What is the Bus Structure in Computer Organization?

A bus is a group of wires used to communicate between the computer and a microprocessor. Buses combine the internal components of any device. All devices and parts use buses for sending informative signals to each other. In the computer, all members attach to the microprocessor through buses.

How do buses help the computers? Buses allow the device to perform its functions properly. These buses send different instructions, information, and data values to all devices and components inside the computer. After this article, you will learn about computer buses’ functions, importance, types, pros, and cons. You will also learn some unique and interesting facts which make you surprised. 

Main Functions of Computer Buses

Buses play a vital role in connecting devices and microprocessors. Some explanation about the primary functions of computer buses is available here.

Data Sharing

Buses use for data transferring between the computer and processors. The data move in parallel, which allows the exchange of 1,2, four, or even 8 bytes of data at a time. Buses have different groups on the base of how many bits can move at the same time. For example, buses can move in 8-bit, 16-bit, and 64-bits.

Addressing

the buses’ address lines evaluate the data’s destination. The address bus represents the total number of address lines. The total number of address lines decides the width of the address bus. The width of the address bus calculates the memory capacity of the system. The menu of address lines uses for addressing input/output ports. The higher-order bits calculate the bus components, while the lower-order bits determine the input/output terminals.

Power

The buses supply power to different devices connected to them. The computer can perform quickly on the base of the bus’s capacity. It is unsuitable for the disk drive because it requires a different connection to the power supply unit.

Timing

The control lines of the buses show the timing information with the command. There are two methods for taking time information from the control signals. The bus gives a system clock signal to connect the devices attached to it.

Types of Bus Structure

There are three types of computer buses. The role of every bus is quite different from each other. You can learn here about their importance and their primary function.

Address Bus

Address buses operate for address transfer. It is a single-directional bus. The address shift from the CPU to memory and input to output is single-directional. It contains 16, 20, 24, or more parallel signal lines. Nowadays, computers also have bi-directional address buses.

Data Bus

Data buses send data from the CPU to memory and input to the output terminals. It gets data from memory and sends it to the device controller. It can also write data to memory. It is a double-way directional bus with good speed. It consists of 8,16,32, and more parallel signal lines.

Control Bus

The control bus sends control signals to manage control activities. It is double-way directional. The CPU gives control signals to the control bus to empower the outputs of addressed memory devices or dock devices. In control, indications include the following:

1. IOR (Input/Output read)
2. INTR (interrupt request)
3. MEMR ( memory read)
4. MEMW ( memory writing)
5. BG (bus grant)
6. IOW (input/ output write)
7. BR (bus request)
8. RST (reset)
9. RDY (ready)
10. HLDA 
11. HLD ( hold)

Advantages and Disadvantages of Buses in Computer Systems

There are many advantages and disadvantages of buses. Nobody can’t refuse its importance. After all, there are many drawbacks of buses in computer systems. 

Benefits of Buses in Computer Organization

There are many benefits of buses. A computer is only meaningful with buses in the system. Some of the essential benefits of computer buses mention below.

1. Buses combine the inner components of the computer.
2. It helps in data sharing in the whole system.
3. A bus uses a single set of wires to connect with the subsystem.
4. These buses are relatively inexpensive.
5. Buses use two methods for communicating one is I/O instructions, and the second is memory-mapped I/O.
6. You can add a new machine efficiently.
7. Anybody can share a single set of wires in different ways.

Drawbacks of Buses in Computer Organization

There are many advantages and disadvantages of computer buses. Here you can study some drawbacks of computer buses.

1. A large number of connected devices can slow the speed of buses.
2. It takes a lot of work to handle Troubleshooting separate source problems.
3. Bus topology is not beneficial for large networks.
4. Identifying the actual problem in buses is tough when the network goes down.
5. Two terminals are compulsory at the bottom of the main cable.
6. Buses contain communication buttons that create a problem.
7. The cast of double and multiple bus structures is very high.

Main Difference Between Single Bus and Double Bus Structure

There are two different types of computer buses on the base of size. One is a ‘single-bus structure, and the second is a ‘double-bus structure.’ You can study the main difference between them.

Single Bus Structure

1. Only one common bus connects microprocessors and devices in a single-bus structure system.
2. The same memory address space is beneficial for the input and output units.
3. It is a meager cost to have a single bus.
4. In a single bus, the structure will be small because there is a small number of wires.
5. Its performance is prolonged.

Double Bus Structure

1. In a double bus structure, one bus helps get instructions, while the other is useful for obtaining the data required for implementation.
2. Here, Input/output buses connect input/output units.
3. Both (Instructions and data) go in different buses.
4. It is costly compared to a single bus structure.
5. Its performance is high as compared to a single bus structure.

Some Amazing Facts About Computer Buses

1. The word bus dived from the Latin word Omnibus.
2. Modern buses use parallel and serial connections with computers and microprocessors.
3. The multiple bus structure system in the computer performs fast and best work.
4. A single bus structure system is much cheaper than others.
5. The double bus structure system is expensive, but its performance is high than the single bus structure.

Learn More About Bus Structure in Computer Systems

I wrote many articles on computer buses. In those articles, I briefly explained the working method, types, importance, benefits, and drawbacks of a bus structure in a computer system. You can easily access them with a single click. Please click here:

Conclusion

A bus is a group of wires used to communicate between the computer and a microprocessor. Buses combine the internal components of any device. All devices and parts use buses for sending informative signals to each other. In the computer, all members attach to the microprocessor through buses.

There are three types of computer buses. The role of every bus is quite different from each other. You can learn about their importance and their primary function. A computer is only meaningful with a robust bus structure system.

FAQs About Bus Structure in Computer Organization?

I have put all the question related to the computer organization. You can study all question and can also ask further query.