Apple opened shop on April 1, 1976 as Apple Computer, Inc. and despite some rocky times, is still going strong 33 years later.

The Cupertino-based company started life with the Apple I computer, which was built by hand by co-founder Steve Wozniak. The Apple II was introduced in 1977, kick starting the personal computer market.

The Apple II posrted innovations not seen on other computers of the time -- like a floppy disk drive instead of cassette tapes for data storage, and color graphics support. While the computer originally shipped with a cassette drive, the move to a 5.25-inch floppy drive helped Apple maintain its lead over competitors that were trying to gain a foot hold in the personal computer market.

The Apple II went on to become the most popular personal computer of its time.

Apple gave the world a taste of what was to come when it released the Lisa computer in 1983. It offered the first graphic user interface and used a mouse for navigation. The Lisa stumbled and failed to gain market share because of its prohibitively high price tag.

While the company's first attempt at a graphic user interface-based computer flopped, it's second try -- the Macintosh -- hit gold and revolutionized the computer industry much like the Apple II did. Apple released the Macintosh in 1984.

The Macintosh also changed the face of the graphic design and publishing industry. The Mac, combined with PageMaker from Aldus and the LaserWriter with Adobe's PostScript technology, started the digital desktop design industry that later led to the rise of QuarkXPress, Adobe Photoshop, and now Adobe InDesign.

For a time, it seemed Apple could do no wrong, but following Steve Jobs's forced departure from the company in 1985, it eventually began to lose focus and market share. The company split the Macintosh line into a series of confusing configurations that included the LC, Quadra, Centris, Performa and PowerBook lines.

The company was also struggling to make its Newton MessagePad -- the first PDA on the market -- a success, but early handwriting recognition issues and a high price kept most consumers away.

Apple continued to flounder in the market and bleed customers to Microsoft's Windows platform while running through a series of CEOs in hopes of finding someone that could get the company back on track. Apple found that person in 1997 when Steve Jobs was welcomed back to the company as interim CEO.

Mr. Jobs began slashing away at the muddled product lines and introduced the all-in-one iMac in 1998. The iMac was the first computer to sport USB, and it also dropped the floppy drive found on every other computer on the market. Apple eventually phased out the floppy drive on all of its computers, and replaced the ADB, serial and SCSI ports with USB and FireWire ports.

Along with changing the standard ports on its computers, Apple also managed to pull off a full hardware platform switch -- not once, but twice. The company first migrated from the 680x0 processors it had been using since the Mac's launch to PowerPC architecture, and then again with the switch to Intel chips. The company also made a bold move when it shelved it Mac OS it had been shipping with all of its computers and began shipping a brand new Unix-based operating system: Mac OS X.

Apple wasn't content to stick to the computer market, so in 2001 the company unveiled the iPod portable digital music player. Despite initial concerns over the price, the iPod became a runaway success and changed the digital media player market much in the same way the Apple II and Macintosh changed the computer market.

The iPod line has since grown to include the iPod classic, iPod nano, iPod shuffle and iPod touch. Apple moved beyond computers and media players when it introduced the iPhone in 2007. The iPhone has since gone on to change how users view smartphones and is a popular seller in countries around the world.

Despite some missteps -- like the Mac Cube, MessagePad, Lisa and hockey puck mouse -- Apple has been a leader in innovation in the computer industry for 33 years. Other companies have tried to mimic Apple's ability to design useful products that look good, too, but so far most competitors are still imitating and leaving the innovation to Apple.