Disk
drives are particularly vulnerable because a single catastrophic failure can annihilate data (and business) in fractions of a second. The goal of using smart sensors to improve overall reliability, accurately forecast failure, and allow for prefailure mitigation bound together major drive vendors, including Conner, Seagate, Quantum, Western Digital, IBM, and Cheyenne. This consortium used IntelliSafe, pioneered by Compaq, to develop a disk reliability standard, called Self-Monitoring, Analysis, and Reporting Technology (SMART). SMART has on-drive sensing hardware to report drive status, plus optional software to receive and interpret that data. The SMART consortium enhanced IntelliSafe, adding elements of IBM's Predictive Failure Analysis technology, and generalizing it so a broad range of storage devices could use it.
One category of hardware failure is highly predictable because it is the result of gradual and quantifiable physical degradations in device performance. SMART -- today a part of virtually
every new drive shipped -- provides prior notice to users and network administrators when it detects an imminent failure. (The computer or network monitor must have the software end to receive and interpret what the drive sends.) The exact prediction method varies with drive type and manufacturer, but basically it works this way:
Drives have sensor chips that monitor key parameters, storing values in their small local memory. SMART can track over 200 possible parameters, but most devices watch a small subset of these. These parameters com-
monly include head flying height, throughput performance, spin-up time, seek-error rate, seek-time performance, and drive calibration retry count. When any fall outside specified ranges, the drive sends an alarm. With luck, someone's listening. Administration software can access the stored parameter values, sense any alerts, and initiate actions, like warning the user or administrator. Compaq's Deskpro line can detect imminent-failure SMART alerts and back up t
hreatened data automatically.
Action at a Distance
Printers use many diagnostic sensors, for good reason. Computers without printers are basically space heaters, so it's important to keep printers up and running. Especially when administrators are trying to monitor and maintain printers from remote locations.
The Minolta Color PageWorks 3000 is one such printer. It tracks things like toner level, paper jams, and whether the cover is closed. All these things can show up at the administrator's console. When a user calls to say the printer isn't working, the administrator can look at one screen and suggest, for example, closing the cover.
Hewlett-Packard provides similar diagnostic and reporting systems for a wide range of its products. A single screen can monitor the status of many different types of HP printers.
Future Smarts
Expect this trend toward embedded diagnostic hardware to continue. There is a desire to keep overall costs down. That means both anticipating pro
blems and fixing them expeditiously. There is the need to manage components remotely. This need will become even more important as embedded components gain Web consciousness, thanks to embedded software companies like emWare. There is the goal of homogenizing hardware components, to simplify upgrades and maintenance. Finally, there is the aim to deter or detect theft of components.
Smart embedded hardware can help in all these areas.
Embedded Diagnostic Hardware
