Logical Board Definitions

Every board instance results in the creation of one or more logical boards, or {board instance, frame type} associations. Logical boards are defined by the use of “Frame” parameters in the “Link Driver” section for each board instance. In the earlier example, the NE2000 board instance would be used to create two logical boards as follows:

{NE2000 #1, Ethernet_802.3} logical board 1

{NE2000 #1, Ethernet_II} logical board 2

Note that every logical board is assigned a unique logical board number. These assignments are unique across all board instances and are assigned in the order they are encountered during the loading of board drivers. As each board driver loads and creates a board instance, one or more logical boards are created and numbered using the next available logical board number(s).

For example, consider the following situation (admittedly unusual, but illustrative) where a machine has two NE2000 boards and one token-ring board. The NET.CFG would contain sections like the following:

Link Driver NE2000
[hardware settings for NE2000 board #1, as needed]
Frame Ethernet_802.3
Frame Ethernet_II

Link Driver NE2000
[hardware settings for NE2000 board #2, as needed]
Frame Ethernet_SNAP

Link Driver TOKEN
[hardware settings for Token-ring board, as needed]
Frame Token-Ring_SNAP

The first loading of NE2000.COM (the NE2000 adapter driver) would use the first “Link Driver NE2000” section to create “NE2000 board instance #1” and the first two logical boards for the system. The second loading of NE2000.COM would create “NE2000 board instance #2” and one additional logical board. Finally, the loading of TOKEN.COM would create a fourth logical board. In summary, the four logical boards would be numbered as follows:

{NE2000 #1, Ethernet_802.3} logical board 1
{NE2000 #1, Ethernet_II} logical board 2
{NE2000 #2, Ethernet_SNAP} logical board 3
{TOKEN #1, Token-Ring_SNAP} logical board 4

What if no “Frame” parameters are specified? Each driver will select a single default frame type instead. The default Ethernet frame type is Ethernet_802.2”; the default token-ring frame type is “Token-Ring”. Other types of physical networks have their own sets of frame types and appropriate defaults.