Notes

RAM can also be considered a hardware component called a storage device. A storage device is any hardware component that stores data,
either temporarily or permanently. When data is stored temporarily, short-term storage such as RAM is used. It's important to know that RAM is
considered volatile memory--it's not persistent. This means that when the power source is lost for example, the computer is turned off, all the
data that was stored in RAM is lost, it's gone forever. Now, you might be wondering why we would use a storage device that is erased every time
it loses power. Well the reason we use RAM is because it's extremely fast, information can be accessed from RAM faster than any other type of
storage hardware. But sometimes we need to store information permanently. This is done using long-term storage. Remember, short-term
storage is lost every time the computer is shutdown. Long-term storage however, is considered non-volatile memory--it's persistent. This means
that even when the computer is turned off, the data stored on the hardware will still be there when we turn the computer back on. There are a
variety of long-term storage media. The most common one is a hard-disk drive. Hard-disk drives store information on rotating disks called
platters. Another common medium is a solid-state drive or SSD. SSDs use memory chips that are a lot like RAM; however, the information stored
on these chips is persistent. Hard-disk drives and SSDs can store a lot of data and access it relatively fast but not nearly as fast as RAM. This is
why we use both hard drives and RAM to store data. We also have optical-storage media such as CDs, DVDs, and Blue-ray disks also called BDs or
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BRDs. Now, optical-storage media can either be read-only or writable. If a disk is read-only, the information it contains is fixed and can't be
modified or erased, it can only be viewed. An example of a read-only disk is a software CD-ROM or DVD-ROM. The ROM at the end actually stands
for read-only memory. Writable disks on the other hand can be modified. Disks that are writable have an R or an RW at the end. For example CDR,
DVD-RW, BD-R, the R stands for recordable. Unlike their ROM counterparts, these types of disks can have information saved to them. They are
two more long-term storage devices we need to talk about. The first is a flash drive, flash drives are small, portable devices that use memory
chips to store information. These memory chips are very similar to RAM chips; however, the information is persistent. The second is a secureddigital,
or SD card. You might be familiar with these. SD cards are used in smartphones, tablets and digital cameras to store information. They
use non-volatile memory.