From: jegali70@gmail.com   
      
   On Monday, February 20, 2023 at 3:21:14 PM UTC+1, David Schmidt wrote:   
   > On 2/20/23 1:52 AM, Jens Gaulke wrote:    
   > > Hi there,    
   > >    
   > > I'm writing an Apple II Emulator.   
   > > [...]   
   > > Where I am stuck is: How do I get a "disk image" in my emulation? Which   
   format must it have? Woz? DSK? Up to know I know "that these formats exist".   
   How can I deal with these formats? What do I have to consider?   
   > I would start with what your goals are and work backwards from that.    
   > The Disk II is an analog device at is core, and has various layers of    
   > hardware, firmware, and software to decode the analog signal into a    
   > stream of bits. You can insert your emulation at any level along that    
   > spectrum, depending on the fidelity you are interested in achieving -    
   > which will dictate the ultimate capabilities of your disk emulation (and    
   > by extension, your emulator).    
   >    
   > At one extreme is the ".dsk" which is only the bytes that the operating    
   > system would ever present to a user; the data within all tracks and    
   > sectors. A layer beneath that is the nibble stream, represented by the    
   > decoded nibbles that are actually recorded on a disk; that affords you    
   > access to all the in-band data and enveloping headers and trailers. And    
   > beneath that is a ".woz" representation that defines lots more    
   > meta-information about the recorded signals and their environment which    
   > are important for encapsulating and decoding the many copy protection    
   > schemes that were devised using the Disk II. That level of information    
   > isn't available in any other encoding.    
   >    
   > The place to start getting a complete understanding of the physical Disk    
   > II ecosystem is Sather's seminal work, Understanding the Apple II (and    
   > Apple IIe) - chapter 9, "The Disk Controller". That's every detail at    
   > the bottom layer.    
   >    
   > Sather's books (and more) are available here:    
   > https://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Books/    
   >    
   > The Woz specification is available here:    
   > https://applesaucefdc.com/woz/reference2/   
      
   I have understood that so far, thank you for the explanation. What I have   
   problems with is "You can insert your emulation at any level along that   
   spectrum". I don't understand how I could write only one emulation for the dsk   
   format when my emulator gives    
   me one Disk II softswitch after another. Then don't I have to start at that   
   level and edit/implement the softswitches?   
      
   --- SoupGate-Win32 v1.05   
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