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Some Common PC-DOS Viruses and What They Mean To You

1.5 The Bouncing Ball Virus

The Bouncing Ball virus, also known as the Italian or Ping Pong virus, is another boot-sector infector, slightly different in operation from the Stoned and Joshi. The Bouncing Ball infects diskette boot sectors, and the DOS boot sector (rather than the master boot sector) on hard disks. The most obvious effect of the virus is that, approximately once in sixteen boots from an infected disk or diskette, a bouncing dot will appear on the display during the boot process and afterwards.

1.5.1 Spread

Although the details of infection differ, all the scenarios given for the Stoned virus apply to the Bouncing Ball virus as well. Shared machines, shared diskettes, and non-bootable diskettes may all serve as channels for the virus to spread.

1.5.2 Symptoms

Besides alerts from anti-virus programs, the main symptom of the Bouncing Ball virus is a bouncing dot on the display. But even this is not a completely reliable symptom; the virus only displays the dot when the value in the system clock at boot time has certain properties, and there may be systems on which the effect will rarely or never appear. As with the Stoned and Joshi viruses, an infected system has a bit less total memory than it should (because the virus reserves some memory at boot-time for itself), but the average user will not notice the difference.

1.5.3 Protection

The Bouncing Ball is another old and well-known virus, and any good anti-virus program should be able to deal with it. Removing the Bouncing Ball from a hard disk is somewhat simpler than removing the Stoned or Joshi. The SYS command will generally work even on an infected hard disk (since the virus infects the DOS boot sector, which SYS touches), although always re-check a disk after SYSing, to make certain. In some circumstances, SYS may not overwrite the boot sector, and a DOS FORMAT (after backing up all important files) or a special utility may be required. In any case, remember to turn the power off and reboot from a known-clean diskette before cleaning up.

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