| Jeff Abrahamson on 1 Aug 2004 15:08:03 -0000 |
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On Sun, Aug 01, 2004 at 01:13:52AM -0400, Stephen Gran wrote: > [37 lines, 355 words, 2051 characters] Top characters: -teanior > > On Sat, Jul 31, 2004 at 09:44:46PM -0400, Jeff Abrahamson said: > > In fact, HFS and its variants store a 32 bit word representing the > > creator and a 32 bit word representing the type. The type is used by > > applications offering to open files to filter according to types they > > understand. The creator code determines the icon that the Finder uses > > to represent the file. > > That is a much clearer understanding of it than I ever had, but yes, > that is what I was struggling to say. The functional equivalent of > *nix's magic in the beginning of a file, but apparently a very different > implementation, roughly - is that about right? Yes, that's about right. But, where unix magic numbers are implemented only sporadically, HFS file and creator types are much more reliable, so the OS depends on them much more. > -------------------------------------------------------------------------- > | Stephen Gran | The only certainty is that nothing is | > | steve@lobefin.net | certain. -- Pliny the Elder | > | http://www.lobefin.net/~steve | | > -------------------------------------------------------------------------- What follows is totally off the subject, but I reserve the right to reply to signatures on occasion. ;-) Pliny the Elder was a Roman scientist and military commander who died from smoke inhalation while saving people from the eruption of Mount Vesuvius that buried Pompeii and Herculaneum. (Being a military commander, he had a small fleet at his disposal at the time.) So this quote of his, presumably from a time before that 24 August 79 A.D. eruption, is quite apt. Volcanic eruptions are broadly classified into four types, of which the most mild is called Hawaiian (after the volcanoes of Hawaii, of which only Pu'u O'o is currently active), then Strombolian, Vulcanic, then finally Plinian. It's interesting to note that three of the four names come from Italian volcanoes. The reason for this can easily be seen here, along with some rudimentary knowledge of the evolution of Western civilization: http://www.harcourtschool.com/activity/pompeii/pmpWhy.html In a Plinian eruption the quantity of gas released is so great that it cores out the magma column, producing a column of ash and gas above the volcano. This occurred during the 1906 eruption of Vesuvius, during which a column of ash rose six miles above the volcano for a period of twenty hours, boring an open cylindrical throat 1500 feet across. Although copius lava flowed down the mountain, the mass of gas released is estimated to have been greater than the mass of the lava. While checking that I had the right name with Herculaneum, I found a nice animation of what the 79 A.D. eruption of Vesuvius probably looked like: http://www.harcourtschool.com/activity/pompeii/pmpErup.html -- Jeff Jeff Abrahamson <http://www.purple.com/jeff/> 215/837-2287 GPG fingerprint: 1A1A BA95 D082 A558 A276 63C6 16BF 8C4C 0D1D AE4B A cool book of games, highly worth checking out: http://www.amazon.com/exec/obidos/ASIN/1931686963/purple-20 Attachment:
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