Definition - What does RAM Disk mean?
A RAM disk is a representation of a hard disk using RAM resources, and it can take the form of a hardware device or a virtual disk. In software, it is basically a block of memory that is being treated as if it were a hard disk drive through the use of dedicated software, which takes a block from the RAM pool and uses it as a dedicated storage area as if it were a hard drive, but with exceedingly faster performance compared to a hard disk. In the form of a hardware device, it is just a bunch of RAM cards or sticks housed together in a case with drive electronics to make it interact with disk drive technologies such as SATA and IDE, and a backup battery so that data is not lost.
A RAM disk is also known as a RAM drive.
Techopedia explains RAM Disk
A RAM disk serves one purpose: to make I/O process performance faster and more efficient. Because RAM is the fastest type of storage, it makes sense to use it for storing data and programs so that they can be run and accessed faster. But the hurdle before was that RAM is a volatile medium and is used very differently compared to existing storage technologies, and so using it for this purpose would require completely new technologies. However, all it requires is some hardware interfaces, IDE and SATA, and a sufficient power source. Today, RAM disks are common, although not as prolific as regular hard drives and solid-state drives (SSDs), and come in a form factor very similar to those of hard drives and SSDs, ready to install inside a PC. These RAM drives actually use aftermarket RAM sticks or modules, which are installed with a 2.5- or 3.5-inch casing, which means that they can be replaced with faster and more expensive modules as long as the capacity is still supported by the drive electronics. But the biggest drawback for now is the cost, as RAM costs many times more per gigabyte compared to a standard hard disk.
When implemented in software, the RAM disk becomes more straightforward, as all it requires is the installation of a dedicated program to separate a specific portion of memory to serve as a hard drive. Although making programs work with the virtual RAM disk might need a little tweaking, which makes it something that only advanced computer users can do. But constant improvements in software ensure that, soon, a few clicks of the mouse are all it needs to set up a virtual RAM disk in a computer and have programs running from it.