Saturday, August 11, 2007

A.T.M.


An automated teller machine (ATM) is a computerized telecommunications device that provides the customers of a financial institution with access to financial transactions in a public space without the need for a human clerk or bank teller. On most modern ATMs, the customer is identified by inserting a plastic ATM card with a magnetic stripe or a plastic smartcard with a chip, that contains a unique card number and some security information, such as an expiration date or CVC (CVV). Security is provided by the customer entering a personal identification number (PIN).

Using an ATM, customers can access their bank accounts in order to make cash withdrawals (or credit card cash advances) and check their account balances. Many ATMs also allow people to deposit cash or cheques, transfer money between their bank accounts, pay bills, or purchase goods and services.

ATMs are known by various casual terms including automated banking machine, cash machine, hole-in-the-wall, cashpoint or Bancomat (in Europe and Russia). The occasionally-used term ATM machine is an example of RAS syndrome.

History

An old Nixdorf ATMThe ATM was invented by Briton John Shepherd-Barron. The world's first ATM was installed in a branch of Barclays in Enfield, north London, in 1967. Reg Varney, from the television series On the Buses, was the first to withdraw cash. Inspiration had struck Mr Shepherd-Barron, now 82, while he was in the bath.

http://news.bbc.co.uk/1/hi/business/6230194.stm
A mechanical cash dispenser was developed and built by Luther George Simjian and installed 1939 in New York City by the City Bank of New York, but removed after 6 months due to the lack of customer acceptance.[1]

Thereafter, the history of ATMs paused for over 25 years, until De La Rue developed the first electronic ATM, which was installed first in Enfield Town in North London[2] on 27 June 1967 by Barclays Bank.[3]. This instance of the invention is credited to John Shepherd-Barron, although various other engineers were awarded patents for related technologies at the time.[4] Shepherd-Barron was awarded an OBE in the 2005 New Year's Honours List.[5] The first person to use the machine was Reg Varney of "On the Buses" fame, a British Television programme from the 1960s.[6] The first ATMs accepted only a single-use token or voucher, which was retained by the machine. These worked on various principles including radiation and low-coercivity magnetism that was wiped by the card reader to make fraud more difficult.[4] The idea of a PIN stored on the card was developed by the British engineer John Rose in 1965.[4]

ATMs first came into wide UK use in 1973; the IBM 2984 was designed at the request of Lloyds Bank. The 2984 CIT (Cash Issuing Terminal) was the first true Cashpoint, similar in function to today's machines; Cashpoint is still a registered trademark of Lloyds TSB in the U.K. All were online and issued a variable amount which was immediately deducted from the account. A small number of 2984s were supplied to a USA bank. Notable historical models of ATMs include the IBM 3624 and 473x series, Diebold 10xx and TABS 9000 series, and NCR 5xxx series

LOCATION


ATMs are placed not only near or inside the premises of banks, but also in locations such as shopping centers/malls, airports, grocery stores, petrol/gas stations, restaurants, or any place large numbers of people may gather. These represent two types of ATM installations: on and off premise. On premise ATMs are typically more advanced, multi-function machines that complement an actual bank branch's capabilities and thus more expensive. Off premise machines are deployed by financial institutions and also ISOs (or Independent Sales Organizations) where there is usually just a straight need for cash, so they typically are the cheaper mono-function devices. In Canada, when an ATM is not operated by a financial institution it is known as a "White Label ATM".

HARDWEAR

In North America, banks often have drive-through lanes providing access to ATMs.

An ATM is typically made up of the following devices:

*CPU (to control the user interface and transaction devices)
*Magnetic and/or Chip card reader (to identify the customer)
*PIN Pad (similar in layout to a Touch tone or Calculator keypad), often manufactured as part of a secure enclosure.
*Secure cryptoprocessor, generally within a secure enclosure.
*Display (used by the customer for performing the transaction)
*Function key buttons (usually close to the display) or a Touchscreen (used to select the various aspects of the transaction)
*Record Printer (to provide the customer with a record of their transaction)
*Vault (to store the parts of the machinery requiring restricted access)
*Housing (for aesthetics and to attach signage to)
*Recently, due to heavier computing demands and the falling price of computer-like architectures, ATMs have moved away from custom hardware architectures using microcontrollers and/or application-specific integrated circuits to adopting a hardware architecture that is very similar to a personal computer. Many ATMs are now able to use operating systems such as Microsoft Windows and Linux. Although it is undoubtedly cheaper to use commercial off-the-shelf hardware, it does make ATMs vulnerable to the same sort of problems exhibited by conventional computers

Wednesday, August 1, 2007

Distributed Operating Systems

Distributed Operating Systems:

The ODP standards, and this text, assume a model where distributed applications are running in multiple processes in multiple computers linked by communications. The application programmer will be supported by a programming environment and run-time system that will make many aspects of distribution in the system transparent. For instance the programmer may not have to worry about where the parts of the application are running, this can all be taken care of, if required; this is called location transparency.

There is another approach to supporting applications in a distributed system, that is by using a distributed operating system. On every computer system with an operating system the O/S provides an interface which the programs use to obtain services, such as input and output.

In a distributed operating system this interface is enhanced so that a program may be run on any computer in the distributed system and access data on any other computer. The operating system provides data, execution and location transparency, often through an extended naming scheme. The advantage of a distributed operating system is that is uses an interface below that of the application program. This means the existing programming environments may be used, the programmer may use the system with little or no extra training, and in some cases existing software may be used. The disadvantage is that a number of problems are left for the programmer and user to handle, for instance concurrency; and because of the advantage above, programmers are given little support for this. Essentially, the Distributed Operating System dictates the policies of distribution for all aspects of programming. This means that the programmer is not able to use the distributed functionality in an application specific way to optimize a solution.

Another major disadvantage is that the distributed system is tied to a style of operating system interface. There are lots of different operating systems today, to meet different requirements (real or imaginary); there is no reason why future distributed systems will not need different operating system interfaces. Consequently it is not possible to build a truly heterogeneous open distributed system by building it on top of an homogeneous distributed operating system.

The ODP model provides an application interface to the distributed system. This interface is extremely simple and is concerned with aspects of distribution only. The application may still be run on any local operating system that is appropriate.

The ODP model does include the use of distributed operating systems, but would require any particular type of distributed operating system to interwork with other types through ODP and with also with non-distributed operating systems. The applications would see no difference. One popular implementors specification for some parts of ODP is the Common Object Request Broker Architecture. This is covered in chapter 7.

Distributed Operating Systems and Algorithms integrates into one text both the theory and implementation aspects of distributed operating systems for the first time. This innovative book provides the reader with knowledge of the important algorithms necessary for an in-depth understanding of distributed systems; at the same time it motivates the study of these algorithms by presenting a systems framework for their practical application.

The first part of the book is intended for use in an advanced course on operating systems and concentrates on parallel systems, distributed systems, real-time systems, and computer networks. The second part of the text is written for a course on distributed algorithms with a focus on algorithms for asynchronous distributed systems. While each of the two parts is self-contained, extensive cross-referencing allows the reader to emphasize either theory or implementation or to cover both elements of selected topics.

Features:

*Integrates and balances coverage of the advanced aspects of operating systems with the distributed algorithms used by these systems.

*Includes extensive references to commercial and experimental systems to illustrate the concepts and implementation issues.

*Provides precise algorithm description and explanation of why these algorithms were developed.

*Structures the coverage of algorithms around the creation of a framework for implementing a replicated server-a prototype for implementing a fault-tolerant and highly available distributed system.

*Contains programming projects on such topics as sockets, RPC, threads, and implementation of distributed algorithms using these tools.

*Includes an extensive annotated bibliography for each chapter, pointing the reader to recent developments.

*Solutions to selected exercises, templates to programming problems, a simulator for algorithms for distributed synchronization, and teaching tips for selected topics are available to qualified instructors from Addison Wesley.

Distributed Operating Systems

Distributed Operating Systems

The ODP standards, and this text, assume a model where distributed applications are running in multiple processes in multiple computers linked by communications. The application programmer will be supported by a programming environment and run-time system that will make many aspects of distribution in the system transparent. For instance the programmer may not have to worry about where the parts of the application are running, this can all be taken care of, if required; this is called location transparency.

There is another approach to supporting applications in a distributed system, that is by using a distributed operating system. On every computer system with an operating system the O/S provides an interface which the programs use to obtain services, such as input and output.

In a distributed operating system this interface is enhanced so that a program may be run on any computer in the distributed system and access data on any other computer. The operating system provides data, execution and location transparency, often through an extended naming scheme. The advantage of a distributed operating system is that is uses an interface below that of the application program. This means the existing programming environments may be used, the programmer may use the system with little or no extra training, and in some cases existing software may be used. The disadvantage is that a number of problems are left for the programmer and user to handle, for instance concurrency; and because of the advantage above, programmers are given little support for this. Essentially, the Distributed Operating System dictates the policies of distribution for all aspects of programming. This means that the programmer is not able to use the distributed functionality in an application specific way to optimize a solution.

Another major disadvantage is that the distributed system is tied to a style of operating system interface. There are lots of different operating systems today, to meet different requirements (real or imaginary); there is no reason why future distributed systems will not need different operating system interfaces. Consequently it is not possible to build a truly heterogeneous open distributed system by building it on top of an homogeneous distributed operating system.

The ODP model provides an application interface to the distributed system. This interface is extremely simple and is concerned with aspects of distribution only. The application may still be run on any local operating system that is appropriate.

The ODP model does include the use of distributed operating systems, but would require any particular type of distributed operating system to interwork with other types through ODP and with also with non-distributed operating systems. The applications would see no difference. One popular implementors specification for some parts of ODP is the Common Object Request Broker Architecture. This is covered in chapter 7.

Distributed Operating Systems and Algorithms integrates into one text both the theory and implementation aspects of distributed operating systems for the first time. This innovative book provides the reader with knowledge of the important algorithms necessary for an in-depth understanding of distributed systems; at the same time it motivates the study of these algorithms by presenting a systems framework for their practical application.

The first part of the book is intended for use in an advanced course on operating systems and concentrates on parallel systems, distributed systems, real-time systems, and computer networks. The second part of the text is written for a course on distributed algorithms with a focus on algorithms for asynchronous distributed systems. While each of the two parts is self-contained, extensive cross-referencing allows the reader to emphasize either theory or implementation or to cover both elements of selected topics.

Features:

Integrates and balances coverage of the advanced aspects of operating systems with the distributed algorithms used by these systems.

Includes extensive references to commercial and experimental systems to illustrate the concepts and implementation issues.

Provides precise algorithm description and explanation of why these algorithms were developed.

Structures the coverage of algorithms around the creation of a framework for implementing a replicated server-a prototype for implementing a fault-tolerant and highly available distributed system.

Contains programming projects on such topics as sockets, RPC, threads, and implementation of distributed algorithms using these tools.
Includes an extensive annotated bibliography for each chapter, pointing the reader to recent developments.

Solutions to selected exercises, templates to programming problems, a simulator for algorithms for distributed synchronization, and teaching tips for selected topics are available to qualified instructors from Addison Wesley.

what is network operating system

A network operating system (NOS) is a piece of software that controls a network and its message (e.g. packet) traffic and queues, controls access by multiple users to network resources such as files, and provides for certain administrative functions, including security.

Note 1: A network operating system is most frequently used with local area networks and wide area networks, but could also have application to larger network systems.

Note 2: The upper 5 layers of the OSI Reference Model provide the foundation upon which many network operating systems are based.

Source: from Federal Standard 1037C

NOS was also the name of a proprietary time-sharing operating system on the CDC 60-bit 6000 and Cyber series mainframe computers; in the mid 1980s, NOS was replaced with NOS/VE on the 64-bit Cyber-180 systems.

Network Operating System (NOS) is an operating system that includes special functions for connecting computers and devices into a local-area network (LAN) or Inter-networking. Some popular NOSs for DOS and Windows systems include Novell Netware, Windows NT and 2000, Sun Solaris and IBM OS/2. The Cisco IOS (Internet Operating System) is also a Network Operating System with a focus on the Internetworking capabilities of network devices.

defination:

*Abbreviated as NOS, an operating system that includes special functions for connecting computers and devices into a local-area network (LAN). Some operating systems, such as UNIX and the Mac OS, have networking functions built in. The term network operating system, however, is generally reserved for software that enhances a basic operating system by adding networking features. Novell Netware, Artisoft's LANtastic, Microsoft Windows Server, and Windows NT are examples of an NOS.


Some of the features of Network Operating System are:

*Provide basic operating system features such as support for processors, protocols,
automatic hardware detection and support multi-processing of applications

*Security features such as authentication, authorization, logon restrictions and access control

*Provide name and directory services

*Provide file, print, web services, back-up and replication services

*Support Internetworking such as routing and WAN ports

*User management and support for logon and logoff, remote access; system management, administration and auditing tools with graphic interfaces

*Clustering capabilities;

Misconception

* A NOS is not the same as the networking tools provided by some existing OSs, Windows XP for instance. An NOS is an OS that has been specifically written to keep networks running at optimal performance.