well, you probably all know by now that my favorite fiction writer is J.R.R. Tolkien (check the sig, for example).
a few quotes from my well-worn, red-covered single-volume Collector's Edition of The Lord of The Rings (Houghton Mifflin Co.).
Ancalagon
The Fellowship of the Ring, Book I, Chapter 2, page 70.
(this is just after Gandalf throws The Ring into Frodo's fireplace and Frodo takes it out).
'Your small fire, of course, would not melt even ordinary gold. This Ring has already passed through it unscathed, and even unheated. But there is no smith's forge in this Shire that could change it at all. Not even the anvils and furnaces of the Dwarves could do that. It has been said that dragon-fire could melt and consume the Rings of Power, but there is not now any dragon left on earth in which the old fire is hot enough; nor was there ever any dragon, not even Ancalagon the Black, who could have harmed the One Ring, the Ruling Ring, for that was made by Sauron himself.
Scatha(sorry, i don't know how to enter accented characters)
Appendix A Annals of the Kings and Rulers, II The House of Eorl, page 345.
'Many lords and warriors, and many fair and valiant women, are named in the songs of Rohan that still remember the North. Frumgar, they say, was the name of the chieftain who led his people to Eotheod. Of his son, Fram, they tell that he slew Scatha, the great dragon of Ered Mithrin, and the land had peace from the long-worms afterwards. Thus Fram won great wealth, but was at feud with the Dwarves, who claimed the hoard of Scatha. Fram would not yield them a penny, and sent to them instead the teeth of Scatha made into a necklace, saying: "Jewels such as these you will not match in your treasuries, for they are hard to come by." Some say the Dwarves slew Fram for this insult. There was no great love between Eotheod and the Dwarves.
here's some more about Anacalagon (clarifying Gandlaf's quote in chapter 2 of Fellowship of the Ring)
this is taken from Tolkie's great work, The Silmarillion, published posthumously.
The Silmarillion, Quenta Silmarillion, Chap. XXIV Of the Voyage of Earendil and the War of Wrath. page 252.
But Earendil came, shining with white flame, and about Vingilot were gathered all the great birds of heaven and Thorondor was their captain, and there was battle in the air all day and through a dark night of doubt. Before the rising of the sun Earendil slew Ancalagon the Black, the mightiest of the dragon-host, and cast him from the sky; and he fell upon the towers of Thangorodrim, and they were broken in his ruin. Then the sun rose, and the host of the Valar prevailed, and well-nigh all the dragons were destroyed; and all the pits of Morgoth were broken and unroofed, and the might of the Valar descended into the deeps of the earth. There Morgoth stood at last at bay, and yet unvaliant. He fled into the deepest of his mines, and sued for peace and pardon; but his feet were hewn from under him, and he was hurled upon his face...
this bit describes the very last part of the great War of the Silmarils.
AFAIK, these two are the only named dragons in Tolkien's work - The Hobbit; The Lord of The Rings and The Silmarillion, apart from Smaug of course.
but to name a computer "Smaug" would be a little too prosaic for my taste, there are probably about 1,000,000 computers named Smaug around theh world...