Subject: Re: 4GB Quantum SCSI hard disk
To: pfwong <>
From: Rick Byers <>
List: netbsd-users
Date: 12/05/1997 14:00:44
The "DMA beyond end of ISA" messages are caused by a limitation of the ISA
bus - only 24 address lines.  This means that ISA cards can't address
memory above 16 Mb.  There are several ways around this:

-Get a PCI SCSI card (assuming you have PCI slots) - this is better for
performance anyway.

-Take 16Mb of memory out (I've seen exactly 16Mb of memory still cause
some problems on some motherboard that relocate memory). 

-Get NetBSD 1.3 (when it's released - RSN).  I believe NetBSD 1.3 now has
"bounce buffers" which will fix the problem (someone correct me if I'm

Hope this helps,

On Fri, 5 Dec 1997, pfwong wrote:

> I am new to NetBSD and this user group.   
> I am trying to install NetBSD 1.2.1 into a pentium PC with 32MB RAM and
> a 4GB SCSI hard disk. However I got the following error message when it
> was trying to create the partitions:
> Labeling disk sd0...aha0: DMA beyond end of ISA
> aha0: DMA beyond end of ISA
> sd0: could not mode sense (4/5); using ficitious geometry
> aha0: DMA beyond end of ISA
> sd0(aha0:0:0): could not get size
> sd0: no disk label
> aha0: DMA beyond end of ISA
> Configuration of the PC
> ISA Adaptec 1542CF SCSI controller with switch 1 (termination) and 5
> (disable floppy) to ON and all others are OFF. The I/O port 330 and BIOS
> address DC000. IRQ is 11 and DMA is 5.
> SCSI disk is Quantum Fireball ST 4.3GB 
> 2 PCI 3COM 3C905 (Etherlink XL PCI) with IRQ set to 9 and 10.
> Could anyone tell me how I can get around this problem? Any help is much
> appreciated.
> Thanks in advance.
> **********************************************************************
> Pui Wong
> 					Tel: 905-479-8090
> GN Nettest (Canada) Inc			Fax: 905-475-6524
> **********************************************************************

Rick Byers                                      Internet Access Worldwide                                		     System Admin
University of Waterloo, Computer Science                    (905)714-1400