Re: Trying again: Question concerning Tiger->Leopard changes for unformatted BSD disk device.
Re: Trying again: Question concerning Tiger->Leopard changes for unformatted BSD disk device.
- Subject: Re: Trying again: Question concerning Tiger->Leopard changes for unformatted BSD disk device.
- From: Chris Sarcone <email@hidden>
- Date: Tue, 6 May 2008 15:28:33 -0700
Kyle --
I am writing a program to talk to a USB device that looks like an unformatted BSD filesystem (eg., /dev/rdisk?) -- by the way, that all works
(ioreg looks as exptected, I think). On Tiger 10.4.11, my (c++
command-line) applicattion can open the disk
(open(dev_path,(O_RDWR|O_EXLOCK)), and read and write to it. However, when
run on Leopard (10.5, 10.5.2), even as sudo, the application fails to open
the disk with a "Permission denied" error. The /dev/rdisk? shows up on
Leopard as read-only (on Tiger it's read/write for the owner, read-only for
group) and the Disk Utility says that the unformatted disk is "Locked" and
is not writable. The 'ioreg -l' display (IOMedia class) says the device is
'Writable' ( = Yes) in Tiger and is not writable in Leopard.
It sounds like this USB device does not properly support the SCSI Mode Sense command to determine its media write protect state. You might need to provide a Radar bug report for this device and we can do a workaround in the OS. It would also be nice to follow up with the USB Device Vendor and ask them to fix their firmware.
Thanks,
-- Chris
------------------ 6 Infinite Loop M/S 306-2MS Cupertino CA 95014 phone: (408) 974-4033 fax: (408) 862-7577 email: email@hidden
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