184:
25:
358:→ Software → Extensions as IOUSBAttachedSCSI (or IOUSBMassStorageUASDriver, depending on the version of OS X) "Loaded: Yes". Drives listed with "Loaded: No" are defaulting to the older, slower Bulk Only Transport (BOT) mode. This may occur if the drive's USB controller, the Mac's USB port, or any attached USB hub doesn't support UASP mode.
239:
interface is 6.0 Gbit/s. When using a USB 3.0 link (5.0 Gbit/s), which is slower than a SATA3 link, the performance will be limited by the USB link. However, USB has continued to improve its transfer rates, with USB4 reaching 80 Gbit/s. Many UAS drives are implemented using a SATA 3
171:
standard, but can also be used with devices complying with the slower USB 2.0 standard, assuming use of compatible hardware, firmware and drivers. UAS was developed to address the shortcomings of the original USB Mass
Storage Bulk-Only Transport protocol, i.e., an inability to perform command
243:
The UAS standard (ANSI INCITS 471-2010 and ISO/IEC 14776-251:2014) has been superseded so it should be referred to as UAS-1. A UAS-2 project was started by T10 but cancelled. That effort was resurrected as UAS-3 which is now a published standard (INCITS 572-2021). Apart from being based on later
244:
versions of other SCSI standards (e.g. SAM-6 and SPC-6 (both under development)) the technical author described the changes between UAS-1 and UAS-3 as follows: "allow the device to switch data transfers from one command to another before the current command is complete".
208:
UAS is defined across two standards, the T10 "USB Attached SCSI" (T10/2095-D) referred to as the "UAS" specification, and the USB "Universal Serial Bus Mass
Storage Class - USB Attached SCSI Protocol (UASP)" specification. The T10 technical committee of the
210:
343:. Drives supporting UAS load Uaspstor.sys instead of the older Usbstor.sys. Windows 8 supports UAS by default over USB 2.0 as well. UAS drivers and products are certified by Microsoft using the
280:
Hubs, the USB part of which was co-developed by AMD and
Renesas. In October 2011, ASMedia USB controllers chips had gained driver support as well (they had support on the hardware side before).
982:
276:
A comparative performance review by VR-Zone in August 2011, concluded that only the NEC/Renesas chips had UAS working drivers. The same
Renesas UAS driver (for Windows) also works with AMD's
240:
drive attached through a SATA to UAS bridge, which limits the a UAS drive to the native SATA transfer rate, however a native USB UAS SSD can take full advantage of higher USB transfer rates.
291:
motherboards support USB3 UASP. A license is required to implement UASP, and not all motherboard manufacturers are prepared to pass on the extra cost of this license to the end user."
970:
228:
UAS drivers generally provide faster transfers when compared to the older USB Mass
Storage Bulk-Only Transport (BOT) protocol drivers. Although UAS was added in the
995:
659:
743:
328:
Silicon Motion's SM232x family of USB Flash Drive (UFD) controllers offers full USB 3.2 UAS performance, reaching data transfer speeds of up to 2 Gbyte/s.
373:(from v11.xx onwards) have reported issues with some misbehaving hardware. The kernel has a built-in blacklist for devices with "quirks" defined in
287:(PCH), an article in MyCE notes: "The native Intel USB3 UASP solution is only supported under Windows 8. To further complicate matters, not all
235:
When used with an SSD, UAS is considerably faster than BOT for random reads and writes given the same USB transfer rate. The speed of a native
594:
177:
956:
975:
638:
344:
42:
108:
786:
1168:
551:
89:
1286:
1178:
508:"USB Attached SCSI (UAS): Enabling Even Better USB 3.0 Performance - Faster USB 3.0 Performance: Examining UASP And Turbo Mode"
61:
485:
46:
573:
1139:
1023:
841:
391:
218:
161:
68:
529:
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355:
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queueing or out-of-order command completions. To support these features, the Bulk
Streaming Protocol was added to the
183:
75:
35:
325:
Fujitsu lists some higher-end chips like the MB86C311A that do support UAS. ASMedia 1053-s and 1153 support UAS.
898:
1204:
428:
722:
57:
925:
437:
USB 3.0 SuperSpeed – host controller (xHCI) hardware support, no software overhead for out-of-order commands
284:
1173:
1044:
943:
460:
403:
Designed to directly address the failings of the USB mass-storage device class bulk-only transports (BOT)
222:
214:
819:
806:
673:
1245:
365:
has supported UAS since 8 June 2014 when the version 3.15 was released. However, some distributions of
295:
262:
862:
507:
445:
Streams were added to the USB 3.0 SuperSpeed protocol for supporting UAS out-of-order completions
82:
1230:
1225:
1161:
1016:
876:
765:
653:
311:
149:
137:
417:
315:
744:"Silicon Motion Launches World's Fastest Single Chip Controller For External Portable SSDs"
1144:
1235:
1281:
1270:
1194:
1149:
1121:
983:
USB Mass
Storage Class Specification for UASP Bootability v1.0 and Adopters Agreement
390:
On older operating systems that do not support UAS class, a UAS device may be run in
1276:
1072:
1065:
1058:
1051:
1009:
362:
258:
176:
specification, and
Streams support was added to the USB host controller interface (
160:
command set. Use of UAS generally provides faster transfers compared to the older
406:
Enables command queuing and out-of-order completions for USB mass-storage devices
153:
24:
232:
standard, it can also be used at USB 2.0 speeds, assuming compatible hardware.
1250:
1209:
842:"Fortysomething Geek: OSX Mountain Lion 10.8 UAS UASP USB Attach SCSI drivers"
377:. Temporary additional quirks can be added via procfs or kernel command line (
145:
16:
Computer protocol for running the SCSI command set over USB for storage drives
530:"What's the Difference Between USB UASP And BOT | Embedded content from"
351:
340:
336:
989:
1240:
1106:
1101:
1096:
1091:
926:"The kernel's command-line parameters — The Linux Kernel documentation"
384:
319:
318:
VL700 controllers all support UASP, while as far as we could find, the
307:
270:
229:
221:(MSC) Working Group develops and maintains the UASP specification; the
168:
1255:
1199:
903:
370:
236:
574:"USB 3.0 Speed Tests: 7-Way Host Controllers Roundup - Page 1 of 11"
448:
USB 3.0 host controller (xHCI) provides hardware support for streams
957:
New API allows apps to send "TRIM and Unmap" hints to storage media
1111:
697:
366:
182:
1116:
410:
277:
173:
157:
1005:
820:"USB 2.0 & 3.0 SCSI Compliance test for UAS on EHCI (LOGO)"
639:"Asus launches USB 3.0 speed booster, UASP support for ASMedia"
322:
ASM1051 and ASM1051E as well as the
Fujitsu MB86C30A doesn't."
1131:
1032:
863:"Phoronix: USB Attached SCSI (UAS) Is Now Working Under Linux"
440:
USB 2.0 High-speed – enables command queuing in USB 2.0 drives
288:
266:
196:
192:
188:
141:
18:
976:
USB Attached SCSI Protocol (UASP) v1.0 and
Adopters Agreement
211:
International Committee for Information Technology Standards
552:"Gigabyte's UASP USB 3.0 Driver Boosts USB 2.0 Performance"
434:
USB 3.0 SuperSpeed and USB 2.0 High-Speed versions defined
213:(INCITS) develops and maintains the UAS specification; the
265:
had introduced working UAS drivers for their boards using
156:. UAS depends on the USB protocol, and uses the standard
486:"Gigabyte adds UASP support to its USB 3.0 motherboards"
306:
Of USB/SATA bridges, "the LucidPort USB300 and USB302,
1001:
807:
USB Attached SCSI (UAS) Best Practices for Windows 8
1218:
1187:
1130:
1084:
378:
374:
49:. Unsourced material may be challenged and removed.
637:TeamVR on October 14, 2011 1:23 am (2014-01-10).
298:SoCs feature UAS support over USB 2.0 in Linux.
723:"USB 3.0-SATA Bridge ICs : Fujitsu Global"
617:"AMD's A75 and A70M FCH gains USB-IF approval"
420:(UNMAP in SCSI terminology) operation for SSDs
225:, Inc. (USB-IF) promotes the UASP technology.
1017:
8:
766:"New USB 3.0 Support Built-In to Windows 8"
658:: CS1 maint: numeric names: authors list (
354:Mountain Lion; drives using UAS show up in
1024:
1010:
1002:
217:(SCSITA) promotes the UAS technology. The
479:
477:
475:
257:A brief hardware roundup in July 2010 by
109:Learn how and when to remove this message
944:"Is FreeBSD-current XHCI 1.1 compliant?"
787:"USB in Windows - FAQ (Windows Drivers)"
692:
690:
387:does not support UAS as of August 2018.
597:. Electronics Eetimes. 4 September 2011
471:
651:
350:Apple added native support for UAS to
199:3.0 adapter and connected to computer.
7:
392:USB Mass Storage Bulk-Only Transport
178:Extensible Host Controller Interface
162:USB Mass Storage Bulk-Only Transport
47:adding citations to reliable sources
595:"USB to SATA3 bridge supports UASP"
345:Windows Hardware Certification Kit
167:UAS was introduced as part of the
14:
996:USB Attached SCSI Protocol (UASP)
844:. Fortysomethinggeek.blogspot.com
840:fortysomethinggeek (2013-04-03).
615:Lars-Göran Nilsson (2011-03-23).
550:Lars-Göran Nilsson (2010-08-11).
484:Lars-Göran Nilsson (2010-07-30).
409:Eliminates software overhead for
946:. lists.freebsd.org. 2018-08-28.
879:. bugs.launchpad.net. 2011-10-05
822:. Msdn.microsoft.com. 2013-07-26
789:. Msdn.microsoft.com. 2013-11-16
425:Up to 64K commands may be queued
339:added native support for UAS to
23:
899:"torvalds/linux: unusual_uas.h"
897:Torvalds, Linus (28 May 2023).
34:needs additional citations for
278:A70M and A75 Fusion Controller
140:used to move data to and from
1:
971:USB Attached SCSI - 3 (UAS-3)
528:Sandler, Steve (2012-03-18).
219:USB mass-storage device class
764:Jerome Myers (2012-10-25).
1303:
572:TeamVR (August 23, 2011).
191:(2242) solid-state-drive (
130:USB Attached SCSI Protocol
1039:
1205:USB flash drive security
674:"Beyond USB3, with UASP"
506:Andrew Ku (2012-06-19).
429:SCSI Architectural Model
394:mode for compatibility.
332:Operating system support
283:As for support by Intel
144:storage devices such as
990:USB Attached SCSI (UAS)
877:"UAS Ubuntu Bug-Report"
285:Platform Controller Hub
1287:Computer storage buses
1045:USB Implementers Forum
746:. ir.siliconmotion.com
461:SCSI / ATA Translation
223:USB Implementers Forum
215:SCSI Trade Association
200:
186:
296:Allwinner Technology
43:improve this article
532:. Electronic Design
263:Gigabyte Technology
58:"USB Attached SCSI"
510:. Tomshardware.com
379:usb-storage.quirks
356:System Information
253:USB controller/hub
201:
150:solid-state drives
1264:
1263:
1231:Ethernet over USB
1226:Enhanced mini-USB
992:(data on t10.org)
431:(SAM-4) compliant
314:TUSB9261 and the
312:Texas Instruments
195:) connected into
138:computer protocol
122:USB Attached SCSI
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302:Storage devices
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164:(BOT) drivers.
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1246:Serial adapter
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965:External links
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960:
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935:
930:www.kernel.org
917:
889:
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854:
832:
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778:
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629:
619:. SemiAccurate
607:
586:
564:
554:. SemiAccurate
542:
520:
498:
488:. SemiAccurate
470:
468:
465:
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463:
456:
453:
452:
451:
450:
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443:
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438:
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413:command phases
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1195:Juice jacking
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1122:USB On-The-Go
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736:
725:. Fujitsu.com
724:
718:
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669:
666:
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655:
641:. Vr-zone.com
640:
633:
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611:
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596:
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576:. Vr-zone.com
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375:unusual_uas.h
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99:December 2013
91:
88:
84:
81:
77:
74:
70:
67:
63:
60: –
59:
55:
54:Find sources:
48:
44:
38:
37:
32:This article
30:
26:
21:
20:
1156:
1140:Mass storage
986:, 2013-03-04
978:, 2009-06-24
952:
938:
929:
920:
908:. Retrieved
902:
892:
881:. Retrieved
871:
857:
846:. Retrieved
835:
824:. Retrieved
814:
802:
791:. Retrieved
781:
770:. Retrieved
759:
748:. Retrieved
738:
727:. Retrieved
717:
705:. Retrieved
701:
678:. Retrieved
668:
643:. Retrieved
632:
621:. Retrieved
610:
599:. Retrieved
589:
578:. Retrieved
567:
556:. Retrieved
545:
534:. Retrieved
523:
512:. Retrieved
501:
490:. Retrieved
389:
383:
363:Linux kernel
360:
349:
335:
327:
324:
305:
293:
282:
275:
259:SemiAccurate
256:
242:
234:
227:
207:
169:USB 3.0
166:
154:thumb drives
152:(SSDs), and
133:
129:
125:
121:
120:
105:
96:
86:
79:
72:
65:
53:
41:Please help
36:verification
33:
1145:Flash drive
261:found that
146:hard drives
1271:Categories
1251:PoweredUSB
1236:Decoration
1210:USB killer
1059:connectors
883:2019-08-17
848:2014-01-20
826:2014-01-20
793:2014-01-20
772:2014-01-20
768:. Plugable
750:2023-08-28
729:2014-01-20
680:2014-01-20
676:. Myce.com
645:2014-01-20
623:2014-01-20
601:2014-01-20
580:2014-01-19
558:2014-01-19
536:2014-01-20
514:2014-01-19
492:2014-01-19
467:References
69:newspapers
1150:FlashCard
698:"USB/UAS"
352:OS X 10.8
341:Windows 8
337:Microsoft
1188:Security
1085:Versions
1052:Hardware
809:, page 6
654:cite web
455:See also
416:Enables
369:such as
310:SW6315,
204:Overview
148:(HDDs),
1066:cabling
385:FreeBSD
320:ASMedia
308:Symwave
273:chips.
271:Renesas
230:USB 3.0
136:) is a
83:scholar
1256:WebUSB
1200:BadUSB
910:28 May
904:GitHub
707:30 May
371:Ubuntu
294:A few
237:SATA 3
85:
78:
71:
64:
56:
1219:Other
1174:Video
1112:USB-C
1073:power
998:(PDF)
398:Goals
367:Linux
128:) or
90:JSTOR
76:books
1282:SCSI
1157:UASP
1117:USB4
912:2023
709:2023
660:link
418:TRIM
411:SCSI
361:The
174:USB3
158:SCSI
134:UASP
62:news
1277:USB
1241:Hub
1162:SSD
1107:3.0
1102:2.0
1097:1.1
1092:1.0
1033:USB
381:).
316:VLI
289:Z77
267:NEC
197:USB
193:SSD
189:M.2
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