La séance de questions et réponses d’aujourd’hui nous est offerte par SuperUser, une sous-division de Stack Exchange, un groupe de sites Web de questions-réponses dirigé par la communauté.
Photo gracieuseté de itBox24 (Flickr).
La question
Le lecteur superutilisateur IAmJulianAcosta souhaite savoir si deux lecteurs connectés à un concentrateur USB peuvent transférer des données directement via le concentrateur USB et contourner complètement l'ordinateur:
If I connect two USB drives to an external hub and I copy data from one drive to the other, does the data go through the computer or will the USB hub manage the data? Does this have some performance benefit?
Quelle route prendront les données lors de la copie d'un lecteur USB vers un autre?
La réponse
Les contributeurs de SuperUser, Lzam, Luu Vinh Phuc et Fixer 1234 ont la solution pour nous. Tout d'abord, lzam:
No, this will not work. All the data you are copying will need to be read by the computer from the source drive before it is copied to the target drive.
If anything, having two hard-drives connected to the same USB hub might slow things down. If you have multiple devices connected to the hub, they have to share the bandwidth.
Suivi de la réponse de Luu Vinh Phuc:
USB is a host-driven protocol, not a peer-to-peer standard like firewire. Drives are just devices, they are not hosts that control or decide anything. Without the host, they cannot even interact with the outside world.
Assuming that you can connect the two drives like that, how will they know which files and/or folders you want to copy? How will they know which drive to copy from and will they overwrite duplicated files? How will they behave if the drives are full?
Et notre réponse finale de fixer1234:
A USB hub is just a way to share a connection to the computer when you do not have enough USB ports for all the devices you want to connect. Devices connected to the computer through a USB hub never talk to each other. The USB hub ensures that traffic between the computer and the connected devices goes to and from the right device as if each was literally connected to a USB port on the computer.
There is no performance benefit and there may be a performance detriment. The USB hub itself is connected to the computer through a USB connection, so everything connected to the USB hub has to share the bandwidth of that connection. Hard-drives can consume a lot of the USB hub’s bandwidth and affect the performance of other devices attached to the USB hub. You generally do not want to connect hard-drives through a USB hub at all because of that.
Avez-vous quelque chose à ajouter à l'explication? Sound off dans les commentaires. Voulez-vous lire plus de réponses d'autres utilisateurs de Stack Exchange doués en technologie? Découvrez le fil de discussion complet ici.
