OS X fails to read from disk7 soon after unmount of disk7s2

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OS X fails to read from disk7 soon after unmount of disk7s2

Post by grahamperrin » Thu Nov 08, 2012 2:44 am

Maybe off-topic from general discussion of ZEVO but here goes …

Kingston DataTraveler G3 (flash) in either the frontmost or rearmost USB port of a MacBookPro5,2 running OS X 10.8.2. No ZFS on this device:

Code: Select all
sh-3.2$ diskutil list disk7
/dev/disk7
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *15.9 GB    disk7
   1:                        EFI                         209.7 MB   disk7s1
   2:                  Apple_HFS Mountain Lion template  14.4 GB    disk7s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk7s3


When I unmount slice 2 then attempt to cat disk7:

  • too long a pause by the end user, between diskutil unmount … and cat …, causes the cat-based command to silently fail.

If instead I act quickly, all blocks of the device are read without error. So I don't suspect an issue with the device.

Context: imaging a device. (More specifically: a .vdi of Mountain Lion to be used with VirtualBox without EFI.)

Current environment:

Code: Select all
DataTraveler G3:

  Capacity:   15.88 GB (15,879,634,944 bytes)
  Removable Media:   Yes
  Detachable Drive:   Yes
  BSD Name:   disk7
  Product ID:   0x1643
  Vendor ID:   0x0951  (Kingston Technology Company)
  Version:    1.00
  Serial Number:   001CC0EC3504BBB1670D01C0
  Speed:   Up to 480 Mb/sec
  Manufacturer:   Kingston
  Location ID:   0x24100000 / 4
  Current Available (mA):   500
  Current Required (mA):   200
  Partition Map Type:   GPT (GUID Partition Table)
  S.M.A.R.T. status:   Not Supported


screenshot 2012-11-08 at 07.45.36.png
screenshot 2012-11-08 at 07.45.36.png (184.41 KiB) Viewed 29 times


Why this topic in the ZEVO support forum?

For reference. Or to provoke thought about the ability of OS X (or its cat) to read from a device at certain times.

Meow.

An issue with firmware? I wonder.
grahamperrin Offline

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