Computer Interfaces and Ports: Ethernet

• An interface is a program that allows a user to interact with computers or to controls used in a program to facilitate interaction.
• A GUI (graphical user interface) is one of the best examples of an interface.
• An interface can also be a physical device, port, or connection that interacts with the computer or other hardware device.
• IDE (integrated drive electronics) and SATA (Serial AT Attachment) are disk drive interfaces for computer hard drives.
• ATAPI (AT Attachment Packet Interface) is an early interface for CD-ROM drives.
• Interfaces/Ports include: USB, VGA, HDMI, AUX, Ethernet, SATA, Thunderbolt, FireWire, MIDI.

Ethernet

• An Ethernet port (also called a jack or socket) is an opening on computer network equipment that Ethernet cables plug into.
• Ethernet ports connect wired network hardware in an Ethernet LAN, metropolitan area network (MAN), or wide area network (WAN).
• Most desktop computers include a built-in Ethernet port to connect wired network.
• A computer's built-in Ethernet port is connected to its internal Ethernet network adapter, called an Ethernet card, which is attached to the motherboard.

FireWire

• FireWire is a method of transferring information between digital devices, especially audio and video equipment.
• Apple developed FireWire, also known as IEEE 1394.
• The latest version of FireWire achieves speeds up to 800 Mbps.
• Future versions are expected to jump to 3.2 Gbps with updated cables.
• FireWire features include fast data transfer, the ability to put lots of devices on the bus, ease of use, hot-pluggable ability.
• Other features include provision of power through the cable, plug-and-play performance, low cabling cost, and low implementation cost.

Thunderbolt

• Thunderbolt was introduced in 2011 by Apple.
• Thunderbolt is a type of hardware interface technology used to connect various devices to a PC, exclusively Apple products.
• There have been several different versions.

MIDI

• Musical Instrument Digital Interface (MIDI) is a standard to transmit and store music.
• MIDI was originally designed for digital music synthesizers.
• MIDI does not transmit recorded sounds, but includes musical notes, timings, and pitch information.
• Receiving devices use this information to play music from sound libraries.
• The first MIDI-compatible instruments were released in 1983.

SATA

• Serial ATA is the standard hardware interface for connecting storage and CD/DVD drives to the computer.
• In 2001, most computers for consumers used the SATA interface for hard drives.
• Servers and high-end workstations may use SCSI.
• Solid state drives (SSDs) increasingly employ the NVMe interface instead of SATA.

USB

• A Universal Serial Bus (USB) is a common interface that enables communication between devices and a host controller.
• Host controllers include a personal computer (PC) or smartphone.
• It connects peripheral devices such as digital cameras, mice, keyboards, printers, scanners, media devices, external hard drives, and flash drives.
• USB has replaced a wide range of interfaces like the parallel and serial port.
• It is intended to enhance plug-and-play and allow hot swapping.
• Plug-and-play enables the operating system (OS) to spontaneously configure and discover a new peripheral device without having to restart the computer.
• Hot swapping allows removal and replacement of a new peripheral without rebooting.

USB Types

• Common types of USB Ports include: Type-A, Micro-A, Mini-A, Type-B, Mini-B, Type-C.
• The USB Type-A connectors, or simply Type-A connectors, are one of the most common USB connectors, also called Standard A connectors.
• It is rectangular-shaped and commonly found on one end of nearly every desktop computer, laptop, media player, TV, game console, etc.
• Most laptops or desktop computers have a USB Type-A port.
• Most modern Apple laptops (Macs) do not have USB Type-A ports.
• USB Type B is smaller than Type A and is square-shaped, and relatively less common than Type B.
• USB Type B is found on computer components like printers, scanners, external hard drives, etc.
• USB Type B has become less common since the introduction of smaller connectors like micro and mini USB, and the reversible USB Type C.
• USB Type C is arguably the most popular USB connector and the most recent, introduced in 2014.
• Due to its small size, it easily fits into the smallest peripherals, such as smartphones and Bluetooth speakers.
• USB Type C is a standard for connecting and charging devices, known for its compact size and functionality.
• "Reverse plug orientation" means USB cables can always be plugged in correctly on the first try.

VGA

• Abbreviated VGA, Video Graphics Array is a standard type of connection for video devices such as monitors and projectors.
• It refers to the types of cables, ports, and connectors used to connect monitors to video cards.
• VGA is rapidly being replaced by interfaces like DVI and HDMI.

HDMI

• HDMI stands for High Definition Multimedia Interface and is the most frequently used HD signal for transferring both high definition audio and video over a single cable.
• It is used in the commercial AV sector and connecting devices such as digital TV, DVD player, BluRay player, Xbox, Playstation and AppleTV with the television.
• HDMI is featuring on laptops and PCs and therefore becoming the standard for the corporate and commercial markets.
• These markets include education, presentation, digital signage and retail display to transmit high-quality audio-video signals from device to device.

AUX

• An auxiliary port (AUX) is a type of standard communications port on a device that accommodates audio signals.
• AUX accommodates audio signals for MP3 players, headphones and headsets, microphones, and speakers.
• If speakers, mics, or headsets are plugged into a primary device, with the possible exception of some USB setups, you're typically connecting in through an auxiliary port.

Input/Output Operations

• I/O operations are accomplished through external devices that exchange data between the external environment and the computer.
• Inputs are the signals or data received by the system and outputs are the signals or data sent from it.
• Performing I/O is to perform an input or output operation.
• In computer architecture, the combination of the CPU and main memory to which the CPU can read or write directly is considered the brain of a computer.
• Any transfer of information to or from the CPU/memory combo, for example by reading data from a disk drive, is considered I/O.

Programmed I/O

• Programmed I/O was the simplest type of I/O technique for the exchanges of data or any types of communication between the processor and the external devices.
• With programmed I/O, data is exchanged between the processor and the I/O module.
• The processor executes a program that gives it direct control of the I/O operation, including sensing device status, sending a read or write command, and transferring the data.
• When the processor issues a command to the I/O module, it must wait until the I/O operation is complete.
• If the processor is faster than the I/O module, this is wasteful of processor time.
• The steps of programmed I/O include the processor executing a program encountering an instruction relating to I/O operation, and that instruction being executed by issuing a command to the I/O module.
• The I/O module performs the requested action based on the I/O command issued by the processor (READ/WRITE) and sets the appropriate bits in the I/O status register.
• The processor periodically checks the status of the I/O module until it finds that the operation is complete.
• Advantages of programmed I/O include it being simple to implement and very little hardware support needed.
• Disadvantages include busy waiting and tying up CPU for long period with no useful work

Interrupt Driven I/O

• A device driver initiates an I/O request on behalf of a process.
• The device driver signals the I/O controller for the proper device, which initiates the requested I/O.
• The device signals the I/O controller that it is ready to retrieve input, the output is complete, or that an error has been generated.
• The CPU receives the interrupt signal on the interrupt-request line and transfers control over the interrupt handler routine.
• The interrupt handler determines the cause of the interrupt, performs the necessary processing and executes a "return from" interrupt instruction.
• The CPU returns to the execution state prior to the interrupt being signaled.
• The CPU continues processing until the cycle begins again.

Direct Memory Access

• When the processor wishes to read or send a block of data, it issues a command to the DMA module including read or write command, sending through read and write control lines.
• The processor sends the number of words to be read or written, communicated on the data lines and stored in the data count register.
• The processor sends the starting location in memory to read from or write to, communicated on data lines and stored in the address register.
• The processor also sends the address of the I/O device involved, communicated on the data lines.