This same network can also be used as a general test bed in which all network upgrades and so on can be tested before attempting them on the real network. Total prevention entails the sealing of all external drives and the isolation of external network interfaces, for example routers. Read only access permits users to insert their disks but prevents them from storing this information on the network based servers. Clearly, both techniques have advantages as well as serious disadvantages. These systems will scan all of the internal disks whenever a workstation is 'booted' and will scan external drives whenever a disk is inserted.
Infected disks result in the ejection of the disk or in the workstation being disabled.
Virus scanning software is an essential application for all workstations, whether they are networked or not. The final point to consider is that in most cases the addition of various secure features has very little effect on the performance capability of the network but does increase the 'boot' time of the workstation, cause by virus scanning, disk mirroring, access confirmation and the 'down-loading' of the user's work environment. It is accepted practice to try to use internetworking hubs to house these in modular rack systems. Minimise one-off costs by allowing for substantial expansion, for example by using structured cabling. Do not equate provision for cabling access with necessarily supplying the full cable.