Document some of the latest changes from David&John.

[unix-history] / RELNOTES.FreeBSD

diff --git a/RELNOTES.FreeBSD b/RELNOTES.FreeBSD
index c08e27e..d3be116 100644 (file)
--- a/RELNOTES.FreeBSD
+++ b/RELNOTES.FreeBSD
@@ -65,8 +65,7 @@ Please see special notes in /usr/src/KNOWNBUGS (filed under bt742a.c) for
 details concerning possible buggy firmware and undocumented switch settings
 that may be necessary for proper operation of your controller.
 
 details concerning possible buggy firmware and undocumented switch settings
 that may be necessary for proper operation of your controller.
 

-DTC 3290 EISA SCSI controller in 1542 emulation mode (as long as
-you have less than 16MB of main memory).
+DTC 3290 EISA SCSI controller in 1542 emulation mode.

 
 Ultra Store 14F and 34F.
 
 
 Ultra Store 14F and 34F.
 


@@ -77,16 +76,16 @@ inteface card) is the only way a CD ROM drive may be currently
 attached to a FreeBSD system; we do not support SoundBlaster CDROM
 interface, or other "mini SCSI" adapters.
 
 attached to a FreeBSD system; we do not support SoundBlaster CDROM
 interface, or other "mini SCSI" adapters.
 

-The limitation some controllers have with >16MB of memory (as noted)
-is due to the fact that the ISA bus only has a DMA address space of 24 bits.
+Some controllers have limitations with the way they deal with >16MB of memory,
+due to the fact that the ISA bus only has a DMA address space of 24 bits.

 If you do your arithmetic, you'll see that this makes it impossible to do
 direct DMA to any address >16MB.  This limitation is even true of some
 EISA controllers (which are normally 32 bit) when they're configured to
 emulate an ISA card, which they then do in *all* respects.  This problem
 is avoided entirely by IDE controllers (which do not use DMA), true EISA
 If you do your arithmetic, you'll see that this makes it impossible to do
 direct DMA to any address >16MB.  This limitation is even true of some
 EISA controllers (which are normally 32 bit) when they're configured to
 emulate an ISA card, which they then do in *all* respects.  This problem
 is avoided entirely by IDE controllers (which do not use DMA), true EISA

-controllers (like the UltraStor or Adaptec 1742A) or VLB (local bus)
-controllers.
-
+controllers (like the UltraStor or Adaptec 1742A) and most VLB (local bus)
+controllers.  In these cases, the system will use "bounce buffers" to
+to talk to the controller, and is generally the default.

 
 
 2.2. Ethernet cards
 
 
 2.2. Ethernet cards


@@ -297,4 +296,4 @@ hope you enjoy this release of FreeBSD!
 
                        The FreeBSD Core Group
 
 
                        The FreeBSD Core Group
 

-$Id: RELNOTES.FreeBSD,v 1.26 1994/03/22 16:43:59 jkh Exp $
+$Id: RELNOTES.FreeBSD,v 1.27 1994/03/24 21:57:38 davidg Exp $