Script:
Listen to a discussion between a student and her tutor.
W: My first test in computer science is on Monday, and I’m sure there′ll be a question about memory. So, can we go over memory again?
M: Sure. Just remember the term "memory” is used a bit loosely. It describes an important element inside the system unit—the part of your computer where information is stored. Technically, memory can be either of two things: RAM or ROM.
W: RAM and ROM—two kinds of memory. I need to be able to explain them. Now, what′s the difference between RAM and ROM?
M: RAM—or random -access memory—stores the programs and data you′re using in your current work session. When you turn off the computer, the information in RAM is lost. ROM—read- only memory— stores the information your computer needs to perform basic functions and run programs that are built into your computer ... like the program to start up the computer. ROM is permanent memory.
W: OK. You said RAM stores the programs and the data. OK, then what does the hard disk store? I guess I don’t understand the difference between the memory and the disk storage.
M: That’s a really good question. I′ll answer it with an analogy. Imagine you’re at the library, doing research for a new product your company wants to make. You′ve found a cabinet of one hundred file folders with all the information you need. You also have five sheets of instructions from your boss on how to use the information. So, what do you do? You sit down at a table, open several folders, and lay out only the instruction sheet you need for this part of tile research. After all, the library table is only so big. When you finish gathering data from the first set of folders, you put them back and get another bunch. Similarly, when you complete the first page of your boss′s instructions, you put that page back in your briefcase and pull out another page. Now, which part of your computer′s memory is sort of like the library table?
W: RAM?
M: That′s right. RAM. Why is that?
W: Because RAM stores only the program and data I need for this part of mv W0ĩkẳ RAM is sort of my work area—the tabletop—it’s what 1 use when I work with files in a program.
M: That′s right. And what are the one hundred file folders?
W: I get it now. The file folders are the disk storage. In a program, when I ask for another file, the computer gets it from the disk—the file cabinet—and loads it into RAM. What I mean is, it sort of puts the file on my work table.
M: That′s right! And by keeping in RAM only the files needed for your current work session, you can work much faster and more efficiently. When you’re finished, before you leave the library, you clear the table and return all the folders to the cabinet. It′s exactly like what the computer docs. When you finish your work session on the computer, all the files are returned to disk storage.