Cannot unmount RAMdisk, computer won't reboot

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Level 2

245 points

Cannot unmount RAMdisk, computer won't reboot

Hi,

I'm having problems with RAMdisks on my MacPRO. Having 8 Gbyte of RAM, but none of my Applications supporting 64bit (even the Intel FORTRAN compiler is still 32bit!), I'm trying to access more memory by using a RAMdisk. I have no problem in creating and using them, but the application I'm using (IDL) does something strange on the files on that RAMdisk. Even if I exit the application I can't unmount the RAMdisk anymore.
Unfortunately, the only way to unmount the RAMdisk is to power off the computer ⚠. I can logout, but when I log in back again I find the RAMdisk still mounted. When I shutdown the system it gets hanging at the stage where disks are unmounted and I have to power off. Unmounting with -force does also fail.
Does anyone else experience such problems? Is there a way to enforce the unmounting of a volume which seems to be locked at the kernel layer?

Thanks everybody!

Thomas

Powerbook G4, 12 & MacPro 3GHz Dual core (2), Mac OS X (10.4.9)

Posted on Mar 23, 2007 4:48 AM

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Answer 1

a brody

Level 10

85,366 points

Mar 23, 2007 6:56 AM in response to Thomas Straus

RAM disks are not a normally supported function of Mac OS X. The software most typically used for RAM disks on Mac OS X is RAMBunctious. I would send them a technical support inquiry asking how to deal with the situation.

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Answer 2

Thomas Straus Author

Level 2

245 points

Mar 23, 2007 7:45 AM in response to a brody

RAMdisks are created with the system command 'hdid', so I can't believe they are not supported. But anyhow, I remember a month ago or so, I had a problem with a "normal" file created by mistake (I have to admit, always in the same application, IDL) of the order of 200 Gbytes which was impossible to remove, as the file was blocked somewhere at kernel level. In that case, the system was unable to unmount the disk, and not a RAMdisk, and the machine hung at shutdown. So, I was wondering, if there is a way to force an unmount in such cases, other than powering off.

Anyway, thanks for your reply!

Thomas

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Answer 3

a brody

Level 10

85,366 points

Mar 23, 2007 7:57 AM in response to Thomas Straus

The command line gets more tricky, as most people don't use that end of Mac OS X, albeit, as you'll see rm and other command line commands are mentioned in the knowledgebase. You might want to ask in the Unix part of the forum or read the man pages of hdid to see if there is something that can be done.

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Answer 4

Thomas Straus Author

Level 2

245 points

Mar 23, 2007 9:37 AM in response to a brody

Thanks, will try there...

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Answer 5

Mar 23, 2007 10:17 AM in response to Thomas Straus

Look at this link. http://osxdaily.com/2007/03/23/create-a-ram-disk-in-mac-os-x/

 Cheers, Tom

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