Have just installed 3.12.3 for mac OS X.
I can only get it to pick up 10 USB Block Erupters. The rest give me this, SEM: Icarus USB timeout waiting for (65547) '/tmp/cgminer-usb-20-10'
Any help would be muchly appreciated.
A usb failure can show up in so many ways, this is one of them. Likely there's just not enough power.
A fellow by the name of JimJag found the solution to this in
this post on the Asteroid forums.
The issue is that cgminer uses SysV semaphores and make use of the UNDO mechanism. OSX by default only allows 10 of these per process. Use sysctl to update to something more reasonable (eg: sysctl -w kern.sysv.semume=100). If cgminer has already been running, you'll need to do this via /etc/sysctl.conf and reboot.
The solution he suggests, can be implemented by running the following in your Terminal.app and then rebooting.
sudo touch /etc/sysctl.conf; sudo echo kern.sysv.semume=100 >> /etc/sysctl.conf; sudo chown root:wheel /etc/sysctl.conf; sudo chmod 0644 /etc/sysctl.conf