By RSHTECH | 30 October 2020 | 0 Comments
Common Problems in the Use of USAP
What is USAP?
UASP (USB Attached SCSI Protocol) is a new transmission protocol. Mainly to improve the performance of data transmission between USB storage devices such as hard disk drives (HDD), solid-state drives (SSD), and thumb drives.
USB performance will be poor when data capacity and fragmented transmission. The lead lines in the situation caused by the limitations of transmission technology.
*USB uses half-duplex transfer mode and BOT (Bulk-Only Transfer) transfer protocol. The data transmission direction only has a one-way transmission function.
*When USB is upgraded to USB 3.0, the data acceleration mode is upgraded from the previous half-duplex mode to full-duplex mode. Data can be transmitted in two directions (A→B and B→A) simultaneously. Although the bandwidth has been increased by ten times, its architecture is still under BOT.
* Limitations of BOT: Since it has no local location, commands are sent in order, which causes the computer to wait for each read or write operation to complete before issuing another command. The time from the completion of the command to receiving the next command can be longer than the actual command
UASP (USB Attached SCSI Protocol) can solve the above limitations of data transmission.
Since "commands" no longer need to wait in a single stack, UASP devices can be closer to the theoretical maximum coefficient of the USB bus. UASP will command, status, input, and output multiple separate I/0 "pipes", thereby eliminating the old BOT "command, wait, response, 1/O, wait for status response" cycle. There is no need to wait for the completion of the previous data transfer before transferring data.
When the device can no longer accept commands, it will return a full queue on the status pipe.
UASP was introduced as part of the USB 3.0 standard, but the premise is to use compatible hardware, firmware, and drivers, and it can also be used with devices that comply with the slow USB 2.0 standard.
Here below is the checklist:
1. The USB controller on your computer needs to support UASP.
2. Your USB 3.0 device supports UASP.
3. Your computer has installed the correct driver.
How do I know if the computer supports UASP?
To use a device that supports UASP, you will need to be running Windows 8 or higher, or Mac OS X 10.8 or higher. Certain versions of Linux running kernel 2.6.3 and higher can take advantage of UASP, but it is limited to only a small number of supported hardware.
All of the RSHTECH SATA hard drive enclosures and docking stations support UASP. In addition to converting your idle hard drive into a portable hard drive, you can also experience the performance improvement brought by UASP technology.
Windows
1.Press Win + X keys together on the keyboard and click Device Manager.
2.Expand the "Storage Controllers" node and see if it has a "USB Attached SCSI (UAS) Mass Storage Device" listed.
3.If not, then expand the "Universal Serial Bus controllers" tree node in Device Manager.
4.Double click on the "USB Mass Storage Device" for which you wish to check this.
5.Go to the Driver tab and click the Driver Details button.
6.If it says USBSTOR.sys, then it means Windows is using the older Bulk-Only Transport Protocol with your USB device. If it says UASPStor.sys, then it means UAS Protocol is in use.
Mac OS
To check whether your MacBook supports UASP, please go to About This Mac>System Report.
If you can find "I0USBAttachedSCSl" on "Software"> "Extensions", your MacBook supports the UASP protocol.
Linux
To check if Linux is using UASP or BOT, run Isusb -t and look for "driver = uas" instead of "driver = usb-storage"
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