Special considerations concerning hardware conflicts

Hardware conflicts may arise when certain equipment is used together. See:

• ``Mixing 16-bit with 8-bit ISA networking adapters''

• ``Interrupt 2 inconsistencies on ISA computers''

• ``Graphics and network adapter conflicts''

Mixing 16-bit with 8-bit ISA networking adapters

Mixing 16-bit adapters with 8-bit adapters poses special problems on ISA machines. ISA machines reserve the RAM address regions between 640KB and 1MB for devices such as video adapters. This memory area is divided into these 128K regions:

0xA0000 - 0xBFFFF
0xC0000 - 0xDFFFF
0xE0000 - 0xFFFFF

The first region is usually occupied by the video adapter. In the remaining two regions, you must not use 16-bit adapters with 8-bit adapters (or with 16-bit adapters operating in 8-bit mode). You can use a 16-bit adapter with an 8-bit adapter if they are configured to use different memory regions. For example, if you have a 16-bit network adapter configured using the memory region D0000 through D4000, you should not configure any 8-bit adapter to use addresses in the range C0000 through DFFFF.

Interrupt 2 inconsistencies on ISA computers

Interrupt vectors on IRQ2 are sometimes lost because of inconsistencies in some ISA computers. If you have verified that your system is correctly installed, but you are losing interrupts on IRQ2, it is probably due to a hardware defect. To work around this problem:

• Choose another available interrupt vector.

• Reconfigure your software using the Network Configuration Manager.

• Reconfigure your hardware by changing jumper settings or using a setup program, if needed.

Graphics and network adapter conflicts

Many video adapters have ``vertical graphics retrace'', which is associated with IRQ2. If your network board is also configured for IRQ2, this causes a problem when attempting to send or receive data from the network adapter. To work around this, consult the documentation for your video adapter to determine if the ``vertical graphics retrace'' can be disabled. If it cannot, the network board must be configured for another IRQ that does not conflict with any other configured devices on the system. This has been known to occur with the Genoa SVGA and Orchid Prodesigner VGA adapters.

Some video and network adapters might attempt to use the same shared memory segment. This has been known to occur with network adapter using D0000 and the Paradise and Video 7 1024i video adapters, and it might occur with others as well. Changing the memory I/O address on one of the devices or setting the network adapter to use C0000 might help. Refer to your video adapter documentation for more information.