It was really easy to erase or damage files, completely destroy the data on a disk and, on an Apple II, cause misalignment of the Disk II disk by repeatedly crashing the head against the drive armature. On a PC with an CGA/MDA you could damage the monitor power supply by putting the CRTC in a mode incompatible with the video input. Legend says you could make smoke go out of an MDA monitor.
At that time, it was also much harder for viruses to propagate - they would have to infect files and disks. Also, most IIs were booted from the application floppy and were thus completely stateless: whatever the virus did in the last session would have no effect on the next one.
Comments
It was really easy to erase or damage files, completely destroy the data on a disk and, on an Apple II, cause misalignment of the Disk II disk by repeatedly crashing the head against the drive armature. On a PC with an CGA/MDA you could damage the monitor power supply by putting the CRTC in a mode incompatible with the video input. Legend says you could make smoke go out of an MDA monitor.
At that time, it was also much harder for viruses to propagate - they would have to infect files and disks. Also, most IIs were booted from the application floppy and were thus completely stateless: whatever the virus did in the last session would have no effect on the next one.