*2.4.2 Availability*

The data were presented by Culnan's three dimensions of accessibility as a framework [10]:


Relative availability is the time when a system, or a component, should be operational at all when it is expected. A short phrase is that a system can continue to work even when the element or set of elements is gone. To measure reliability we must first measure availability.

Most reliability models are also predicted for hardware based on failure fracture rather than failures based on defects. In hardware, failure based on physical (corrosion) is more likely than design failure. The relationship between these key concepts of reliability in hardware and its application for software is specified. If we consider a computer system, a simple measurement of the reliability of the mean time between failures (MTBF) is displayed as follows.

In a transaction processing system, you may be concerned about system performance that is different from system levels, for example, consider the computer system one, A and the other is B. For the failure type, system A has an average time between two high failure MTTFs and has an average repair time (MTTR), but the failures are because of a large amount of files loss, and the system B has a short MTTF and a high MTTR. But loses of a small amount of data due to failure make user know that B is better than A although MTTF and MTTR and cost criteria may support the system.

**103**

*ANFIS to Quantify Maintenance Cost of IT Services in Telecommunication Company*

and for any type of purpose, many programs require a permanent failure.

One aspect of measuring the availability and reporting is definite scheduled time. To upgrade hardware, operating systems, databases and software, changing system and application parameters, data management, and backup to test failure

According to the theory, Stuart Rance and Hewlett Packard include the follow-

1.Collecting data from the service desk that specifies the job impact and the duration of each event, which is often not expensive, but there is little discus-

2.The tool of all the elements needed to provide services and calculate accessibility is based on understanding how an element is combined with the back services. This is an effective case, but it may lose intangible failures. For example, a small database failure may be due to the inability of users to deliver

Use a group of clients that sends known transactions from a point in the network

According to Stuart Rance and Hewlett Packard, the concept of "user definitive minutes" often measures and reports the number of affected users that is based on multiplying the number of users by the time the system that is out of reach in minutes is being impressed. The number of "user definitive minutes" is often compared with the number of "user potential per minute" to calculate a number for

Availability **∗ 100 =** (user failure minutes **−** user potential minutes)/

(user potential minutes) (1)

Accessibility is an indispensable part of to be considered. It is very necessary to understand what is and how it affects and how it is calculated. Although many methods are proposed to calculate the availability of a device and a simple system, calculating the availability of a business application in a complex organization can-

1.**Intrinsic accessibility:** When an item works satisfactorily in particular point under conditions in an ideal supportive environment, including logistics, waiting and regulatory failure, and preventive maintenance of the failure. This includes crashing maintenance. Intrinsic accessibility is generally due to the analysis of an engineering design, and the average of MTTF failure time calculation, which is divided by the average failure time plus the average time for MTTR repair based on design control, is

2.**Achieved accessibility:** When an item works satisfactorily in particular point of time under the declared conditions in an ideal supportive environment, for example, people, tools, and parts, which include logistic time, waiting, and

to determine what services are in progress and what they are doing.

*DOI: http://dx.doi.org/10.5772/intechopen.82827*

*2.4.2.1 Measurement of availability*

sion about the accuracy of the data.

specific types of transactions.

ing steps:

accessibility.

not be easily accessed [11].

calculated.

*2.4.2.2 Different types of accessibility*

*ANFIS to Quantify Maintenance Cost of IT Services in Telecommunication Company DOI: http://dx.doi.org/10.5772/intechopen.82827*

One aspect of measuring the availability and reporting is definite scheduled time. To upgrade hardware, operating systems, databases and software, changing system and application parameters, data management, and backup to test failure and for any type of purpose, many programs require a permanent failure.
