Reliability, Availability, Maintainability RAM Concept Explained

Initial maintenance plans identify system level servicing requirements, on-equipment repairs, and planned maintenance levels. Resulting plans describe functional system design in sufficient detail to identify configuration, construction, interfaces, and features of repairables. Maintenance plans can be developed for a variety of operations including test support, (ii interim contractor support, contractor logistics support, depot, organization and intermediate, and automatic test equipment. Another reason why maintainability is a special aspect of software quality is that it acts as an enabler for other quality characteristics.

When a system has high maintainability, it is easier to make improvements in the other quality areas, such as fixing a security bug. More generally speaking, optimizing a software system requires modifications to its source code, whether for performance, functional suitability, security, or any other of the seven nonmaintainability characteristics defined by ISO 25010. An increase in maintainability can lead to reduction in operation and support costs.

What Is The True Meaning Behind Maintainability

Apparently, there are other factors that determine maintainability. In software development, the maintenance phase of a software system often spans 10 years or more. During most of this time, there is a continuous stream of issues that need to be resolved and enhancement requests that have to be met .

This kind of maintainability prediction analyzes how long repairs and maintenance tasks will take in the event of a system failure. Engineering provides inputs to alternative design concepts, support concepts, subcontractor/supplier proposals, and analysis of the effect of alternative manufacturing processes on maintainability. Later, when actual failure rate and maintenance time data become available from reliability and maintainability testing, manufacturing testing, or the user, the engineer can develop a figure for achieved MTTR. Analysis includes all the maintainability tasks addressed in the program plan. It translates overall system operational and support requirements into detailed quantitative and qualitative maintainability requirements and evaluates how many established maintainability requirements have been achieved.

There are several standards, best practices, and maintainability requirements that can be followed to ensure an asset is highly maintainable. Most of these guidelines can be broadly grouped under the following six categories. Reliability is the probability of an asset to perform its desired function under predetermined conditions for a set amount of time.

Ways are identified to increase quality or prevent future bugs from occurring . “Another important aspect of maintainability is that the accelerator should have very low beam losses, in order to avoid activation of the structure and to …” These example sentences are selected automatically from various online news sources to reflect current usage of the word ‘maintenance.’ Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. That said, automation tools help virtually every team maximize maintainability, no matter their preferences or background. Maintainability is a measure of how quickly and easily a resource can be fixed when something goes wrong.

Using CMMS to Increase Uptime

Here you’ll get most accurate definitions, close synonyms and antonyms, related words, phrases and questions, rhymes, usage index and more. A resource that has 99% availability, for example, is one that is up and responding 99% of the time. Availability, maintainability and reliability all have distinct—if related—meanings, and they each play different roles in reliability operations.

  • In this section, we discuss some misunderstandings about maintainability that are encountered in practice.
  • Availability also stands out because it is often the most important metric in defining SLAs and SLOs.
  • The maintainability engineer then works with the selected item principal engineer for scheduled maintenance time reduction.
  • In order to be reliable, a system requires both availability and maintainability.
  • A quality profile divides metrics into distinct categories, ranging from fully compliant code to severe violations.

In a sidebar at the end of each guideline chapter, we present the quality profile categories for that guideline as we use them at SIG to rate maintainability. Specifically, for each guideline, we present the cutoff points and the maximum percentage of code in each category for a rating of 4 stars or higher (top 35% of the benchmark). The second chart in Figure 1-1 shows the quality profile of a 2-star system. Notice that over one-third of the codebase is in units that are over 60 lines of code. The systems in the benchmark are ranked based on their metric quality profiles.

How to pronounce maintainability?

Maintainability is one of the key concepts for equipment manufacturers, operators, and asset managers. In its simplest form, maintainability means “ease of doing maintenance”. Likewise, when data indicates that a piece of equipment is no longer maintainable, an equipment upgrade may be necessary.

Any deviation from the set limits raises alarms to the operator who can then take necessary action and notify relevant personnel. They can use that info for the allocation of the required resources and for scheduling maintenance work, usually through a computerized maintenance management system . Scroll down to learn what is maintainability, can it be measured, and how asset design impacts the maintainability variable.

definition of maintainability

In software engineering, these activities are known as software maintenance (cf. ISO/IEC 9126). Closely related concepts in the software engineering domain are evolvability, modifiability, technical debt, and code smells. To learn more about this, please read the article below, and of course let us know if you need any assistance with your maintenance, maintainability, or reliability training programs. This is the first article in the series, and we’re going to keep it basic and foundational by giving a quick and easy definition of reliability and maintainability. The RMQSI Knowledge Center is a community resource for reliability, maintainability and quality products and expertise.

Where predictions suggest a failure to satisfy allocated values, the maintainability engineer must first determine which area of the design offers the best avenue for reduction of this figure. System or end item scheduled maintenance time is computed from detailed scheduled maintenance tasks by combining them in accordance with the process flow diagram and timeline diagram as noted above. In a deterministic environment, the estimated times are simply added where they are serially accomplished and critical path times added where parallel tasks are involved.

More from Merriam-Webster on maintain

Usually, the length of active repair time reflects factors such as product complexity, diagnostic adequacy, nature of product design and installation, and the skill and training of the maintenance staff. All in all, since active repair time is largely determined by the equipment’s built-in maintainability characteristics, the manufacturer of the equipment plays a key role in influencing how much active repair time is required. Maintainability depends on the product design and the technical level of repair personnel, the repair process, and the repair facilities.

definition of maintainability

However, an issue like this can fall through the cracks without the tools or processes to track these failures. However, when your team is busy and constantly pulled in different directions, this can be hard to do on the fly. This is where a maintenance app for tracking downtime comes in handy. To counter this, make sure your organization has a regular training program to identify potential skill gaps and support your team to become more adept in its role. Automated logistics Asset ManagementReduce downtime and improve productivity.

As the industry learns to code more efficiently (e.g., with the help of new technologies), the average for metrics tends to improve over time. What was the norm in software engineering a few years back, may be subpar now. The benchmark thus reflects the state of the art in software engineering.


Brush cutting, along with prescribed burning and grazing, are the primary tactics used to maintain – or increase – the number of grassland acres at the properties. There is no international database of honorary consuls, and many countries maintain poor records or release no information at all. It’s difficult to maintain a correspondence when we’re both so busy. Whenever an asset breaks down or malfunctions, the first step is to diagnose the root cause of the problem. If the root cause is not obvious, a lot of effort goes into the inspection and diagnosis of the faulty component.

Closing the Skills Gap with On-The-Job Training (OJT)

According to the ISO definitions, a system can be highly maintainable and still be lacking in other quality characteristics. Consequently, a system may have above-average maintainability and still suffer from problems regarding functional suitability, performance, reliability, and more. Above-average maintainability means nothing more than that the modifications needed to reduce the number of bugs can be made at a high degree of efficiency and effectiveness. Maintenance planning provides the necessary integrating input to the logistics engineering function to identify support requirements and resources for individual end items, subsystems, assemblies, and components. These requirements are then synthesized into maintenance plans for the overall system and they outline maintenance functions, flows, responsibilities, and actions.


Logistic time is that portion of equipment downtime during which repair work is delayed because a replacement part of other component of the equipment is not immediately available. Having irrelevant artifacts such as TODOs and dead code in your codebase makes it more difficult for new team members to become productive. Finally, the third chart in Figure 1-1 shows the unit size cutoff points for 4 stars. You can tell that Jenkins complies to the unit size guideline for 4 stars , since the percentages of code in each category are lower than the 4-star cutoffs. SIG divides the systems in the benchmark by star rating, ranging from 1 star to 5 stars .


One USB port can be used to connect a variety of different computer accessories with absolutely no compromises in functionality. The ASL fingerspelling provided here is most commonly used for proper names of people and places; it is also used in some languages for concepts for which no sign is available at that moment. DisclaimerAll content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only.

The data we have at SIG does not indicate that the technology chosen for a system is the dominant determining factor of maintainability. Our dataset contains Java systems that are among the most maintainable, but also, that are among the least maintainable. The average maintainability definition of maintainability of all Java systems in our benchmark is itself average, and the same holds for C#. This shows us that it is possible to make very maintainable systems in Java (and in C#), but using either of these languages does not guarantee a system’s maintainability.

Machine design can be made very efficient by incorporating complicated fault tolerance mechanisms, which can improve its inherent reliability. However, complicating the design can proportionally increase the time maintenance technicians have to spend on routine maintenance, reducing its maintainability. In an ideal world, all assets would be designed in such a way that they rarely fail and that they are easy and cheap to maintain. Since we do not live in a fairytale, we rely on Reliability, Availability, and Maintainability analysis to find a balance between asset productivity, purchasing, and maintenance cost. This article is a collaboration between the University of Tennessee Reliability and Maintainability Center , Convergence Training, and RedVector.

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