CompTIA A+ Certification All-in-One Exam Guide

Figure 3-14 RAM as a spreadsheet
• Any individual 1 or 0 = a bit
• 4 bits = a nibble
• 8 bits = a byte
• 16 bits = a word
• 32 bits = a double word
• 64 bits = a paragraph or quad word
The number of bytes of RAM varies from PC to PC. In earlier PCs, from
around 1980 to 1990, the typical system would have only a few hundred
thousand bytes of RAM. Today’s systems often have billions of bytes of
RAM.
Let’s stop here for a quick reality check. Electronically, RAM looks like a
spreadsheet, but real RAM is made of groups of semiconductor chips
soldered onto small cards that snap into your computer (see Figure 3-15). In
Chapter 4, you’ll see how these groups of chips actually make themselves
look like a spreadsheet. For now, don’t worry about real RAM and just stick
with the spreadsheet idea.