In general, they depended on their host operating systems for everything else, from disk mapping to security.
Then the user/client can access the host system from another computer using the installed software.
A serial port requires very little supporting software from the host system.
The process will continually be repeated if the virus is not removed completely from the host system.
Another reason is because accurate details of sector position are hidden from the host system.
These were intended for installation in a host system such as a Sun-3 workstation.
They all feel heavy in one way or another, either performance or size, impact on the host system.
And in doing so, you have taken it away from your host system.
Their main purpose is to make its host system open to access through the internet.
They connect to their host system using an 8-position 8-conductor connector, however only the middle 4 positions are actually used.