Apple offers several alternative boot environments for OS X that can help you troubleshoot problems you might be experiencing, which can be invoked by holding various key combinations at startup. Of these, Safe Mode is perhaps the most common; it offers a limited boot environment and can be started by holding the Shift key. In addition there is Single User mode (Command-S) for a command-line interface, Apple's hardware diagnostics tests (the "D" key), Target Disk mode (the "T" key), and holding the Option key will bring up the boot loader for choosing a startup disk.… Read more
After making changes to the drive configuration in OS X you may run into an issue where the system will not boot as fast as it previously did. In these cases the system may sit at the gray boot screen for a while before the OS loads, but when it finally does, the system will otherwise run just fine.
This problem can happen after several types of drive configuration changes, which include replacing a faulty drive, upgrading the drive to a larger or faster one, or migrating to a new storage approach such as a custom Fusion Drive setup in OS X Lion or later.… Read more
Apple's Safe Mode option will boot OS X to a minimal environment where only a basic set of kernel extensions are loaded, disabling unnecessary services like Bluetooth and support for third-party add-ons that might be causing problems for your system. To get to Safe Mode, you simply hold the Shift key down at startup; however, there are times when systems might appear to be stuck in Safe Mode and always boot to it, regardless of whether you command it to do so.
If this happens, there are several approaches you can take to tackle the problem.Reset PRAM In … Read more
When you boot a Mac system you have the option to supply keyboard commands at startup to boot the system to alternate environments. For instance, a common option is to hold the Shift key to boot to Safe Mode, but you can also hold Command-V for verbose mode (a text output of items as they load), or Command-S for Single User mode, which drops you to the command line as the "root" user so you can perform troubleshooting tasks.
In addition to keyboard commands at startup, you can use the "nvram" terminal command to set a … Read more
Often when troubleshooting systems, you might wish to boot into Safe Mode to run in a minimized boot environment to test if a third-party extension or add-on is causing problems with your machine. In addition, booting to Safe Mode also runs some cleaning and maintenance routines on your system, which can help iron out problems.
Most people know about using the keyboard to boot to Safe Mode, by pressing the Shift key down after hearing the boot chimes, and holding it until you see the grey Apple icon with the spinning indicator below it. You may also see a progress … Read more
After updating your OS you may find a number of small issues with programs not functioning properly or some system services not working. As we noted earlier, some people have had difficulty with iTunes freezing after updating to OS X 10.6.7, but in addition some other people have found their Bluetooth devices such as the Magic Mouse and Magic Trackpad have not been able to connect.
When these types of issues occur, sometimes basic resets can clear the problem and cause the system to properly recognize the available services. The basic resets are to restart the computer (using … Read more
Many users are aware of some boot commands for Mac OS X that provide different functionality for your system. The following is a more comprehensive list of the keyboard commands you know and many you may not.
A recent tweet from @superfetz reminded me of several boot commands I've learned over the years, so I thought a more comprehensive list would be useful for MacFixIt readers.
While you cannot run any code from Terminal or otherwise to set an order of boot devices, you can easily control where your Mac boots via keyboard commands. The following key combinations can … Read more
When troubleshooting various aspects of OS X and Mac hardware, one common routine is to boot into Safe Mode to automatically run some maintenance routines and prevent the system from loading inessential features. This can be done by holding the Shift Key immediately after hearing the boot chimes when starting the system up; however, sometimes this may not work.
Booting to Safe Mode requires the Mac's firmware to send the kernel some variables (boot arguments) that it interprets as a command to modify the procedures it uses to load the rest of the system. These can be set manually … Read more
Samsung has begun producing a new chip that one day may replace flash memory and that is expected to increase cell phone battery life by more than 20 percent.
The world's largest maker of memory chips said that it is now manufacturing phase-change random access memory (PRAM) in 512-megabit (Mb) capacities.
Phase change memory has been discussed for decades. Intel co-founder Gordon Moore, for instance, wrote an article about the technology that was published in the September 1970 issue of Electronics magazine. And the basic way the technology works hasn't changed. In phase change memory chips, a medium … Read more