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.

4 thoughts on “Memory explained”

    1. I originally wrote this in response to the confusion everyone seems to have with Tablet and Smart Phones advertised and incorrectly commented on specifications.
      The memory topic has gotten so blurred, it takes a very careful read to understand what is actually being offered.
      I posted a smaller comment on a tablet website and decided it may be of interest to people here for when they will want to use apps I write to perform some of the statistics and math functions, in the learning process.

  1. Why do they call this memory when it is clearly storage? It’s like calling all pets dogs and it is extremely hard to have conversations with people who don’t understand how a computer works and insist that they have 16 GB of memory on their tablet.

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