Interface (Computing)
By definition, an interface is anything that allows two dissimilar systems to work together or communicate. In peripherals such as hard disk an interface is required to provide communication between the computer bus and the hard disk. The most popular interface used in modern hard disks is the IDE (Integrated Drive Electronics) interface, also known as ATA. Another commonly used interface is the SCSI (pronounced skuzzy), which is further divided into SCSI-1, SCSl-2, and SCSI-3. (a) IDE: The IDE concept was proposed by Western Digital...
read moreSecondary Storage Devices
CD-ROM, DVD, ZIP DISK, JAZ Drive, WORM, Magnetic tapes etc used to store data’s are known as Secondary Memory. Secondary memory can also be called as Backup Memory because they are used to store data and information for future use. Some of the Secondary Storage devices are described below: (a) Floppy Disk: In 1972, IBM lunched Floppy diskette in market to store data data and program. Floppy is made up with Mylar plastic or Polly vinyl plastic. It has concentric ring (tracks) and redial sectors to store data. Plastic is...
read moreComputer Memory
The computer memory is a data storing devices. There are many categories of memories: primary and secondary memory. RAM, ROM, registers, accumulator, floppy, hard disk, CD-ROM, magnetic tapes etc are example of computer memory. The processing capacity of computer not only depends on processor, but also on capacity of primary memory. The evolution of computer from one generation to next generation show variation in the processing speed, storing capacity, reliability, power consumption, and size. A memory system can be logically divided...
read moreCPU Registers
In computer architecture, a processor register is a very fast computer memory used to speed the execution of computer programs by providing quick access to commonly used values-typically, the values being in the midst of a calculation at a given point in time. These registers are the top of the memory hierarchy, and are the fastest way for the system to manipulate data. In a very simple microprocessor, it consists of a single memory location, usually called an accumulator. Registers are built from fast multi-ported memory cell. They must be...
read moreComputer System
The computer is designed to manipulate all types of data in the form of information. It is an electronic device in which data and control flow through bus in the form of digital pulse. It has mainly two parts: CPU and Pheripherals. (a) CPU (microprocessor): The Central Processing Unit of computer is called CPU. It is a brain of computer and its main components are: main memory, ALU and control unit. In 1972, Intel introduced 200KHZ 8008 chip, the first commercial 8-bit microprocessor. It accesses 16 KB of memory. The speed of...
read moreComputer Architecture
The first microprocessor chip was invented by Dr. Ted Hoff of Intel Corporation (USA) in 1969 and it become commercially available in 1971. It is a chief component of computer, without microprocessor computer is not computer but only pile of electromechanical, electronic and plastic materials beautifully connected to each other. The working mechanism of computer is not simple, it is a complex machine so, it’s working mechanism is also very complex for new comers. Here, only summery of working mechanism is presented in simple words: Main...
read moreBoolean Function
Boolean Function: A Boolean function is an expression formed with binary variables, the two binary operators OR and AND, the unary operator NOT, parentheses and equal sign. Example: Boolean function F1: (abc’) The function F1 is equal to 1 if a= 1 AND b=1 AND c’ =1, otherwise F=0. The Boolean function is represented as an algebraic expression. It may also be represented in truth table. Problem: Simplify the following Boolean function to minimum number of variables...
read moreUniversal Gate
The NAND and NOR gate are called to be universal gate because these are sufficient to implement any Boolean function. (a) NAND and NOR can do function of NOT, AND and OR gate. A NOT operation is obtained from a one-input NAND gate. Thus we find that a single-input NAND gate behaves as inverter. The AND operation requires two NAND gates. The first one produces the inverted AND and the second one being a single input NAND gate, acts as an inverter to obtain the normal AND output. The OR operation, the normal input A...
read moreNAND, NOR, EX-OR and EX-NOR Gate
The concept of NAND gate, NOR gate, Universal gate, Boolean functions, logic circuits or networks are explained briefly. These concepts are very important to grasp theme and theory of advance computer courses offered by several universities. NAND, NOR, EX-OR, EX-NOR gate: (a) NAND Gate: The NAND gate has two or more inputs signals but only one output signals. All input signals must be high to get a low output. Truth table: A B (A.B)’ 0 0 1 0 1 1 1 0 1 1 1 0 If the output of an AND...
read moreBoolean Algebra
Associated, Distributive, and Commutative Law are described below individually : Associated Law: There is no effect of ORing or ANDing operation on the method of variable grouping. (i)(A+B) + C= A+(B+C) (ii) (A.B).C = A.(B.C) Distributive Law: (B+C) = A.B+A.C Commutative Law: The input signals are transposed without changing the outputs. (i) A+B=B+A (ii) A.B=B.A Proof: (i) A+B=B+A If A+B=B+A If A=1, B=1 then LSH=1+1=1=B+A=RHS If B=0, B=0 then LHS=0+0=B+A=RHS If A=0, B=1 then...
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