Probability And Permutations

One of the first areas that everyone is introduced to in the study of statistics are the concepts of Probability and Permutations.
Probability is usually referred to as odds by most people and the coin toss is the introduction to the concept.
A coin is generally considered to have two sides: One Heads One Tails. So is the coin is tossed into the air and it lands with one of those sides facing up what are the “odds” or probability of that being the side called heads?
possible outcomes is 2, either Heads or Tails.
Tossing the coin ONCE means only one of the possibilities will occur and they both are just as likely to occur.

Memory explained

As soon as the computer became “personal” or personal computer (PC) the memory and storage descriptions got confused.
Originally, the memory used to run programs inside of was called RAM (Random Access Memory), it was volatile memory (meaning when the power got turned off to the PC the memory lost everything in it.
So storage systems came out to store programs in them so you could use them again when you wanted to. I remember having to retype programs in to run them before I had a storage device.
First personal computers used cassette tapes for storage, then came programs stored on “data cartridges” by the manufacturer that you would buy (the first video game consoles used these and some still do.
Then came floppy disk for storage and then hard drives which led to compact disc (CD->DVD->Blu-ray) to make Hard drives find information faster memory was added as a cache (temporary storage) on the drive itself until this technology got sufficiently inexpensive and storage began to be made from just those electronic memory parts.
The problem is this is where it gets confusing.
Original ram stored data as a charge in a cell like a super small battery that needed power on all the time to check regularly the cell level and either drain off small power or refill it (called refresh cycle) to keep it set as full or empty (1 or 0).
Then the cartridge memory used a method that didn’t require that power checking because it would flip like a switch, but that took a lot of power in the beginning and so it was done rarely or only during manufacturing when the data was put into the memory.
The Physical devices didn’t have the power on always requirement and could only be read or written to when the power was on otherwise they mostly stayed in the state they were last in.
So the confusion comes from new developments that combine parts or the memory of ram volatility with the switch memory of cartridges to create a bunch of different technologies that don’t have the power need to refresh the memory nor the high power requirements of the cartridge memory…..FLASH memory.
Variations of this memory family is used in USB sticks (USB Flash Drives) and SSD (Solid State Drives) these can have data written to them and never changed (used to hold the operating system for tablets) and as storage space for programs and data.
Generally a variation of the original RAM (volatile memory) is still used to actually run and hold the program when it is being used. But some devices actually use a variant of Flash memory for running programs too.
A tablet now-a-days may be listed as 16GB of memory–actually they mean storage not usable memory to run programs just store data, music, videos etc. and 512 MB to 4GB memory to run the programs in.
IPads are currently 512mb to 1GB memory to run programs and 16GB storage space that also contains the operating system so you may see 12GB usable listed. Meaning the Operating system occupies 4GB of the storage space.
Windows RT and Windows 8 Pro and Surface tablets took a lot of complaints because the operating system left only 23GB of storage of a 64GB memory tablet.
Beware: Android is not exempt.
Android 4.x onward redefined memory usage and while the micro SD expansion slot allowed more storage space for android devices. Previous android version allowed that memory to be used as direct storage that the programs could easily access and use. Android 4.x redefined the micro SD memory as external storage so many programs required the user to move the data into the devices storage memory from micro SD memory. Work a rounds have been getting created by developers to again allow their programs direct access to this additional memory storage. That sort of explains why google nexus devices don’t have micro SD slots though doesn’t it.