What is (SMART) Self-Monitoring Analysis and Reporting Technology?

Self-Monitoring Analysis and Reporting Technology, or SMART refers to a fault-detection technique designed by IBM. This system uses different devices called sensors and methods to detect and notify the health of the disks of a hard drive.

Technically, apart from a diagnostic method to find the health status of a hard drive, SMART also signifies the interface between the storage device and the Basic Input Output System (BIOS) of the platform.

Understanding (SMART) Self-Monitoring Analysis and Reporting Technology

What is SMART

Typically, the diagnostic technology developed by IBM, Self-Monitoring Analysis and Reporting Technology or SMART, was introduced with the Advanced Technology Attachment 3 (ATA 3) specification.

It was designed to be used in their mainframe drives to provide advance warnings about its failures.

Initially, it was called the Predictive Failure Analysis, which is the main objective of this technology in the real sense.

However, based on this concept and technology, Compaq designed and submitted IntelliSafe to the ATA/IDE standards committees. The resulting standard was named SMART.

Mostly, SMART analyzes mechanical attributes to predict whether or not the hard drive is falling short of its tolerance.

Depending on the level of wear and tear of the hard drive, SMART can also predict the residual lifespan so that the users can make a decision whether they would take a backup of their data and continue using the drive or replace it.

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However, the technology cannot sense accidental or unexpected failures such as:

Still, it is a very useful feature to have and therefore most of the major Hard Disk Drive (HDD) and Solid State Drive (SSD) manufacturers include it in their system designs.

These companies include and are not limited to:

SMART is a part of the firmware of the hard drive, so it is something that you cannot download. It is typically found between the hard drive and the BIOS.

What is

Disk Self Test (DST) Types

Based on the features included, a hard drive can perform different types of SMART tests for different requirements such as:

Working Process

At the most elementary level, this technology operates on specific sensors and techniques to scan and monitor the health of the hard drive and then distinguishes into two broad categories such as:

Predictable failures comprise about 60% of total hard drive failures that are used in consumer systems and include:

Unpredictable failures are often the results of improper handling and misuse of hardware and therefore cannot be reasonably predicted.

Therefore, SMART typically concentrates on the predictable failures in particular. This is because these failures can be tracked easily and documented automatically.

SMART Fields

While in action, SMART examines the current status of the hard disk drives using several sensors to get measured values. These values are processed further by means of different algorithms which also modify the equivalent attributes based on the results.

Typically, these attributes have the following fields:

You may note at this point that more information may be displayed by the software with reference to these fields and may even help in evaluating or managing the attributes.

The Math Behind

The measured values or attributes are considered correct when the figure in the Value field is equal to or greater than that of the Threshold field.

Failure of the hard drive is predicted if, for a critical attribute, this is not true. The attribute determines the problem and the hard disk is considered to be bad and needs immediate replacement.

At this point, the SMART feature sends warnings to the users before they boot the operating system.

On the other hand, a failure of the hard drive cannot be predicted by the attribute if its Threshold is 0. This is because the Value cannot be less than 0.

Therefore, mathematically, an attribute is perfect in cases where this particular inequality is TRUE: A – f(r) >= C, where:

The problem with this calculation is that the A, B, C, and f function or values cannot be defined precisely. This is because they may vary from one model to another or even on two separate hard disks made by the same manufacturer.

Another notable downside is that the evaluation of the attributes is made independently, ignoring the relationship between them.

Status Check

Though SMART will notify about the issues 0n the hard drive, it is always a good idea to check the status of it manually and regularly, which can be done both on a Windows and a Mac computer.

On a Windows computer, you can check it by following these steps:

You will now have to create a system diagnostic report in the following way:

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On a Mac, you can check the SMART test results as follows:

The SMART status will be displayed as either “Verified” or “Failing.”

What Does SMART Do?

The primary function of SMART is to monitor the hard drive, its performance and detect the signs of its failure early and automatically.

And, in most cases, this technology will also notify you about the specific issue on the hard drive that it has detected.

The SMART utility will typically review all the vital IDs automatically to indicate the good or bad health of the hard drive in your computer system.

Ideally, SMART can show different attributes and information depending on the type of drive being used.

However, it is not an actual standard and therefore the meanings of each attribute may vary from one manufacturer to another.




Self-Monitoring Analysis and Reporting Technology is very useful for the hard disk drives because it lets the users know about the future issues in the drive early.

The technology is a part of the firmware within the hard disk drive that uses different methods and sensors to conduct different types of SMART tests.