On Mon, September 8, 2014 21:25, Alan Stern wrote: > On Mon, 8 Sep 2014, Mark wrote: > >> ... >> I managed to find an old Jaz drive and tested it with my cable. It seems >> to work fine, so the cable firmware does restrict itself to working with >> Jaz drives. I had the drive SCSI ID set to 4, so it seems the firmware >> scans the bus and talks to the first(?) Jaz drive it sees. >> >> However there were still four messages saying "usb 7-1: reset full speed >> USB device number 2 using uhci_hcd" in dmesg output. But the drive could >> be accessed, INQUIRY returned sensible data etc. Those reset messages >> didn't appear on booting with the single-LUN quirk. Take a look at the >> usbmon logs below. So it seems the Iomega SCSI-USB cable needs >> US_FL_SINGLE_LUN. > > Indeed, all the messages attempting to probe LUN 1 failed. That's what > caused the resets. > > On the other hand, even with the SINGLE_LUN flag and a Jaz drive > attached, it didn't really work. Every TEST UNIT READY command got a > Not Ready; No Medium Present error response. That's almost certainly normal; when I captured the usbmon logs there was no disk in the drive. Hopefully I'll post a patch to add the single-LUN quirk for the Iomega cable to unusual-devs.h shortly. > But how much time do you really want to spend on this? Unless you've > got some highly important data stored on those old Jaz drives, it > doesn't seem worthwhile. The adapter connects at a measly 12 Mb/s > (which means transfer rates well under 1 MB/s in practice) and the > drives probably don't have a large storage capacity. A small USB flash > drive would hold more data and communicate much faster. Sure, for use with a modern system there's probably not much point except for curiosity's sake. But for imaging/copying data from old Jaz disks it's a convenient way to connect the SCSI drive to a modern laptop. It's also handy for data interchange with vintage SCSI-based computers (classic Mac, Amiga, etc.). Even at USB 1.1 speeds, imaging a 1GB or 2GB Jaz disk doesn't take a huge amount of time. [There were a few USB 2.0 SCSI converters, e.g. the Adaptec USB2Xchange and Ratoc U2SCX. But apart from being expensive they probably don't "just work" in Linux.] Mark -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
