[sf-lug] SF-LUG meeting notes for Sunday August 6, 2017

[Daniel Gimpelevich]

On Sun, 2017-08-06 at 20:55 -0700, Bobbie Sellers wrote:
>      Daniel, Aaron, and Tom stayed behind at the Cafe
> Enchante, Daniel helping and the others working at their
> notebook and netbooks.

I didn't really do anything. Aaron was trying to image some USB flash
drives, and the first one was throwing error -110 in dmesg ("Connection
timed out") and disappearing from lsusb when he repeatedly tried to wipe
a previously dd'ed image of a DVD-ROM of something for macOS, with the
old image still there upon reinsertion. He wrote it off as dead, and I
took it with me when I left as he was trying it on the next one. Later,
I tried a few things with it. The command that worked was:
$ dd count=2048 obs=512 of=/dev/sdb if=/dev/zero oflag=sync
I know that obs=512 is the default, but I'm including it here to
emphasize that larger block sizes absolutely do not work, and not using
oflag=sync does not really work. It appears this drive has very slow
writes and cannot queue them. After the above command, I was able to
format the drive just fine, but attempting to queue writes still knocks
it off the bus, so any write attempt needs a wait before doing anything
else. The drive is:
[8455093.688485] usb 1-1.2: new high-speed USB device number 65 using ehci-pci
[8455093.786864] usb 1-1.2: New USB device found, idVendor=6557, idProduct=4200
[8455093.786872] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[8455093.786877] usb 1-1.2: Product: USB DISK 2.0
[8455093.786880] usb 1-1.2: Manufacturer:         
[8455093.786883] usb 1-1.2: SerialNumber: 90006B83E52BB881
[8455093.787339] usb-storage 1-1.2:1.0: USB Mass Storage device detected
[8455093.787891] scsi31 : usb-storage 1-1.2:1.0
[8455094.788121] scsi 31:0:0:0: Direct-Access              USB DISK 2.0     PMAP PQ: 0 ANSI: 6
[8455094.788594] sd 31:0:0:0: Attached scsi generic sg2 type 0
[8455098.448728] sd 31:0:0:0: [sdb] 15130624 512-byte logical blocks: (7.74 GB/7.21 GiB)
[8455098.449422] sd 31:0:0:0: [sdb] Write Protect is off
[8455098.449431] sd 31:0:0:0: [sdb] Mode Sense: 23 00 00 00
[8455098.450036] sd 31:0:0:0: [sdb] No Caching mode page found
[8455098.450040] sd 31:0:0:0: [sdb] Assuming drive cache: write through
[8455098.455356] sd 31:0:0:0: [sdb] No Caching mode page found
[8455098.455363] sd 31:0:0:0: [sdb] Assuming drive cache: write through
[8455098.459013]  sdb: sdb1
[8455098.462425] sd 31:0:0:0: [sdb] No Caching mode page found
[8455098.462432] sd 31:0:0:0: [sdb] Assuming drive cache: write through
[8455098.462438] sd 31:0:0:0: [sdb] Attached SCSI removable disk