To input into the computer from a peripheral device (keyboard, mouse, disk, etc.) or the network. Like reading a book or playing a DVD, reading does not destroy what is read. The term also refers to accessing the contents of memory.
Every Read Is Also a Write
Every transfer of data is a "read" from one location and a "write" to another. Reading a sector in a hard drive means writing that data into memory. When data are copied from one memory area to another, the data are "read out of" one section of RAM and "written into" another part. See write