Apple Tablet: computer giant's hits and misses
With Apple announcing record £2 billion profits in the last quarter and excitement surrounding Wednesday's new product announcement reaching fever pitch, it is hard to imagine the US computer giant failing.
No pictures of the Apple tablet have been leaked, so gadget fans are having to make do with high-tech mock-ups Photo: Gizmodo
But here is a look back at some of Apple's previous product launches, some of which did not hit the mark. 
:: Introduced in 1977, the Apple II was one of the first successful mass-produced personal computers. Selling more than five million units throughout its long production run, the Apple II is often credited as the machine which made Apple a commercial success. In 1989 the Macintosh Portable was Apple's first laptop. Featuring 1MB of RAM, a black and white LCD screen and full keyboard, the machine opened up the reality of business on the move. Unfortunately its lead acid batteries were so heavy the Macintosh Portable tipped the scales at more than 7kg.
:: The Macintosh LC (standing for low cost) was an affordable computer designed for the home and schools. Launched in 1990, the colour-capable machine won over consumers with its affordability, simple design and ease of use.
:: Released in the early 1990s the Newton MessagePad shared many of the design principles of today's tablet PCs. This personal digital assistant is still regarded by its loyal fans as the grandfather of the iPhone. However, consumers complained that its handwriting recognition system was unreliable and a high price tag ultimately sealed its fate. It was discontinued in 1998.
:: In 1995 Apple attempted to grab a slice of the lucrative console gaming market with its Pippin, boasting multiplayer modem gaming and a CD-ROM drive. But the Pippin's timing was poor – it arrived just after Sony's PlayStation – and in the end fewer than 50,000 were sold, while Sony sold more than 102 million units.
:: The colourful iMac – available in a rainbow of translucent plastic – captured consumers' imaginations in 1998. The original "Bondi blue" iMac became a design classic and Apple's marketing began to show its product as the fun alternative to the predominantly grey PCs of the time.
:: Cyberdog was Apple's solution to Internet Explorer. The sophisticated web browser featured email, news readers and drag-and-drop FTP. But in 1997, Apple abandoned the software and Internet Explorer became its default browser until the arrival of Safari in 2003.
:: In 2001 Apple launched the iPod. The portable media player rocketed Apple to its position today as one of the world's most important consumer electronics manufacturers. With more than 220 million sales and counting – including 21 million in the last quarter alone – the iPod in its many guises continues to dominate the market.
:: After the sales phenomenon of the iPod, the iPhone took the baton in 2007. Reinventing the mobile phone, Apple combined a music and video player, a camera, an internet browser and created the profitable market for downloadable apps. In the last quarter Apple sold 8.7 million iPhones, representing a 100% growth over the same period last year.
:: What next for Apple? At 6pm (GMT) today Apple will hold a press conference from its base in San Francisco, California, where it is expected to showcase its new iTablet computer – rumoured to be a slate-shaped touch-screen device with the power of a laptop combined with the portability of a smartphone. Apple's CEO Steve Jobs said: "The new products we are planning to release this year are very strong, starting this week with a major new product that we're really excited about."