1. Supercomputer

3. Battery-powered CMOS (complementary metal-oxide semiconductor, pronounced ‘see-moss’) chips will not lose their contents when the power is turned off; this quality makes them useful for holding time and date information. It is also used to store start-up instructions. Unlike ROM, instructions held in the CMOS chip can be changed by the user (for example, changing the boot drive)
4. Flash memory is used to store flexible programs and can be erased and reprogrammed more than once. They are a type of PROM that can be altered easily by the user. It is nonvolatile memory that retains its contents after an electrical interruption, and it does not require a battery. The logic capabilities of these devices can be upgraded by simply downloading new software from the Internet ot a vendor- supplied disk to flash memory.
3. Types of topology
Networks can be laid out in 3 main topologies (physical structures):
1. BUS. In a bus topology, all nodes are joined along a shared connection. One problem with a bus topology is that there is no central management of data transmissions. If multiple nodes send data transmissions at the same instant, the data can “collide”. Too many data collisions at once, and the network goes down. This problem can be overcome by using Ethernet for the physical connections in the network.
2. STAR. In a star topology, a hub is placed in the center of the network, and each node connects to the hub individually. No single node's connection to the hub is affected by any other node. However, if the hub goes down, the entire network becomes inoperable.
3. RING. In a ring topology, all the nodes are connected one-to-another in a circle, so the last node is connected to the first (completing the circle). There is no danger of data collisions, because data only moves in one direction. However, if the connection goes down at any point, the circle is broken and the network become inoperable.
4. WAN, MAN, LAN, Intranet, Extranet
Networks come in all sizes, generally described in 3 terms: