I've got a few more ideas to talk about, but I thought it best to come through with what I said I would do next.
There are two trends going on with memory (for computers -- there is also some fascinating research going on about human memory) nowadays. The first trend is putting it elsewhere (in the "clouds") and the second trend is to eliminate the mechanical aspects of data storage and access.
I will push off the discussion of clouds to the next blog. We'll concentrate on the second trend.
There are a lot of excellent disk drives at the moment. The manufacturers have increased storage capacity, decreased the time to get to (access) the data, and greatly improved reliability.
Most improvements on disk drives have been associated with data density -- how many bits can be packed into the smallest area. The data density helps both storage capacity and transfer rates (the amount of time that is needed to move data from the storage device to working memory (or vice versa)). Blu-Ray disks work with a higher-frequency laser than do DVDs and DVDs use a higher-frequency laser than Compact Disks (CDs). The higher frequency means that the data density can be higher. Thus, Blu-Ray disks can hold more data than DVDs and DVDs more than CDs.
Further improvements are being made on materials, optics (the part that actually reads optical disks such as Blu-Ray), Wikipedia is a great source for more on specific formats and improvements.
What do these disks have in common? They have to move. In order to read (or write) the data, the reader ("sensor") must be over the datum. Usually, this means spinning the disk while the reader stays in the same place. Some magnetic hard disks have speeds exceeding 7800 revolutions per minute. However, movement means something to move it with and mechanical devices just will not work forever no matter how great the quality and design.
We now have many different electronic items -- phones, cameras, tablets, toys, and so forth that make use of non-moving memory. There are a lot of different categories for this, so lets just call them "flash" memory. In this case, there are still lots of data to access -- but the access method is built into the design of the memory device. Let's take a game cartridge as a simple example. The cartridge will contain data which can be addressed. It also has leads (usually copper) that connect to the game player. The game player makes use of these leads to address, and transfe,r the data. No physical movement (except for connecting the cartridge to the game player) is required. Another common example is a "memory card" which is inserted into a camera. Some printers allow photos to be directly printed from that memory card (taking the card out of the camera and inserting it into the printer).
Direct access memory devices are (currently) more expensive that disk drives -- but the cost continues to decrease as they become more popular and it is my opinion that they will take over for local storage eventually. Personally, I am still hoping for holographic cube storage as was seen in Star Trek.
Let it be so.
