There has been attempts to make hardware anti-virus but apparently it never took off.
By googling a little bit, I found the Xnet OS Protector and the Saming NetGuard and PCGuard but their descriptions look very dubious.
They claim to do stuff that are barely possible, especially at the times these cards were created (mid-90, I think):
- The most powerful feature is that the protected system files can be
recovered even when the CMOS setting is corrupted.
- Simple to install and use, no command, no programming, no script required.
- Protected data does not occupy any useable Hard Disk space, that means no other storage
media and devices are required.
- Recovers corrupted OS, software and eliminates virus, spyware, hackers with well protected disk image. As an option, the CMOS (that is, BIOS) setting can be protected as well.
- Recovery of 40GB data can be done in a minimum of 3 seconds but can take upto 8 seconds
- Can protect up to 2000GB of hard disk data.
If that was really possible, we'd all know about it and they would plenty of such cards on the market.
I couldn't find either reviews of these cards by reputable websites. I think we can definitely say it's snake oil...