However, fears of viral infection are ill-founded since these PDAs or telephones offer numerous obstacles to viruses. The operating systems of the handheld devices are stored in their ROM. The ROM is normally Flash so the user can update it to new versions of the system. Consequently, the biggest possible problem (in a hypothetical viral infection of one of these devices) is restoring the system from the ROM, a straightforward process which can be carried out by disconnecting the systemís battery.
The ability of the virus to spread depends on the system and the nature of the virus itself. Although it has already been verified that with PALM systems viruses can be created, as with Pocket PCs, such viruses can be removed simply by disconnecting the battery.
In spite of all this, it could be possible to devise a system capable of overwriting the device's Flash ROM. There are viruses, such as CIH, able to generate a copy of themselves modifying the Flash ROM. In handheld devices, the virus might be transmitted through the connection used to synchronize information with the desktop PC. In such a case, the virus would not be removed just by disconnecting the battery; a system ROM update would be necessary.
In the hypothetical case of a virus capable of modifying the ROM, it should spread from the desktop PC as with any typical email worm. If this were to happen, the traditional antivirus (installed in the computer with which the information is being synchronized) would detect and remove the threat.
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