RE: Twinax/ethernet cards and freezing conflicts; was x

[Neil Palmer <npalmer@xxxxxxxxxxx>]

Jerry,

Great tip !    Thanks !


Neil Palmer                                AS/400~~~~~      
NxTrend Technology - Canada   ____________          ___  ~     
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> -----Original Message-----
> From: Jerome Draper [SMTP:jdraper@wco.com]
> Sent: Tuesday, August 25, 1998 3:24 PM
> To:   MIDRANGE-L@midrange.com
> Subject:      Twinax/ethernet cards and freezing conflicts; was x
> 
> At 09:30 AM 8/25/98 -0700, you wrote:
> >At 07:01 PM 8/24/98 -0600, you wrote:
> >>No, it's not guaranteed to cause locks/hangs, but it HAS occured at
> 3 of
> >>our customers in the last 6 months !
> 
> This could be of interest to those facing PC conflicts and mysterious
> freezeups:
> 
> As we all know, there are now PC's beyond the ole 8bit ISA style that
> have
> 16bit and 32bit (PCI) busses.  
> 
> 8bit ISA cards are limited to 8bit data paths and yet decode 10bit i/o
> addresses.  16bit cards decode 16 address bits and 32bit cards decode
> 32
> address bits.  All addresses are visible on the buss of the PC to all
> cards
> no matter whether they are 8bit, 16bit, or 32bit.  Each card decodes
> what
> it needs or is allowed to decode.
> 
> There is an address overlay possibility of that can happen because
> some
> cards can only decode part of the total address.
> 
> For example, an address of 0B03 decoded by a 32bit PCI card would
> conflict
> with address 0303 decoded by an 8bit ISA card.  If you decode the
> first 10
> bits of either address you come up with 303 (the 12th address bit is
> not
> checked by the 8bit cards).
> 
> B03 as binary would be 0000 1011 0000 0011
> 303 as binary would be        11 0000 0011
> 
> If an 8bit card sees the 303 it reponds to that address no matter
> whether
> it's B03 or 303.  
> 
> Conslusion:
> 
> There are cases where changing the I/O address may solve the freezing
> problem even when there is no aparent conflict.
> 
> Regards,
> 
> 
> Jerry
> 
> 
> 
> Jerry Draper, Trilobyte Software Systems, since 1976
> Specializing in connecting PC's, Windows, MAC's, and LAN's to the
> AS/400
> Representing Synapse, Apple, IBM, UDS, Nlynx, MI, DCI, Netsoft, etc.
> (415) 457-3431; (415) 258-1658fax; jdraper@wco.com
> 
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