WorldWide Drilling Resource

30 APRIL 2016 WorldWide Drilling Resource ® Losing Your Memory? So Do Computers! by Britt Storkson Owner, P2FlowLLC Do you think you are losing your memory? Please don’t feel like you are the only one this happens to. While computers are great, they have the same problem too. Everything has a finite useful life. This useful life may be measured in hundreds of years, but it’s still finite. Remember, memory is simply a collection of voltage states - 1s and 0s - organized in such a way so they have meaning to the user, and it’s called data. Much of what a computer does is manage memory. Not only does the computer need to know what the data is, but also where the data is so it can find it. Computers have different types of memory to serve different purposes and applications. Most of the time the type of mem- ory chosen for a particular task is cost-driven...meaning it’s the least expensive memory available that will work adequately for a given application. Like most anything you buy, there are different “grades” of memory. You get what you pay for. The other factor is speed. By memory speed, we mean how fast we can write to (replace existing data with new data) and read from (copy existing data to somewhere else). Some memory is very fast, others relatively slow by comparison. Generally, one uses “fast” memory for data that is rapidly changing and “slow” memory for data that isn’t changed very often. There are also trade-offs as the faster memory is volatile, meaning it is not retained after the power goes off, whereas nonvolatile memory is much slower. So we use both types and use the volatile memory for operations where we need the speed, and the slower nonvolatile memory when we need the information to be retained after the power goes off. In our computer controls, we use volatile for calculations which are updated (changed) several hundred times a second. We use nonvolatile memory for settings we want to store and remain unchanged for sometimes many years. A good example of this would be a thermostat setting. Turn on the heat when the temperature goes below a certain temperature, and turn it off when it goes above a certain temperature. The computer stores the selected temperature values in nonvolatile memory. While these values must be correct for sometimes many years, they must be adjustable too. Nonvolatile memory, while very good, isn’t perfect either. Like most everything, there are different grades of memory. Again, you get what you pay for. Nonvolatile memory data retention is called “endurance”, and time isn’t the only factor impacting endurance. The most common condition reducing endurance is ambient temperature. The higher the temperature, the less endurance you can expect from the memory. Also, some types of nonvolatile memory are altered by magnetic fields like the stripe on your credit card, so they must be shielded or otherwise protected from stray magnetic fields to meet the endurance specifications. Certain types of low power volatile memory can be made nonvolatile with the addition of a long shelf life battery, such as a coin cell. This gives us the best of several worlds: Memory which can be changed quickly and often, but is still nonvolatile because of the battery backup. Of course, the battery will wear out over time, but it is not uncommon to have these batteries last ten years or more. Also, it is possible for the computer to test the backup battery voltage to see if it’s still good and warn the user to replace the battery, but one cannot be certain the user will act upon this warning. Another downside is battery chemicals have been known to leak, often damaging nearby components, so there’s always that risk. Nowadays, memory is so reliable with our computer controls, the only thing we use a battery for is real time clock main- tenance (clock time). Time is dynamic and always changing, so it must have an external power source. There are very low power real time clock timing circuits out there and battery life of three or four years, but it’s still a battery and needs to be re- placed periodically. So the next time you think you are losing your memory, you can take comfort in the fact that even the best computers have the same problem. Britt Britt Storkson may be contacted via e-mail to michele@worldwidedrillingresource.com The new LETS 6.0 (Lateral Evaluation Television System) from Aries Industries, Inc. simultaneously inspects mainlines to 1000 feet and laterals to 150 feet. The slim unibody tractor design reduces pipe interference to maneuver quickly through harsh main- line pipe conditions. This versatile inspection system sets up quickly to match pipe contours. The basic six-wheel configuration operates in 6- to 12-inch mainlines. The powerful tractor has forward, reverse, and free-wheel movement. Its forward-facing camera captures mainline video and monitors lateral camera launch, and the rear-facing camera mon- itors both push cables when in reverse and during retrieval.