In 2011, the term "portable computer" conjures up images of sleek tablets, pocket-sized smartphones, and ultra-light laptops. But 30 years ago, the Osborne 1 made its debut as the world's first portable PC, and weighed nearly 24 pounds.

Created by Adam Osborne of Osborne Computer Corporation, the device was unveiled on April 3, 1981 at the West Coast Computer Faire at San Francisco's Brooks Hall. It had a 5-inch display sandwiched in between two floppy disc drives and it cost $1,795. Although 24 pounds sounds like a hefty size for a mobile gadget, Osborne 1 was meant to be portable. It had a rugged plastic case that folded up, complete with a handle, and a battery pack. Roughly the same size as a sewing machine, the device could fit underneath the seat of a commercial airliner.

Osborne 1 was clearly light years away from modern portable computers not just in terms of its size, but also its capabilities. It could only display 52 characters in one line, but the small screen size was part of the reason the computer could be mobile.

Consumers today probably wouldn't consider a gadget of that size a "mobile" device. By contrast, modern tablets make Osborne 1 look comically oversized. To put it into perspective, the iPad 2 measures 9.50 by 7.31 inches and even the heaviest model only weights 1.35 pounds, while the first iPad only weighs 1.5 pounds.

Osborne 1 might not have sold as well as the iPad, but it was still considered a success, with sales of about 10,000 units per month. In September 1981, it reached $1 million in sales.

By September of 1983, however, Osborne Computer Company filed for Chapter 11 bankruptcy protection. Technologizer notes that the mistakes made by the company are known as the "Osborne Effect," meaning it would announce new products before they were actually ready, causing customers to stop purchasing the devices that were available. Additionally, by the time Osborne filed for bankruptcy, consumers were leaning toward the IBM PC.