SOL White Paper

9. Role of BIOS in SOL
During POST, BIOS quarries the BMC for the SOL status. If SOL is found active then BIOS
forces the console on SOL serial port. BIOS also auto enables redirection of DOS, Linux* shell,
Windows* SAC on to the serial port. BMC acts as a bridge between serial data coming from
SOL port and the network proxy. BMC picks up the data on serial port and converts them into
RMCP+ LAN packets so that the SOL proxy can decode the packets and display the serial data
on remote telnet console.
Often the BIOS Console redirection and SOL are considered as same features of BIOS. But the
truth is, they are two independent features of BIOS. SOL uses the services of Console
redirection subsystem to redirect the console over SOL serial port. Depending upon current
configuration of BIOS console redirection setting, there are three cases,
9.1 Case 1: Console Redirection disabled and SOL Active
BIOS quarries SOL status during POST. If SOL active then BIOS will force the Console on SOL
serial port, even though console redirection is disabled in BIOS setup. During this process,
BIOS Setup will not reflect console redirection settings because, on next boot of SOL is not
active then we will be enabling console on SOL serial port forever.
9.2 Case 2: Console Redirection enabled on SOL serial port and SOL Active
BIOS quarries SOL status during POST. If SOL active, then BIOS will over ride console
redirection Baud rate settings with that of SOL Baud settings. For examples, assume SOL is
configured at 57600 baud where as console redirection has 115200 Baud. Then BIOS will
enable console on SOL port with 57600 Baud, however BIOS will not change this in BIOS
Setup due to reason mentioned in Case 1.
9.3 Case 3: Console Redirection enabled on system Serial (non SOL) port and SOL active
BIOS quarries SOL status during POST. If SOL active, then BIOS will enable Console on SOL
serial port. BIOS will also enable console on non SOL serial port. Hence you will see console
on both SOL console and non SOL serial port.
Page 15 5/26/2010