One of the major advantages of USB over Serial/Parallel ports is the increase of speed between the device and your computer. Also, USB devices can be chained together so one USB port can be used by many devices. Lastly, USB is considered "hot swappable" - therefore your computer can easily disconnect one device and discover a new one that you have plugged in.
SAS is SCSI, it connects via a serial cable/connector instead of parallel (long and skinny) connector.
Usually, because a serial port doesn't have to deal with the problem of signal skew that can jumble the data on a parallel port and gets worse proportional to distance.
A Parallel bus has a relatively large number of wires bundled together that enable data to be transferred in parallel. This increases the throughput, or rate of data transfer, between the peripheral and the computer. A Serial bus can be defined as a transmission path over which the participants transmit their data serially, sequentially in time, and using a common medium. In the case of serial transmission, only a single communication link for transferring data from any given end to another one. In the case of parallel transmission, we use multiple numbers of parallel links for the simultaneous transmission of all the data bits in the network.
Serial means that each bit in a data packet is sent over one wire, one after the other (in chronological order). This is the opposite of parallel, where many bits are sent at once over several wires.
Serial Data TransmissionParallel Data transmissionAdvantagesDisadvantagesAdvantagesDisadvantagesUsed over long distancesSlower to send dataFaster than serialNot reliable over long distanceReduces requirement of wiringData may arrive at different times
Serial Data TransmissionParallel Data transmissionAdvantagesDisadvantagesAdvantagesDisadvantagesUsed over long distancesSlower to send dataFaster than serialNot reliable over long distanceReduces requirement of wiringData may arrive at different times
A telegraph key.
Serial communication is preferred over parallel communication for long-distance WAN links primarily due to reduced crosstalk and electromagnetic interference. In parallel communication, multiple wires transmit data simultaneously, increasing the risk of signal degradation over long distances. Serial communication, using a single wire or pair, minimizes these issues and simplifies the design and implementation, allowing for higher data rates and longer transmission distances without significant loss of integrity. Additionally, serial connections require fewer physical resources, making them more cost-effective for WAN applications.
Parallel computing is when you do a lot of different things at once, a graphics card is a parallel processor. The main CPU is a serial processor, it does one thing, but does it really fast, then switches to another. Video editing works better on a parallel processor, for you can encode different frames all at the same time, instead of working on one, then moving on to the next.
There is a greater risk of errors with parallel transmission because especially over longer distances, the bits may arrive at the destination at different times and therefore corrupting the data. Because serial transmission sends each bit one at a time, they always are received in order. Speed of transmission is not always the driving priority, if the information cannot be reliably transferred to the destination all the speed in the universe is useless.
big advantage of parallel transmission is the factor of speed. All else being equal, parallel transmission can increase the transfer speed by a factor of n over a serial transmission. But there is also a very significant disadvantage of parallel transmission. And that is the factor of cost. It can be proved from the fact that the parallel transmission requires 'n'
The full form of SATA is Serial Advanced Technology Attachment. It took over from Parallel ATA in 2003 and offers transfer speeds of up to 6.0 Gb/sec.