![]() I support DMK in my MSX emulator, and bear in mind that it's a bit of a confused file format. But it can't be very analog because the DMK files are still all the same size. I found a tool for viewing DMK files that helped me realize a few more of my DMKs have this little directory track declaration, but their offsets occur at locations varying by a number of bytes from the start of the disk image. ![]() Because the actual sector data starts at offset 0x0108 of the DMK file, which leaves 120 bytes between the IDAM table and the sector data, which must be internal/low-level "raw" data. The IDAMĪnd sector data each have CRCs, this is just like on a real disk. Have bits 6 or 7 set of byte 4 of the disk header then each singleĭensity data byte is written twice, this includes IDAMs and CRCs (theĬRCs are calculated as if only 1 byte was written however). The actual track data follows the header and can be viewed with a hexĮditor showing the raw data on the track. The two high bits of an offset are flags. Then there is the first 128-byte track header section containing a list of 16-bit "offsets" to each "IDAM" in the track. The format starts with a 16-byte header that describes the disk geometry. The DMK format seems to be a bit vague to me probably due to assuming a relatively deep level of knowledge about how the disk format and drive controller work at a low level. So far I'm only digging into the TRS-80 Model I/III side of things. It's capable of representing copy-protected disks and all "WD-1771 and WD-19xx controller functions and formats". The New York Times reports on the new double-sided disk map.DMK is a low-level disk image file format used by TRS-80 Model I & Model III, Tandy Color Computer, Dragon 32 & 64, and MSX emulators. So, the new double-sided disk map is a welcome development in the history of cartography. Claes Jansz Visscher, Nova totius terrarum orbis geographica ac hydrographica tabula (Amsterdam, 1652).Īlthough competing cartographic solutions to mapping the world have challenged the prominence of Mercator’s world map, his projection is still used in many academic works and news publications today. ![]() This map by Claes Jansz Visscher shows how elaborate such prestige world maps became by the mid-seventeenth century. The Mercator projection also became very popular for prestige world maps that showcased empires, kingdoms, and cultures around the world. Gerardus Mercator, Nova et Aucta Orbis Terrae Descriptio ad Usum Navigantium Emendate Accommodata (1569). ![]() Mercator’s projection relies on straight rhumb lines and perpendicular intersections of parallels and meridians, making it practical for maritime navigation. This world map presents a perspective of the globe that is radically different from the classic Mercator projection, which was developed by geographer and cartographer Gerardus Mercator in 1569. Richard Gott, Robert Vanderbei and David Goldberg, Double-sided disk world map, New York Times. But then along comes an innovator,” according to The New York Times. Richard Gott, an astrophysicist at Princeton who had previously mapped the entire universe. Like sports, the mapmaking game can sometimes grow stale when top competitors are stuck on the same old strategy, said J. ![]() “Enter a brash new world map vying for global domination. And the Dymaxion map, hyped by the architect Buckminster Fuller, debuted in a 1943 issue of Life.” The Winkel Tripel, the map style favored by National Geographic, dates to 1921. The Mercator was devised by a Flemish cartographer in 1569. The New York Times reports that “Most of the world maps you’ve seen in your life are past their prime. Major innovations in the history of cartography are difficult to achieve, despite new digital tools such as Geographic Information System (GIS) mapping. This map is a two-dimensional double-sided disk centered on the earth’s poles. A new world map may transform the way we look at the earth. ![]()
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