SD - Arduino Sketches: Tools and Techniques for Programming Wizardry - page 208

The hardware needed to run the examples in this chapter includes:

Arduino Uno

■

Ethernet shield (Arduino, SainSmart, or similar board)

■

Micro-SD Card

■

You can i nd the code download for this chapter at http://www.wiley.com/
go/arduinosketches on the Download Code tab. The code is in the Chapter 12
download folder and the i lename is Chapter12.ino .

Introduction

The hunger for storage has increased exponentially. Early computers did not
have hard drives; the operating system and applications were stored on a l oppy
disk. The i rst commercially available l oppy disk was an 8-inch disk, which
became available in 1971. It could store an enormous 175 KB of data. In 1976, the
standard became 5 ¼ inch (ironically known as the minil oppy). The original
model could store 87.5 KB, but newer models could store more than 1 megabyte.
The large slots on your desktop computer that house a DVD drive or Blu-ray
drive are that size because of l oppy disks; the size of the minil oppy disk drive
became standard.
As technology advanced, so did the storage capacity of disks, and 5 ¼-inch
disks were considered too big; the computer industry turned to 3 ½-inch l op-
pies, known as micro-l oppies. Early models could store 360 KB, but later models
could either be single density (720 KB) or double density (1.44 MB). Those are
the disks that powered the computer industry, storing and exchanging data.
Operating systems were sold on l oppies, and the i rst thing that users were
told to do was to copy this l oppy and keep the original safe. A single l oppy
disk was more than enough to hold an operating system and a few programs.
Figure 12-1 shows examples of three different types of early l oppy disks.

Figure 12-1: Floppy disks