Secondary Storage

There are two kinds of memory: A secondary storage device is any non-volatile storage medium not directly accessible to the processor. It includes flash memory, floppy disks, hard disks, optical disks, magnetic tapes, punch cards, and paper tapes. Programs and data stored in secondary storage must first be loaded into main memory before the processor can use them.

The 2X vs. 10Y Bytes Ambiguity
The ambiguity happens when memory sizes are discussed. For example, originally terabyte (TB) means 240 bytes, although communications and storage systems developers started using the term to mean 1012 bytes. This textbook resolves the ambiguity by adding a binary notation for all the common size terms. The last column shows how much larger the binary term is than its corresponding decimal term. These prefixes work for bits as well as bytes, so gigabit (Gb) is 109 bits while gibibits (Gib) is 230 bits.

Decimal term Abbreviation Value Binary term Abbreviation Value % Larger
kilobyte KB 10001 kibibyte KiB 210 2%
megabyte MB 10002 mebibyte MiB 220 5%
gigabyte GB 10003 gibibyte GiB 230 7%
terabyte TB 10004 tebibyte TiB 240 10%
petabyte PB 10005 pebibyte PiB 250 13%
exabyte EB 10006 exbibyte EiB 260 15%
zettabyte ZB 10007 zebibyte ZiB 270 18%
yottabyte YB 10008 yobibyte YiB 280 21%
ronnabyte RB 10009 robibyte RiB 290 24%
queccabyte QB 100010 quebibyte QiB 2100 27%




      I have a stepladder because my real ladder left when I was just a kid.