Bus switching structure and computer

A bus switching structure comprising:

• a first and a second bus for transferring a signal;
• a first slot which is connected to the first bus;
• a second slot which is connected to the second bus;
• a third slot which is connected to the first and second I/O busses via switches;
• and
• a bus switching control circuit for controlling the switches to electrically connect the third slot to one of the first and second busses.

A computer comprising:

• a CPU;
• a processor bus which is connected to the CPU;
• first and second bridge circuits for transferring a signal between the processor bus and other busses;
• an I/O bus which is connected to the first and the second bridge circuits, said I/O bus comprises:
• first and second switches,
• a first slot disposed between the first bridge circuit and the first switch,
• a second slot disposed between the first and second switches, and
• a third slot disposed between the second switch and the second bridge circuit;
• and
• a switch control circuit for controlling the first and second switches such that said second switch operates inverse to said the first switch.

A bus switching structure comprising:

• a bus for connecting first and second bridge circuits, said bus comprises:
• first and second switches,
• a first slot disposed between the first bridge circuit and the first switch,
• a second slot disposed between the first and second switches, and
• a third slot disposed between the second switch and the second bridge circuit;
• and
• a switch control circuit for controlling said first and second switches such that said second switch operates inverse to said first switch.

A computer comprising:

• a CPU;
• a processor bus;
• first and second bridge circuits coupled to said processor bus;
• a first I/O bus which is connected to said first bridge circuit;
• a second I/O bus which is connected to said second bridge circuit;
• a first slot which is connected to said first I/O bus;
• a second slot which is connected to said second I/O bus;
• and
• a third slot which is connected to one of said first and second busses alternatively.