The Complete Codes

View of Data The system hides certain details of how the data are stored and maintained and such view is an abstract view. The Database System provides users with an abstract view of the data.

Topology means the physical design of a network including the devices, location and cable installation. Logical Topology refers to the fact that how data actually transfers in a network as opposed to its design.

Computer Network | Ethernet (802.3) Ethernet is the most widely-installed local area network (LAN) technology. Ethernet was originally developed by Xerox from an earlier specification called Aloha net and then developed further by Xerox, DEC, and Intel. An Ethernet LAN typically uses coaxial cable or special grades of twisted pair wires. Ethernet is also used in wireless. Ethernet is standardized as IEEE 802.3 that specifies a CSMA/CD bus network. CSMA/CD (Carrier Sense Multiple Access / Collision Detect) is used to detect the collision in the network. An Ethernet CSMA/CD can be implemented using a Bus or even a Star topology.

Why CISC? •            Compiler simplification? –           Disputed… –           Complex machine instructions harder to exploit –           Optimization more difficult •            Smaller programs? –           Program takes up less memory but… –           Memory is now cheap –           May not occupy less bits, just look shorter in symbolic form •            More instructions require longer op-codes •            Register references require fewer bits •            Faster programs? –           Bias towards use of simpler instructions –           More complex control unit –           Microprogram control store larger –           thus simple instructions take longer to execute –           It is far from clear that CISC is the appropriate solution

Theory Of Computation | (TOC)Moore Machine Moore machine is an FSM whose outputs depend on only the present state. A Moore machine can be described by a 6 tuples M = ( Q, Σ, Δ, 𝛿, λ, q 0 ) Where, Q = finite set of states. Σ = finite set of symbols called the input alphabet. Δ = finite set of symbols called the output alphabet. 𝛿 = input transition function where  𝛿 : Q✕ Σ →Q   λ = output transition function where   λ :  Q → Δ q 0 = initial state from Where any input is processed ( q 0 ∈Q).

Theory Of Computation (TOC) | Eliminating  Epsilon Transition ( ε -Transitions) : Given any Epsilon NFA (ε-NFA) , we can find a DFA D that accepts the same language as E. The construction is close to the subset construction, as the states of D are subsets of the states of E. The only difference is that dealing with ε-transitions, which can be done by using ε-closure.

NFA with Epsilon( ε) Transition (ε-NFA): The NFA with epsilon-transition is a finite state machine in which the transition from one state to another state is allowed without any input symbol i.e. empty string ε. Adding the transition for the  empty string doesn’t increase the computing power of the finite automata but adds some flexibility to construct then DFA and NFA. This are very helpful when we study regular expression (RE) and prove the equivalence between class of language accepted by RE and finite automata.