Category: Apple

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Safe Mode for Windows and Mac

If your computer does not boot, there may be problems with drivers or write permissions. In order fix the computer, you can try to boot the operating system into safe mode. This overcomes many common problems that cause a computer not to boot.

Windows

In Windows Vista, Windows XP, Windows 98, and Windows 95, you get into safe mode by holding the F8 key at computer startup.

You then choose Safe Mode or Safe Mode with Networking as shown on this screen.

Mac OS X

Although it is not often used, the Mac has a safe mode too. Hold down the Shift key during computer startup.

For a recent Falls Church, Virginia customer I had to do this because the computer’s file permissions got screwed up. Once into the operating system with safe mode, I was able to use Disk Utility and repair permissions.

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Testing RAM

You should test new RAM to make sure that it works. You should also test existing RAM when your computer is acting weird. Computer RAM does go bad. When it does, you can see erratic behaviors such as computer freezes, incorrect screen drawings, and corrupted files. Most people assume that this is due to a virus.

A few years ago I saw a manager in a Reston, Virginia office reprimand an employee because the manager assumed that the employee somehow infected a computer with a virus. The important computer documents had been corrupted and could no longer be opened. We figured out later that the real culprit was just bad RAM that had incorrectly written the files to disk.

Testing RAM on a PC

Using a bootable CD such as Ubuntu or the Ultimate Boot CD as described in my Live CDs post will allow you to run utilities to test PC RAM.

Testing RAM on a Mac

Thanks to command-tab.com for creating a utility for thoroughly testing RAM on a Mac computer. Run their install package, shut down the computer, boot up while pressing the Command and S keys (to go into Single User mode), then type memtest all 2 in order to run the memory test twice.

I recently ran this test after adding more RAM to a computer for a Washington D.C. customer.  The test showed that the new RAM had no problems.

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Encryption on USB Flash Drives

USB Flash Memory Drives have become the replacement of the floppy disk.  You can get a 16GB flash drive for around $50 so they offer a great backup and travel option.  But what if you have your important data on it and you lose it?  Then whoever finds it will have easy access to all your data.  That’s why encrypting your data on a flash drive is so important.

Mac OS X Disk Utility

Some operating systems like Mac OS X have built in features to create encrypted volumes.  This can be done through disk utility.  You create a file of whatever size you want and that becomes a new mountable volume once you double click it and enter your password.  Without the password, you just see a single file that you can do nothing with.  This is a great option for Mac OS X but then if you find you need to access your files on Windows or Linux, you are out of luck.

TrueCrypt

The best multi-OS solution is TrueCrypt.  You can download versions of TrueCrypt for Windows, Mac OS X, and Linux.  You should then copy each of these versions to your flash drive.  Then you can run the appropriate version on whatever OS you are on.  With TrueCrypt, you can create an encrypted file of whatever size you want. Within the program, you can then select the file to mount it as an accessible drive.  In Windows, that means you’ll assign it to a drive letter.  On Mac or Linux, you should see the volume appear on your desktop.  Then use it like you would any other volume.  When you are done, you can unmount it and remove the flash drive.  

It does take these few extra steps of mounting your volume to get to your data but it is well worth the ability to access your encrypted data from any OS.  If your data is at all sensitive, you should definitely consider using TrueCrypt.

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iPhone Special Diagnostic Codes

Thanks to AppleGuy Tom for providing these codes which work on most US AT&T phones and have been tested on the iPhone. Simply type these codes as if you are calling them.

*3001#12345#* -Displays the Field Test Mode, network, cell, GPRS, call, and version information.

This picture shows the information from one of my cell towers. The Rx Level is showing the signal strength from that particular cell. Note that in Field Test Mode the signal meter in the top left corner changes from a 5 bar readout to a number. This is more accurate and can help when placing your antenna for a signal booster, for example.

*#06# -Displays the 15 digit IMEI (International Mobile Equipment Identity) in the middle of the screen. (This number is also printed on the back of the iPhone.)
This number is worth writing down. Your carrier can deactivate the phone with this number so that it will not work if ever lost or stolen, even when using another SIM card.

*#21# Displays ‘forwarding’ state (enabled or disabled) voice call, data, fax, SMS, sync data, Async data, packet access, and pad access forwarding for outgoing calls.

*#30# -Displays ‘Caller ID’ (enabled or disabled).

*#33# -Displays ‘barring’ state (enabled or disabled) voice call, data, fax, SMS, sync data, Async data, packet access, and pad access forwarding for outgoing calls.

*#43# -Displays ‘call waiting’ state (enabled or disabled) voice call, data, fax, SMS, sync data, Async data, packet access, and pad access forwarding for outgoing calls.

*#61# -Displays ‘call forwarding to voicemail’ state (enabled or disabled) [and number forwarded to] of voice call, data, fax, SMS, sync data, Async data, packet access, and pad access forwarding for outgoing calls.

To change the number of seconds before the call forwards to voicemail, retrieve your eleven digit number from *#61# then carefully type *61*numberRetrieved*11*30# -those last two digits are the seconds to ring (Default is 20; Max = 30)

*#62# -Displays ‘call forwarding when unreachable’ state (enabled or disabled) [and number forwarded to] of voice call, data, fax, SMS, sync data, Async data, packet access, and pad access forwarding for outgoing calls.

*#67# -Displays ‘call forwarding when busy’ state (enabled or disabled) [and number forwarded to] of voice call, data, fax, SMS, sync data, Async data, packet access, and pad access forwarding for outgoing calls.

*225# -Requests an SMS message displaying the current monthly balance. (if applicable)

*646# -Requests an SMS message displaying the remaining monthly minutes. (if applicable)

*777# -Requests an SMS message displaying the pre-paid account balance. (if applicable)

Some other AT&T codes currently do NOT work on the iPhone: *#4720# (voice quality reduction codec -to save battery) and  *3370# (better voice quality codec)

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When to buy Apple Products

You don’t want to buy a product just before it is replaced by a faster version at the same price. That’s why MacRumor’s Buyer’s Guide is useful for Apple products. It currently shows that there are many iPods and computers that are due for revisions soon based on the time since the last revision. This coincides with recent rumors of a September 9th event to announce new products.

This does not predict exactly when a new version will arrive.  Apple could come out with a small bump in the middle of a cycle. But if a revision is long overdue, you should consider waiting unless you need something immediately.