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Operating Systems OS X (Apple) Can I erase and start my mac with unix command Post 302566550 by bcarter5876 on Thursday 20th of October 2011 03:06:30 PM
Old 10-20-2011
Bad disc or drive

All current iMac models respond to the "c" key to request booting from the optical drive (make sure it is ONLY the "c" key, no shift, option, or command, or anything else). Automatically ejecting the disc usually means that it cannot read the disc at all. Check for scratches, and try a disc polishing/scratch removal system if you see anything heinous. It might also mean that your drive is having problems. There are a few other options, though, to get your system back up. You can hook up an external drive with an up to date version of the system software and boot from that by using the option key method mentioned earlier. This gives you the boot selector screen. The fact that your optical disc did not show up there either also indicates that either it cannot be read, or that it is not a valid boot device for your hardware. Are you sure it is the disc that came with the computer? Yet another method, if you have another Mac available, is to boot the iMac in "target disk mode" by holding down the "t" key at startup. This basically turns the iMac into a very expensive external hard drive. Then, you can hook it up to another Mac via firewire and install the system on to it from that Mac. There are some drawbacks to this method, but it will work well enough. After doing this, re-run the latest combo updater from support.apple.com.
 

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quotacheck(8)						      System Manager's Manual						     quotacheck(8)

Name
       quotacheck - file system quota consistency checker

Syntax
       /etc/quotacheck [ -v ] [ -f ] filesystem ...
       /etc/quotacheck [ -v ] -a

Description
       The  command examines each file system, builds a table of current disc usage, and compares this table against that stored in the disc quota
       file for the file system.  If detects any inconsistencies, it updates both the quota file and the current system copies	of  the  incorrect
       quotas.	Inconsistencies occur only if an active file system is checked.

       Normally,  returns a warning if it cannot find a valid quota file.  If you use the option, creates a quota file automatically and then per-
       forms its normal functions.

       If you use the flag in place of any file system name, checks all the file systems listed in to be read-write with disc quotas.

       Normally reports only modified quotas. If the option is supplied, will indicate the calculated disc quotas for each user  on  a	particular
       file system.

       The  command  expects each file system to be checked to have a quota file named in the root directory.  If none is present, will ignore the
       file system.

       The command is normally run at boot time from the file, before enabling disc quotas with For further information, see

       The command accesses the raw device in calculating the actual disc usage for each user.	Thus, the file systems checked should be quiescent
       while is running.

Files
       Default file systems

See Also
       quota(2), setquota(2), quotaon(8)
       ``Disk Quotas in a UNIX Environment,'' ULTRIX Supplementary Documents, Volume 3: System Manager

																     quotacheck(8)
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