Hey Alan!

I should have posted these different usb sata adapters just to make sure everything as it should be. Same machine, same drive, different cables on different usb version interfaces.

usb-a sata adapter:
<Esc>:read !dmesg
[ 8055.515419] usb 9-1: new SuperSpeed USB device number 3 using xhci_hcd
[ 8055.527245] usb 9-1: New USB device found, idVendor=152d, idProduct=0576, bcdDevice=12.14
[ 8055.527249] usb 9-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 8055.527252] usb 9-1: Product: SABRENT
[ 8055.527254] usb 9-1: Manufacturer: SABRENT
[ 8055.527256] usb 9-1: SerialNumber: 0000000000015
[ 8055.528742] scsi host0: uas
[ 8055.529334] scsi 0:0:0:0: Direct-Access SABRENT 1214 PQ: 0 ANSI: 6
[ 8056.232787] sd 0:0:0:0: [sda] 976773168 512-byte logical blocks: (500 GB/466 GiB)
[ 8056.232791] sd 0:0:0:0: [sda] 4096-byte physical blocks
[ 8056.233008] sd 0:0:0:0: [sda] Write Protect is off
[ 8056.233011] sd 0:0:0:0: [sda] Mode Sense: 53 00 00 08
[ 8056.233382] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 8056.257467] sd 0:0:0:0: [sda] Preferred minimum I/O size 4096 bytes
[ 8056.257470] sd 0:0:0:0: [sda] Optimal transfer size 33553920 bytes not a multiple of preferred minimum block size (4096 bytes)
[ 8056.286832] sda: sda1 sda2 sda3 sda4
[ 8056.286968] sd 0:0:0:0: [sda] Attached SCSI disk

usb-c sata adapter:
<Esc>:read !dmesg
[ 933.693549] usb 7-1: new SuperSpeed USB device number 3 using xhci_hcd
[ 933.705366] usb 7-1: New USB device found, idVendor=174c, idProduct=55aa, bcdDevice= 1.00
[ 933.705370] usb 7-1: New USB device strings: Mfr=2, Product=3, SerialNumber=1
[ 933.705373] usb 7-1: Product: Ugreen Storage Device
[ 933.705375] usb 7-1: Manufacturer: Ugreen
[ 933.705378] usb 7-1: SerialNumber: 0219112201A7
[ 933.706581] scsi host0: uas
[ 933.707261] scsi 0:0:0:0: Direct-Access Samsung SSD 870 EVO 500G 0 PQ: 0 ANSI: 6
[ 933.708870] sd 0:0:0:0: [sda] 976773168 512-byte logical blocks: (500 GB/466 GiB)
[ 933.708945] sd 0:0:0:0: [sda] Write Protect is off
[ 933.708949] sd 0:0:0:0: [sda] Mode Sense: 43 00 00 00
[ 933.709056] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 933.732720] sd 0:0:0:0: [sda] Preferred minimum I/O size 512 bytes
[ 933.732723] sd 0:0:0:0: [sda] Optimal transfer size 33553920 bytes
[ 933.753451] sda: sda1 sda2 sda3 sda4
[ 933.753663] sd 0:0:0:0: [sda] Attached SCSI disk

Given that the drive is slower than either interfaces the usb version shouldn't make a difference ... or does it? Looking at the optimal transfer size 33553920 bytes, I would suspect that there isn't a difference but I have to wonder about the "not a multiple of preferred minimum block size (4096 bytes)" on the usb-a adapter makes me a tad wary.

Writing a huge file - perhaps a slackware-current iso? - ought to settle the issue but my hunch is that if there is a difference then the usb-c sata adapter will be the winner. The output itself inspires greater confidence.

Дуже груви,
Maurice

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