INTRODUCTION
A few years ago, when some boot sector viruses had their glory, they often infected my disks, even to destroy my programs. I implemented my PC with a simple card to agains this viruses. But the program only to protect for some boot sector viruses and not for the file viruses. The idea is to protect the system when make a hot booting from the disk that contain a virus. This card also warning if a diskette contain a virus when the PC is accessing disk drive. It will warn too if the boot record from the disk that is being access has a non standard boot record. The standard boot record only can be add before the program was stored to the EPROM. I used an EPROM to store the program and the program can still be activated or deactivated by ask the user. I was drawn the layout diagram with ORCAD program and the layout PCB with SmArtwork program. I used I/O address at EOOO Hex. If you have a new ROM BIOS PC maybe this address had been used. Choose another I/O address that is still empty and make some modification to the program.
The program contained 2 subroutine. ie: serrum program and clock program. If you don't like the clock subroutine, it can be ommitted from the main program, but the bytes must be calculated again for the zero checksum. For more detail about this matter go to the PC prototype card section.
The schematic diagram can be seen below:
click to enlarge the images
And the PCB layout as follow:
click the image for zooming
Note :
New PC-AT design already add this feature in their ROM BIOS system. You can enable or disable this feature by selected the option from CMOS selectable area (virus warning). The concept is the same, the routine do not allowed any write to the boot sector area (boot record) or partition area (partition table).
My prototype hex dump can be obtain here.
2008 Upper Deck (UD) A Piece of History # 170 Polio Vaccine invented ( Historical Moment ) MLB Baseball Trading Card in a Protective Screw Down Display Case
A few years ago, when some boot sector viruses had their glory, they often infected my disks, even to destroy my programs. I implemented my PC with a simple card to agains this viruses. But the program only to protect for some boot sector viruses and not for the file viruses. The idea is to protect the system when make a hot booting from the disk that contain a virus. This card also warning if a diskette contain a virus when the PC is accessing disk drive. It will warn too if the boot record from the disk that is being access has a non standard boot record. The standard boot record only can be add before the program was stored to the EPROM. I used an EPROM to store the program and the program can still be activated or deactivated by ask the user. I was drawn the layout diagram with ORCAD program and the layout PCB with SmArtwork program. I used I/O address at EOOO Hex. If you have a new ROM BIOS PC maybe this address had been used. Choose another I/O address that is still empty and make some modification to the program.
The program contained 2 subroutine. ie: serrum program and clock program. If you don't like the clock subroutine, it can be ommitted from the main program, but the bytes must be calculated again for the zero checksum. For more detail about this matter go to the PC prototype card section.
The schematic diagram can be seen below:
click to enlarge the images
And the PCB layout as follow:
click the image for zooming
Note :
New PC-AT design already add this feature in their ROM BIOS system. You can enable or disable this feature by selected the option from CMOS selectable area (virus warning). The concept is the same, the routine do not allowed any write to the boot sector area (boot record) or partition area (partition table).
My prototype hex dump can be obtain here.
2008 Upper Deck (UD) A Piece of History # 170 Polio Vaccine invented ( Historical Moment ) MLB Baseball Trading Card in a Protective Screw Down Display Case
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