Self-Monitoring, Analysis and Reporting Technology facts for kids

Self-Monitoring, Analysis, and Reporting Technology, or S.M.A.R.T. is a special system inside computer hard disks. It helps watch over your hard drive to prevent it from failing suddenly. S.M.A.R.T. checks the drive's health to see if problems might happen soon. This way, it can warn you before you lose important data.

How Hard Drives Fail

Hard drives can stop working in two main ways:

• Predictable failures happen slowly over time. This is like parts wearing out or the storage surface getting old.
• Unpredictable failures happen very suddenly. This could be an electronic part breaking or a sudden mechanical problem.

S.M.A.R.T. is good at finding predictable failures. Think of it like a thermometer in a car engine. It warns the driver if the engine gets too hot, so they can fix it before serious damage occurs.

About 60% of hard drive failures are due to mechanical parts wearing out. Before a drive completely breaks, it often shows signs. These signs can include getting hotter, making more noise, or having trouble reading and writing data. It might also have more damaged areas on the disk.

The main goal of S.M.A.R.T. is to warn you that your drive might fail. This warning gives you time to save your data. For example, you can copy everything to a new drive. About 30% of failures can be predicted by S.M.A.R.T.

Even though S.M.A.R.T. is helpful, some studies show it doesn't always predict every failure. However, certain specific warnings from S.M.A.R.T. are very important. If a drive has its first error when scanning, it is much more likely to fail soon.

Over time, S.M.A.R.T. has gotten better. At first, it just watched the drive's activity. Later, it added automatic scans to check the drive even when it wasn't being used. The newest S.M.A.R.T. technology not only watches for problems but also tries to fix small errors.

A Brief History of S.M.A.R.T.

The idea of monitoring hard drives started a long time ago. In 1992, IBM created a system called Predictive Failure Analysis (PFA). It checked key parts of the drive. It would simply tell you if the drive was "OK" or "likely to fail soon."

Later, a company called Compaq worked with drive makers like Seagate and Quantum. They created a system called IntelliSafe. This system allowed the drive to send more detailed health information to the computer. Each drive maker could choose what to measure.

In 1995, Compaq suggested IntelliSafe become a standard for everyone. Other companies agreed, and they worked together to create the S.M.A.R.T. standard we use today.

What S.M.A.R.T. Tells You

The most basic thing S.M.A.R.T. tells you is its "SMART status." This is usually just two messages: "drive OK" or "drive fail." If it says "drive fail," it means the drive might not work correctly in the future. This could mean it stops working completely or just gets slower.

The SMART status doesn't tell you about past problems. If a drive had issues but is now working fine, S.M.A.R.T. might still say "OK." Also, if a drive breaks completely, you might not be able to get its SMART status at all.

Sometimes, a drive might have trouble reading certain areas. This doesn't always mean it's about to fail. For example, if the power suddenly goes out while the drive is writing, it might create a bad spot. Modern drives can often fix these bad spots by using spare areas.

S.M.A.R.T. also uses "Attributes." These are specific measurements of different parts of the drive. Things like temperature, how many times the drive has started, or how many errors it has found. Each drive maker decides what these attributes mean.

Drives with S.M.A.R.T. can also keep "logs." The error log records recent errors the drive reported to the computer. This helps you see if computer problems are related to the disk. The self-test log keeps results from special tests the drive runs on itself. These tests can find unreadable areas, helping you recover data from backups.

How S.M.A.R.T. Works with Computers

Many computer motherboards can show a warning message if a hard drive is about to fail. While S.M.A.R.T. is a standard, each hard drive maker uses it a little differently. They might have their own secret ways of checking things.

S.M.A.R.T. is mainly about how the drive talks to the computer. This means a drive can say it supports S.M.A.R.T. even if it doesn't have every sensor you might expect, like a temperature sensor.

Sometimes, S.M.A.R.T. data doesn't work well with all connections. For example, external drives connected by USB or Firewire might not send S.M.A.R.T. information correctly. Also, if you use a RAID system (which combines multiple drives), S.M.A.R.T. programs might not see the individual drives. This can make it hard to get warnings.

On computers running Windows, many S.M.A.R.T. monitoring programs only work if you are logged in as an administrator.

S.M.A.R.T. Attributes Explained

Each hard drive manufacturer sets its own S.M.A.R.T. attributes. These are like specific health checks. Each attribute has a "raw value" (what the drive actually measures, like temperature in degrees Celsius). It also has a "normalized value" from 1 to 253. A value of 1 means the worst condition, and 253 means the best. A value of 100 or 200 is often considered normal.

Many big hard drive companies use S.M.A.R.T. attributes, including Samsung, Seagate, IBM, Fujitsu, Maxtor, Toshiba, and Western Digital.

Predicting Failure Dates

Some S.M.A.R.T. software can try to predict a "Threshold Exceeds Condition" (TEC) date. This is a guess at when a critical health measurement might reach a dangerous level. If software reports a "Nearest T.E.C.," it's like a "Failure date."

This prediction is based on how fast an attribute's value is changing. However, TEC dates are just estimates. Hard drives can fail much sooner or last much longer than the predicted date.

Images for kids

• 

  An mSATA SSD, a type of solid-state drive.

See also

In Spanish: S.M.A.R.T. para niños