Encrypt Sensitive Data

Many Nokia Series 40 and Series 60 phones include the Nokia Wallet application. On my Nokia 6600, the Wallet application is accessible via the Extras Wallet menu. The first time you use Wallet, you will be asked to create a wallet code, which is used to generate an encryption key. Then you can store small bits of data, such as web site passwords and bank accounts, in the wallet. The data stored in the Wallet application is encrypted and is accessible only to the person who knows the wallet code. On some recent phone models, the Wallet application can also integrate with the Services browser to save information you fill out on web forms.

If you key in an incorrect wallet code three times in succession, the Wallet application is blocked for five minutes. The next three incorrect entries of the code will double the blocking time.

If you need to encrypt entire datafiles on a Nokia Series 60 phone, third-party applications such as SmartCrypto from SymbianWare
(http://www.symbianware.com/product.php?id=scrypto60&pl=n6600) can help you. It encrypts any individual file on the Series 60 filesystem. Once the file is encrypted, you have to know the password to read its contents.

Protecting the Memory Card Data

The memory card on a Nokia device can store large amounts of personal data, such as pictures and other media files. Even with a locked phone, someone can still physically remove the memory card and potentially read its contents using a card reader. You can use a password to protect the memory card so that it cannot be used in other devices or card readers.
On a Series 60 device, you can lock the memory card via the Options>Set password menu in the Extras Memory menu. On a Series 40 device, you can set the memory card password via the Options>Set password menu when you select the memory card icon in the Gallery menu.

Locking the Phone

You can lock most Nokia phones (this is much more restrictive than locking the keys) by tapping the Power button, choosing "Lock phone" from the menu, and entering the lock code. Once the phone is locked, you can perform only two actions:

• You can tap the left soft key, which is labeled Unlock on the screen, and enter the lock code again to unlock it. If you are in the dark, tap the Power button to turn on the LCD backlight.
• If there is an incoming call, the locked phone will ring and you can take the call by pressing the green Call button.

If you just want to lock your keypad to prevent accidental dialing (or launching applications) when the phone is in your pocket, you can press the left soft-key and the * key at the same time. To unlock it, just press the left soft-key (or middle soft-key on devices with three soft-keys) and the * key again. No password is needed. Accidental dialing is especially a problem for phones that have the navigation pad sticking out like a joystick (e.g., the Nokia 6600).

You cannot dial any phone number or execute any application when the phone is locked. The default lock code in a factory-fresh phone is 12345. You can change the lock code in the Settings Security Phone and SIM Lock code menu on a Series 60 device or the Settings Security settings Access codes Change security code menu on a Series 40 device. On earlier Nokia Series 60 devices, you might find those settings in the Tools program rather than the Settings program.

Using the security settings, you can also configure the phone to automatically lock itself after a period of time .

Prevention

Protect your wallet and privacy by preventing unauthorized access, even when you do not physically possess your phone.

It is easy to lose a mobile phone. Most of us have had the experience of forgetting the phone on our desk or in our car. Our kid might take it to school, or our spouse might take it on a trip. Sometimes, the phone might even get stolen. A lost phone can expose you to big security risks, even if it is out of your physical control for only a couple of minutes:

Someone might be able to obtain the sensitive personal and business information stored on the device or someone might use the phone to make expensive calls or send messages to premier SMS service numbers and have the cost billed to you.

In this section, you will learn how to protect yourself against information theft and unauthorized service access when you lose your phone.

Remember to remove all locks, security codes, and personal data from your phone before you sell it on eBay! The best way to do this is to perform a hard reset and then format the memory card.

Backing up Applications

If you have installed your applications on the MMC card, they will still be available on the phone's Main menu after the deep reset. However, the Application Manager program might not keep track of them anymore. So, you might lose the ability to update or remove those applications. For the Application Manager to work, you need to copy the contents of the C:\System\Install\ directory to the E:\System\Install\ directory on the MMC card. Those directories contain the installers (i.e., the .sis archive file) of applications installed on the device. Since those system directories are not available in the Nokia PC Suite's phone browser, you have to copy them manually using a program such as FExplorer.

If you did not install applications on the MMC card and you have not backed up the entire phone memory using an automatic backup method covered in the previous section, you must reinstall all the applications from scratch.

Backing up documents

The best way to save documentssuch as the email messages, MMS messages, audio/video files, and imagesfrom being erased in a deep reset is to save them in the MMC card, which you can take out of the device when you do the deep reset. You can configure the Messaging and Camera applications to automatically save files to the MMC card.
If you do not save the phone documents in the MMC card, you can still copy and save everything in the phone's Gallery and Messages folders to a PC via the PC Suite before the deep reset.

Backing up PIM data

The phone's Personal Information Manager (PIM) data, such as contacts and calendar items, can be synchronized with PIM applications on desktop computers . You can synchronize them back to the phone after the reset.

If synchronization is not an option for you, you can use the backup and restore utility on the Nokia PC Suite, and request that it back up/restore the contacts and calendar data only.

Or, if you want to pick and choose which PIM items to back up, you can copy them to the PC via the Nokia PC Suite's phone browser. The PIM items appear as .vcf (for contacts) and .vcs (for calendar items) files on the PC. When you copy them back, the phone automatically converts them to the phone's internal format.

Manual Backup and Restore

The automatic backup and restore solution is easy and effective. But it requires discipline to back up your data regularly and to remember to back it up before each experiment. It is also less useful if the backup interval is too long and too much user data is changed between backups. In addition, if your phone is infected with a virus before the last backup and you have just noticed the virus now, how do you know which past backup is the clean one that can be safely restored?

Using manual methods described in this section, you will be able to selectively back up some of your phone data right before the deep reset, and then restore it after the reset. Here, I assume that you can still boot up your phone and operate it.

Even if your phone is fully functional and is not affected by malicious programs, you can still optimize the phone's memory by "refreshing" it. The manual backup process before refreshing gives you the opportunity to eliminate stale data and programs.

Backing Up MMC

You can back up everything in the phone's main memory to the MMC card via the Extras >Memory menu. Just choose the Options

Backup phone mem. menu and the data is backed up in a file, E:\Backup\Backup.arc, on the MMC card

When you decide to restore the phone memory from the backup file, just choose the Options Restore from card menu in the Extras>Memory menu. The phone will reboot itself after the memory contents are restored.

The Backup.arc file is written over every time you perform a backup. So, by default, you can recover to the phone state only at the last backup time. To work around this, you can copy the Backup.arc file off the memory card after each backup and archive it on your computer periodically. If you need to recover to an earlier date, you can copy the correct Backup.arc file back to the memory card and then perform the restore operation.

Backup and Restore Using the PC Suite.

The Nokia PC Suite allows you to back up the entire content of the phone's internal memory (the C: drive) to a PC file. The full backup file includes the following:

• Contacts
• Calendar items
• Documents such as notes, email messages, and MMS messages
• Images and other media files in the phone's Gallery
• Settings including GPRS access points, email, and other connection settings
• Personal preferences such as wallpaper, ring tones, and speed-dial shortcuts
• Applications including Symbian C++ and Java programs

I recommend doing the backup periodically. If you mess up and have to do a deep reset, you can locate the closest clean backup file and restore it to the phone via the PC Suite. The PC Suite puts your backup files into %SystemRoot%\Nokia\Phone Model\Backup (e.g., C:\Nokia\Nokia 3650\Backup for a typical backup for a Nokia 3650 phone).

The PC Suite also allows you to back up and restore a subset of data in the flash memory. You can choose any combination of the following four categories of data: contacts, calendar items, documents, and images.

Deep reset

Deep reset is not available on Series 40 phones, since user data and applications on those devices do not have direct access to the operating system, and hence, cannot crash the phone unless it is in bad shape in which case, you should have it repaired.

If you need to delete all the contacts or images on a Series 40 phone, you have to do it manually. The Nokia PC Suite provides a phone content browser that can help you speed up your cleaning procedures.

On a Series 60 device, a deep reset is equivalent to reformatting the C: drive and wiping out all the user data in the phone's internal flash memory. The data on the MultiMediaCard (MMC) card, however, is not touched. You can reformat the MMC card via the Options Format mem. card menu in the Extras Memory menu. You can force a deep reset on a Series 60 device in two ways:

If your phone can still boot up, you can enter the service code *#7730# in the idle screen.

If your phone does not boot into the idle screen, you need to hold the green Call key, the * key, and the number 3 key simultaneously while you power on the phone.

Although the MMC card should not be reformatted during a deep reset, you should probably take your MMC card out of the phone before doing a deep reset to be on the safe side.

You should see the word formatting on the screen during the deep reset.

It is very important that the phone has power while it is formatting. Do not take the battery out in the middle of formatting! In fact, I recommend that you connect the phone to an AC adapter before you do a deep reset.

Of course, after a deep reset "fixes" your phone's problems, you still need to restore some of the user data to make the phone useful again. That is more complex than simply resetting and requires you to plan a backup strategy before you start fiddling with the phone. Backing up and restoring give you the ability to roll the phone back in time to the stable and useable state before your latest failed experiments.

Normal Phone Reset

On a Series 40 device, you can do a normal reset via the Settings>Restore factory settings menu. The normal reset simply resets the most basic phone settings, such as the security code, whether to enable speed dialing, the display brightness, and the screensaver time-out, to their factory preset values. It does not alter the applications mapped to the right soft key (i.e., the GoTo key), nor does it alter any of the network connection settings.

On a Series 60 device, you can do a normal reset by entering the service code *#7780# on the phone's idle screen, as though you are making a phone call. Alternatively, you can use the Tools>Settings>Phone settings>General>Orig. factory settings menu to perform the normal reset.

The Series 60 normal reset does everything the Series 40 normal reset does. In addition, it forces the phone to reload all the .ini files from the Read-Only Memory (ROM) to the C: drive under the Symbian OS. Hence, many application settings are restored. For instance, a normal reset on a Series 60 phone restores the soft-key shortcuts on the idle screen to factory settings, deletes the phone's Bluetooth name, eliminates all the GPRS access point settings , and resets data storage options in the Camera or Messaging application to "Phone memory" . The email Inbox settings , however, are left untouched.

The phone prompts you for the current security code before it resets itself. The default security code is 12345.

On both Series 40 and Series 60 phones, the normal reset leaves intact all the user data on the phone, such as contacts, calendar items, wallpapers, images, tones, messages, and third-party applications. While it is a safe operation, the normal reset is of limited value, since most of the time it is the user data that messes up the phone. A much more powerful reset is a deep reset.

About Phone Reset

As a power user, you often need to fiddle with your phone to try out new software, experiment with new configuration settings, or even clear up viruses or other malicious programs. This fiddling can sometimes cause the phone software to crash, freeze, or otherwise behave abnormally (e.g., it will be unable to connect to the network or unable to run some programs). Some phone viruses discussed in "Avoid Malicious Software" can also freeze your phone. This is when the reset feature in Nokia phones comes in handy. In this hack, you will learn not only how to reset your phone, but also how to back up and restore data in a systematic manner.

How to Use Antivirus Software?

I've covered generic approaches to protect your phone and recover from an attack. But those approaches do not always prevent all attacks. Manually resetting the phone is time consuming and does not reverse the financial loss you might have incurred from the virus.

If you are really concerned about mobile viruses, you can invest in antivirus software to protect your phone. Antivirus programs for Symbian-based phones (e.g., the Nokia Series 60 smartphones) are available from the following vendors:

• F-Secure Mobile Anti-Virus from http://www.f-secure.com/products/fsmavs60/
• SimWorks Anti-Virus from http://www.simworks.biz/sav/
• Symantec Mobile Security for Symbian (beta) from https://www-secure.symantec.com/public_beta/

Like antivirus software on computers, mobile antivirus software scans all files on your device to look for specific patterns of known viruses (a.k.a. the virus signature). If it finds one, it isolates the infected file and presents you with the option to remove it.

The full device scan takes a long time and consumes a lot of battery power, so don't perform a full scan on a regular basis. To save time and energy, the antivirus programs support incremental scan modes that check only incoming files, such as files you've downloaded or created using software on your phone. After the first full device scan, the antivirus programs run in the background and automatically scan all incoming files from the Web, Bluetooth, MMS, and email messages, and check for virus signatures as they arrive. If they detect an infected program, you will be advised not to install it.

As you would expect, the key for a successful antivirus program is to have a complete list of virus signatures to check against. This is a moving target, since new viruses might be written after the antivirus software is released. So, all mobile antivirus programs come with a subscription service that allows the program to update its virus signature database periodically over the Internet via the phone's data connection.

How to Remove Virus from the phone?

If you know the name of the virus that infected your device, you can search for it via Google. You can probably find a lot of security bulletins from research sites such as http://www.symantec.com and http://www.f-secure.com. Most of these bulletins include a complete description of the virus, including the files it installs on your device. For instance, the following two URLs point to the F-Secure and Symantec bulletins for the Cabir virus:

http://www.f-secure.com/v-descs/cabir.shtml

http://securityresponse.symantec.com/avcenter/venc/data/epoc.cabir.html

With a file browser tool such as FExplorer, you can follow the instructions to remove the virus from your device.

In practice, it is difficult to know the exact name of a virus. For instance, the Cabir virus has at least eight very similar variations. So, the preceding method is not always practical in the real world. In most cases, a much simpler way to erase the malicious program and reverse the damage is to perform a deep reset.

If your phone has been infected with a virus and you do not know which programs are infected, it is probably a good idea to be conservative and install all third-party programs from scratch instead of simply reloading them from the backup.

Use a personal firewall

Most malicious mobile programs rely on the network to spread or work. You can prevent them by controlling the network connections on your phone. One of the most effective network control tools is a firewall. By installing a firewall on your phone, you can:

• Prevent unauthorized Bluetooth or General Packet Radio Service (GPRS) incoming connections and file transfers
• Prevent Bluetooth scanners from discovering or pairing with your phone
• Prevent Bluetooth scanners from accessing any data or services on your phone
• Prevent Trojans from sending out any information from your phone

The Symantec Mobile Security for Symbian (currently in beta) provides a personal firewall for Nokia Series 60 phones. You can download it from https://www-secure.symantec.com/public_beta/. Via the firewall, you can specify several different levels of communication constraints.

Bluetooth scanners.

Bluetooth scanners exploit insecure implementations of the Bluetooth system software on some phone models. Several Nokia phone models are known to be vulnerable (e.g., Nokia 7650, 6310i, etc.). You can get more information, including an updated vulnerable-device list, from http://www.thebunker.net/security/bluetooth.htm.

Bluetooth exploits were first discovered by Adam Laurie, of A.L. Digital Ltd., in 2003.

A Bluetooth scanner has to be physically close to your phone (e.g., in a conference hall or classroom) for Bluetooth to work. There are three known types of Bluetooth attacks:

Bluesnarf
This type of attack can be launched from untrusted (a.k.a. unpaired) devices. The attacker can steal information, including your Contacts list, calendar, photos, etc., from your phone.

Backdoor
This type of attack has to be launched from a previously paired device. The attacker can get access to almost all the functionality on your phone.

Bluebug
This type of attack involves creating a Bluetooth serial profile to your phone, and then hijacking the phone's voice and data connections.

Bluejacking
is often cited as a fourth type of Bluetooth attack. But it is really just a prank. It works as follows. The prankster creates a contact entry on her own phone and enters a prank message into the "name" field. For instance, the "name" of this contact might be "Your phone belongs to us." Then, the prankster sends the contact to random Bluetooth phones as a business card. The recipient suddenly sees an unsolicited prank message"Your phone belongs to us"on his phone screen.

Virus and Trojan that may attack your smartphone

Currently, all Nokia mobile phone viruses are written in Symbian C++ and are deployed to devices as Symbian programs. Although in theory Java-based viruses are possible, they are substantially more difficult to develop and deploy, since Java applications must run in the Java Virtual Machine and must conform to strict Java security policies. Since Java applications do not have direct access to your phone's physical memory or other low-level device-native features, it is less likely that they can breach or circumvent the phone's security policies. In fact, there is no known Java virus for Nokia phones. Since Java is the only programming platform on Nokia Series 40 devices, there are no known Nokia Series 40 viruses.

Mobile viruses and Trojans must be downloaded into your phone for them to take effect. Viruses and Trojans can spread in three primary ways:

Trojan download
The malicious program can present itself as a known (or appealing) Symbian program and trick you into downloading and installing it directly. For instance, the Mosquitos Trojan virus poses as a cracked version of the popular Symbian game, Mosquitos, on certain file-sharing networks. A cracked version of a game is a version that's been illegally modified to remove the registration module, so you can play it for free. The idea is that you'll run it, thinking you are running a game, but the Trojan virus will activate when you run it. Other examples include the Dampig virus, which pretends to a cracked version of the FSCaller application, and the Skulls virus, which pretends to be a theme manager application. To prevent Trojan viruses, you just need to be careful about the sources of the programs you download. I recommend that you use only legitimate software downloaded from well-known web sites. Beyond the immediate concern of security, it also helps if you don't try to circumvent copy protection, and instead, support the developers that work hard on software you want to use.

Bluetooth
Viruses can spread over the local Bluetooth network. An infected device tries to find all Bluetooth devices in its neighborhood, all the time. Once a device is found, the infected device sends the program over to the new device. The recipient is then presented with a message to accept the incoming file and install it. The original Cabir virus spread in this way. If the recipient is not well informed or if the message is deceiving, he might just install the program. For instance, the Gavno virus presents itself as a "software patch," borrowing a familiar concept from Microsoft Windows to deceive users. Once the program is installed, it can execute itself and then start to search for nearby Bluetooth devices to spread further.

MMS
A Bluetooth-based mobile virus can infect devices only within a range of several meters. Hence, the virus can travel only as fast as the devices move, which is the speed of airplanes in modern societies. Some newer mobile phone viruses, such as the Commwarrior, can spread over MMS. The virus tries to send itself via MMS to 256 random phone numbers from your Contacts list. This can potentially allow the virus to spread at the speed of telecommunications, which means it can spread across the world in a very short period of time. And what do you do when you receive an MMS from a friend? You open it, of course. This is the same kind of social engineering that permitted so many Microsoft Outlook-based viruses to spread over the years.

Some Nokia devices' Bluetooth implementations have known security vulnerabilities that allow files to be received without user acknowledgment. If this vulnerability is exploited by a Bluetooth-based virus, it can be extremely dangerous.

Malicious programs that may attack your smartphone

Before you can act to protect yourself, you need to know a little about how malicious programs can attack your mobile phone. The following is a list of representative malicious programs on smartphones and the harm they cause:

Force the phone to perform operations that interfere with regular user operations
The original Cabir virus (http://www.sarc.com/avcenter/venc/data/epoc.cabir.html) forces your phone to scan the Bluetooth network all the time, quickly draining the battery.

Disable some device functionality
The Dampig virus (http://www.sarc.com/avcenter/venc/data/symbos.dampig.a.html) replaces some key system libraries and makes many applications, including the Bluetooth user interface (UI), useless on your phone. The Locknut virus (http://www.sarc.com/avcenter/venc/data/symbos.locknut.html) can cripple your phone to the point that you cannot make voice calls. The Fontal.A virus (http://www.sarc.com/avcenter/venc/data/symbos.fontal.a.html) does not cause immediate problems for your phone, but it does secretly replace several key font files, which prevents the phone from booting up once you reboot it. Bluetooth scanners can send malformed Bluetooth messages to your phone and crash its Bluetooth program, forcing you to reboot your phone to recover.

Make phone calls or send Short Message Service (SMS) messages to expensive caller-paid services
The Mosquitos Trojan (http://www.sarc.com/avcenter/venc/data/trojan.mos.html) sends messages to premium SMS service numbers without your knowledge or approval. The message costs are billed directly to your service account. Some Bluetooth-based exploits allow a Bluetooth scanner running on a nearby device to remotely dial your phone or make arbitrary connections using AT commands.

Leak out sensitive personal information
Malicious Bluetooth scanners can allow a cracker to remotely steal the entire memory contents of your phone from another nearby device without your knowledge. In theory, it is also easy to develop a mobile Trojan that gathers information about your contacts, calendar, and media Gallery, and then sends the information to a third-party server on the Internet.


Cabir is the first virus known to target Nokia Series 60 devices. It is largely a proof-of-concept virus. Cabir spreads over Bluetooth and does not contain a payload (the malicious software that does the actual harm). It is benign, except for the fact that it drains your battery with continuous Bluetooth searches. Later variations of the Cabir virus, such as Cabir.b and Lasco, can do real harm to you and your phone.

Based on their attack methods, malicious software on smartphones can be divided into two categories:

Mobile virus or Trojans that are downloaded and installed into your smartphone

Bluetooth scanners that remotely exploit your phone from another nearby device

Memory management software for your smartphone

If you are really tight on memory, you can try some of the memory compression software solutions for Series 60 phones. The FExplorer tool discussed in "Explore the Filesystem" [Hack #20] can compress memory by moving fragmented storage units into a contiguous block. This operation typically increases available memory by 10%.

If the FExplorer memory compressor is still not good enough, Symbian software tools are available for compressing in-memory data and applications by up to 60% when they are not in use. These memory compression tools can expand the compressed files when they are needed. They essentially trade the persistent storage space for CPU processing cycles. Two popular data compression programs for Nokia Series 60 devices are:

ZipMan
ZipMan is a zip archive utility for Series 60 devices. You can build compressed archives of images, video clips, and other files from the Gallery. When you need to use those files later, ZipMan extracts them for you. You can download and purchase ZipMan from http://www.wildpalm.co.uk/ZipMan7650.html.

Space Doubler
Space Doubler compresses Symbian applications. It runs in the background to expand the compressed application on the fly whenever you try to execute the application. From the user's point of view, the compressed application behaves exactly the same way as the regular applications, except that the startup time is slower due to the extra expansion process. You can download and purchase Space Doubler from the following web site: http://www.psiloc.com/index.html?id=154.

In general, I do not recommend using these two solutions on a regular basis, unless you are desperate for space, since they slow down the device noticeably.

How to Reduce Logging in Your Phones?

Nokia phones can log all calls and network connections it initiated and received over a period of time. The default logging period is the past 30 days. While this is a very useful feature, the logging data can consume a lot of memory and slow down the device, especially if you make and receive a lot of phone calls.

You can reduce the size of the log by changing the Options > Settings > Log duration value in the Log application on a Series 60 device, or you can simply delete all log entries from the Log application when you need more memory space. On a Nokia Series 40 device, you cannot configure the log duration but you can delete log entries via the Call register > Delete recent call list menu item.

An introduction on memory cards

To expand the memory space available on the device, you can install a flash-based MMC card. The size of an MMC card can vary from 32 MB to 2 GBdepending on your encoding settings, 512 MB and larger cards should be sufficient for hours of movies or digital music. Most Nokia phones, such as the Nokia 6230, 3650, 6600, and 6620 smartphone, support the standard MMC cards you can buy from any electronics store. Newer Nokia phones, such as the Nokia 6630, 6670, 6681, and 6682 phones, support only a Nokia proprietary MMC format known as Dual Volt Reduced Size MMC (DV-RSMMC). The DV-RSMMC card is slightly smaller than the regular MMC card, but the former is more difficult to find and is more expensive. You should read your owner's manual or the phone specification on Nokia web sites to find out exactly what MMC card format your phone supports.

To install the MMC card, you can just insert it into a socket underneath the phone battery. For some devices, such as the N-Gage QD, the MMC card socket is located in an external card slot for easy access. Refer to your phone manual for the exact installation steps. Once the MMC card is installed, you can inspect its properties via the Extras Memory menu on a Series 60 device or the Gallery Memory card Options Details menu on a Series 40 device.

On a Series 40 device, you can view the status for both the phone's main memory and the MMC card via the Settings Phone settings Memory status menu.

Installing the memory card is the first step. To use the card, you should configure applications to store data on it. In the following list, I provide instructions for installing some key applications on a Series 60 device. Series 40 devices work similarly.

Gallery
The Gallery application now displays folders in both the phone main memory and the memory card. You can move files between the two storage units.

Application installers
When you install Java or Symbian applications, the installer asks you whether to put the application on the memory card. Please note that applications installed on a memory card still leave a small stub in the main memory. Also, the applications will stop working if the memory card is removed.

Camera, video recorder, and audio recorder
In the Settings menu of the Camera, Video Recorder, and Audio Recorder applications, you can choose "Memory in use," located between "Phone memory" and "Memory card." The captured media files are automatically saved to the appropriate folders in the selected storage unit.

Messages
In the Messaging application's Settings Other menu, you can choose "Memory in use" for saved messages. If you choose "Memory card" here, the phone saves all received SMS, MMS, email, and Bluetooth messages to the memory card. This feature is available only on Series 60 devices.

The memory card is a little slower than the built-in phone memory. The memory card stores persistent information. It does not store the dynamic data generated by applications at runtime.

If you use Bluetooth to send any file larger than 4 MB to the phone (this limit is lower on some older phones), you have to set the Messaging application's memory in use to "Memory card." If you do not do that, the message-receiving operation will be aborted by a "Memory full" error because the phone's main memory is only a couple of MB in size and cannot hold the received file.

Useful features of FExplorer

In addition to the file explorer, FExplorer supports some other cool features that you might want to check out. You can access all of those features via the Options menu
It allows you to take screenshots of the phone and save them to a specified directory in the Gallery.

• It can compress the memory to increase available storage space (i.e., defragmentation)
• It allows you to set and remove operator logos using appropriate image files
• It displays the phone information including model number, IMEI number, battery status, and software version number.
• It displays network information including the ID of your current cell base station and your service provider name.

The FExplorer program is a very useful tool, and I will use it again several times later in this blog.

Best of all it's free!!

Installation Packages Files Management

The installed Java MIDlets are located in the C:\ System\MIDlets and E:\System\MIDlets directories. You can find the .jad and .jar file pair for each installed MIDlet (see Figure 3-21), and you can open the .jad file and read its contents. The rms.db file contains the persistent storage data this MIDlet stores on this device.

For each installed Symbian application, the .sis installer is cached in the C:\ System\Install or E:\System\Install directory. The installed executable files and runtime configuration files are located in the C:\System\ Apps or E:\System\Apps directory.

You can use FExplorer to send the .sis, .jad, and .jar files to other devices. But make sure you have the proper rights to do so. On some devices, the built-in Digital Rights Management (DRM) system does not allow you to send out files with those suffixes. You can get around this by simply changing the filename to something else and then changing it back after sending.

Managing files received in the Messaging inbox.

In the C:\System\Mail\ directory, you can find all the messages you've received. The MMS, Bluetooth, IR, and email message attachments are stored as files in the nested subdirectories. The Mail directory might contain many cryptic subdirectories. The best way to locate a particular attachment file is to search for its name via the Options File Find menu.

This feature is especially useful when you need to access a received file that the device cannot recognize. For instance, suppose someone sends a PDF file to your phone via Bluetooth. If you have not installed a PDF reader application, the phone will not recognize this file and will not offer you an option to save it to the Gallery. But with FExplorer, you can locate the file and then send it via Bluetooth to a PC where you can read it. Or, you can copy it to the Gallery. If you install a PDF viewer on your device, you will be able to read it.

The media files

The C:\Nokia and E:\ directories contain all the top-level folders in the Phone Memory and MMC Card tabs of the Gallery).

So, why would anyone use FExplorer rather than the native Gallery to manipulate those media files? Well, for a couple of reasons:

1. FExplorer supports file search via the Options File Find menu. You can search the entire device or any directory using PC-style wildcards in filenames (e.g., scr*.jpg).
2. It is easier to move files to other directories using the Options Edit Copy/Paste menu in FExplorer than it is with the file move function in the Gallery.
3. FExplorer allows you to move nonmedia files into and out of any folders on the device. I will discuss this point in more detail in the next section.