WorldWide Drilling Resource

Northern Plains Chapter of the ISEE President: Billy Obermire Tel: 307-689-0050 www.bitwconference.org 29 WorldWide Drilling Resource ® MARCH 2015 Black Hills Chapter of the ISEE President: Doug Hoy www.bitwconference.org Digital Doldrums by Britt Storkson Owner, P2FlowLLC Digital technology is wonderful. It allows us to gather, store, and recall large amounts of information quickly, cheaply, and reliably. So just how does this technology work? As mentioned in previous WWDR aticles, it’s really quite simple. It all starts with the bit. A bit is a memory location containing voltage, or no voltage. If voltage can be measured at this memory location it is defined as a “logic one (1)”. If no voltage can be measured it is defined as a “logic zero (0)”. So a bit is simply a voltage stored on silicon. Using 5-volt digital logic, where the system voltage is +5 volts and ground is 0 volts, generally a logic “1” is defined as 2.4 volts or greater and a logic 0 is 0.8 volts or less referenced to ground. Digital signals should always be either at the system voltage or ground for sta- ble operation. These bits representing 1s and 0s are organized (typically) in rows of 8 bits, which is called a “byte”. All of the bytes are numbered in sequence from 0 to whatever the memory capacity is so we can find the information we store there. A “byte” is a binary (base 2) value with 256 possible unique states...2 raised to the eighth power. The value is offset by 1 because 0 is included, giving us dec- imal values from 0 to 255. Binary values are usually written in groups of four digits...1s or 0s, to make them easy to read. They are written starting from the right and moving left as the value increases, just like we write decimal numbers. Any decimal value can be expressed in binary, and there is no limit to how many digits we can use. The right-most binary digit is called the “least significant bit” (LSB) and the left- most binary digit is called the “most sig- nificant bit” (MSB). This type of memory is called Static RAM. RAM is an acronym for “Random Access Memory” and it is volatile mem- ory. Volatile means it requires a power source to maintain this memory, because if the power goes off (meaning if the supply voltage goes to zero), and then back on again even for a split second, the values are not retained. There will still be 1s and 0s in there, but they will be corrupted...not what we put in there. While the downside of this type of memory is it requires power to maintain it, the upside is it requires very little power...in the order of nano-amperes... billionths of an amp. Maybe a little more, depending on how much memory we must maintain. Static RAM is also very fast and cheap. Static RAM has many uses because often one does not need to maintain every bit of data when the power goes off. Static RAM, while very reliable when properly maintained, like everything, is not perfect. Once in a while, we will find cells or “bits” that do not retain their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torkson cont’d on page 30.