Computers and Softwares in the Network

8/6/2019 Computers and Softwares in the Network

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Computers and Softwares in the NetworkTypes of Computer Hardware

Desktop ComputersMid range computers and ServersMainframe Computers

Desktop Computers

Desktops are currently the most affordable computers and ubiquitous in businesses, schools, and households; they are used forperforming office tasks, organizing digital photos, video editing, and Internet access. Nearly all desktop computers are modular, withcomponents that can easily be replaced or upgraded.Mid range computers and Servers

The term "mid-range" covers a wide range of computer systems that support more than one user, and may support many users. Itcovers an extensive range of computer systems, overlapping with desktop computers at one end, and mainframe computers at theother end. Mid-range computers include:

H igh-end Reduced Instruction Set Computer (RISC) CPU- based servers (IBM AS/400) Intel-based servers (Compaq, Dell, and H ewlett-Packard) UNIX-based servers of all types

M ainframe Computers

Mainframes (often colloquially referred to as Big Iron) are computers used mainly by large organizations for critical applications,typically bulk data processing such as census, industry and consumer statistics, and financial transaction processing.

The term probably originated from the early mainframes, as they were housed in enormous, room-sized metal boxes or frames.[1] Later the term was used to distinguish high-end commercial machines from less powerful units which were often contained insmaller packages.

Computer Software

Operating SystemApplication Software

Single User Applications Network/Multi User Applications

Management and Utilities Software

O perating System

An operating system (OS) is a set of computer programs that manage the hardware and software resources of a computer. Anoperating system processes raw system and user input and responds by allocating and managing tasks and internal system resources asa service to users and programs of the system. At the foundation of all system software, an operating system performs basic tasks suchas controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating networking andmanaging file systems.

Application Software

Application software is a subclass of computer software that employs the capabilities of a computer directly to a task that theuser wishes to perform. This should be contrasted with system software which is involved in integrating a computer's variouscapabilities, but typically does not directly apply them in the performance of tasks that benefit the user. In this context the termapplication refers to both the application software and its implementation.

M anagement and Utilities Software

Softwares describes the use of a system that constantly monitors a computer network for slow or failing systems and thatnotifies the network administrator in case of outages via email, pager or other alarms. It is a subset of the functions involved in networkmanagement.


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Cable Types

Coaxial Cables Twisted Pair F iber Optic Cables

Coaxial Cables

Coaxial cable was one of the first types of cable used in data networks and LANs.Coaxial cable used in LAN installations was designed to support Ethernet-type networks, permithigh data rates, and provide extra protection from electrical interference. Coaxial cable is moreexpensive and generally harder to install than other types of cables.

There are two primary options for coaxial cabling:10Base2 (Thinnet)10Base5 (Thicknet)

Twisted P air Cable

Twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company. Toreduce crosstalk or electromagnetic induction between pairs of wires, two insulated copper wires are twisted around each other. Eachconnection on twisted pair requires both wires. Since some telephone sets or desktop locations require multiple connections, twisted

pair is sometimes installed in two or more pairs, all within a single cable. F or some business locations, twisted pair is enclosed in ashield that functions as a ground. This is known as shielded twisted pair (STP). Ordinary wire to the home is unshielded twisted pair(UTP).

O ptical Fiber

An optical fiber (or fibre ) is a glass or plastic fiber that carries light along its length. Fiber optics is the overlap of appliedscience and engineering concerned with the design and application of optical fibers. Optical fibers are widely used in fiber-opticcommunication, which permits transmission over longer distances and at higher data rates than other forms of communications. F ibersare used instead of metal wires because signals travel along them with less loss, and they are immune to electromagnetic interference.Optical fibers are also used to form sensors, and in a variety of other applications.

Principles of Operation in F iber Optics

An optical fiber is a cylindrical dielectric waveguide that transmits light along its axis, by the process of total internalreflection. The fiber consists of a core surrounded by a cladding layer. To confine the optical signal in the core, the refractive index of the core must be greater than that of the cladding.

Types of O ptical Fiber

Multimode F iber Multimode fiber has a relatively large light carrying core, usually 62.5 microns or larger in diameter. It is usually

used for short Distance transmissions with LED based fiber optic equipment.

Single-mode F iber Single M ode cable is a single strand (most applications use 2 fibers) of glass fiber with a diameter of 8.3 to 10

microns that has one mode of transmission. Single Mode F iber with a relatively narrow diameter, through whichonly one mode will propagate typically 1310 or 1550nm. Carries higher bandwidth than multimode fiber, but

requires a light source with a narrow spectral width. Synonyms mono-mode optical fiber, single-mode fiber, single-mode optical waveguide, uni-mode fiber.

Network Tools

Common Network Tools: Modular Crimper LAN Tester Punch down Tool Wire Stripper Tone Tracer


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Hybrid Topology

With the hybrid topology, two or more topologies are combined toform a complete network. For example, a hybrid topology could be thecombination of a star and bus topology. These are also the most common in use.

Cellular Topology

One of the most recent and is used by the Telecommunications company.

Logical Topology

Also called signal topology A network computing term used to describe the

arrangement of devices on a network and how theycommunicate with one another

Types of Logical Topology

CSM A/CD CSM A/CA Token P assing

CSM A/CD

a transmitting data station that detects another signal whiletransmitting a frame, stops transmitting that frame, transmits a jam signal,and then waits for a random time interval (known as "backoff delay" anddetermined using the truncated binary exponential backoff algorithm)before trying to send that frame again.

CSM A/CA

Carrier Sense M ultiple Access (CSM A) is a probabilistic Media Access Control (MAC) protocol in which a node verifies theabsence of other traffic before transmitting on a shared physical medium, such as an electrical bus, or a band of electromagneticspectrum

Token P assing

Token passing schemes are a technique in which only the systemwhich has some "token" can communicate. The token is a control mechanismwhich gives authority to the system to communicate or use the resources of that network. Once the communication is over, the token is passed to the nextcandidate in a sequential manner.

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Computers and Softwares in the Network