The early indications have been that the Mac mini is a hit. In addition to Piper Jaffray's survey, Apple's online store and other online vendors have been showing a backlog in orders since before the Mac mini became available last month. Apple's online store, for instance, currently gives customers an estimated ship date of three to four weeks after they order. Apple's Web store is showing a similar backlog for its two iPod Shuffle models. With a price starting at $99, the iPod Shuffle represents Apple's attempt to boost its share of the lower end of the digital music-player market. Despite the low price, some analysts had questioned how popular the device would be due to its design compromises. The Shuffle doesn't include any kind of screen, making it difficult to select songs directly with the device. The dearth of supply for the Mac mini and iPod Shuffle is only the latest time Apple has had trouble meeting demand for its products. Last fall, the company had a backlog of orders for its iPods and some of its computers based on the PowerPC G5 chip. Last year, the company struggled to meet demand for its iPod mini immediately after it released the device. In recent trading, Apple's stock was up 67 cents, or about 0.9%, to $77.57.