multiprocessor motherboard even though I was running a single processor. Not sure about the implementation, it could be an array...

Anybody out there actually know for sure about this stuff?

Jon

[Zypher]

I have only rc1 right now, new cds haven't come yet :/ blah

But it has the same list as w98, and sad to say, stops at 0-15 :/

I'd LOVE to have 256 usable...just like I'd love to have a switched 64/66 pci backplane on a octal rackmount 20U.

The duals & quads I work and play with (when no one's looking ) don't get anymore than 16 either...damn WTF crap are all you looking at? Must be too rich for my employer.

[noackjr]

Hmmmm, I'm not sure what to tell you. Anybody know what's going on here? I have heard it is a multiprocessing thing, but I really don't know any more than I have 256 IRQs. Maybe it has to do with multiprocessing architecture? Anyone with a clue please let us know.

Jon

[MarkV]

Hi,

I found this on the MS Knowledge Base. Hope it helps!

<a href="http://support.microsoft.com/support/kb/articles/Q180/2/87.ASP">http://support.microsoft.com/support/kb/articles/Q180/2/87.ASP</a>


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Mark Veneziano