Answer:
Networking.
Step-by-step explanation:
An operating system which was developed in the 1950s, is a software which acts as an intermediary between the computer hardware and end users.
The functions of an Operating System are; Memory, Device, Process, File, Secondary-Storage and Input/Output management.
The networking component of the computer's operating system ensures that a group of processors don't share memory, clock and hardware devices, instead the processors communicate with each other through the network.
Basically, the network Operating System (OS) runs on a server and provides the capability to serve to manage groups, user, application or program, data, security and any other networking functions.
Hence, the accountant couldn't access the invoices that the sales department placed on the shared drive because of a networking component problem of the computer’s operating system.