WorldWide Drilling Resource

Computer Memory Compilation by Britt Storkson Owner, P2FlowLLC There are many different types of computer memory for different applications or cost considerations. Most of the time, the decision to use which memory for what application is based on using the least ex- pensive memory available which will adequately service the task at hand. Right now, the least expensive memory for nonvolatile (memory retained after the power goes off) storage of large amounts of data for computer use is the hard drive. This uses a spinning disk and a stylus to magnetically store information on the disk. The advantage is lowest cost per memory byte stored, but the mechanical disk is not suited for high vibration applications, such as aircraft. Solid-state hard drives are available for it, but at a much higher cost. For data backup, the “flash drive” which plugs into the USB port on the computer is becoming popular. This is nonvolatile memory with an “endurance” of about 100,000 erase/write cycles. This works very well for limited read/write applications, such as backing up files where the memory isn’t being altered very often. In fact, one would certainly wear out the USB connector by pushing it in and out of the socket long before it reaches its 100,000 erase/write cycle limit. All memory is numbered from 0 to whatever number the size of the memory is. This number is called an “address”...where it lives...just like your home address is where you live. Not only do we need to know what the data is, it’s critical to know where the data is. One of the big breakthroughs in the development of the computer was the operating system which manages memory. Much of what a computer does is store and recall memory, and this numbering system is critical because the computer needs to know where to find the data it contains. And all of these memory locations are numbered in binary (base 2) because it’s what computers deal with internally...just ones and zeros. The numbers go from all zeros to all 1s. So if you have what we call “1K” (1 Kilobyte or 1000 bytes) of memory, all of the memory locations are numbered from 0 to 1023 decimal or 00 0000 0000 to 11 1111 1111 binary. It’s all powers of 2. In this case, it’s the number 2 raised to the 10th power or 2^10 because there are 10 binary digits. It’s also called “10” bit because there are 10 bits in the data “word”. Memory is so necessary for what we do and has become so cheap, we’re routinely buying megabytes, gigabytes, and terabytes of memory. Amegabyte represents 1 million bytes of memory. It’s 2^20 bytes of memory, and these are numbered from 0 to 1,048,575. A gigabyte is 1 billion bytes of memory. It’s 2 raised to the 30th power or 2^30 or 0 to 1,073,741,823 bytes of memory. And if gigabytes of memory were not enough, we’re quickly moving into terabyte territory. The prefix “tera” is derived from the Greek word for “monster”. A terabyte is 1 trillion bytes of memory. It’s the number 2 raised to the 40th power or 2^40. These are numbered 0 to 1,099,511,627,775. Like human memory, no computer memory lasts forever, but we’re seeing 40+ years of data retention in many applica- tions, which is quite good.Also, if onemem- ory is having problems, we can quickly transfer the memory to a new storage medium and effectively extend our data retention capabilities. So when someone asks you to recall certain information, don’t just rely on your memory. Use the computer! Britt Britt Storkson may be contacted via e-mail to michele@ worldwidedrillingresource.com Happy Mothers Day! Sunday, May 8, 2016 To all the moms out there... 28 MAY 2016 WorldWide Drilling Resource ®