From: markm@vl.com.au   
      
   christianlott1@yahoo.com wrote:   
      
   > I select any of these models, I insert the disk, reset the machine and   
   > nothing happens (the screen is blank). The leftmost red light is on and   
   > the three blocks beside it are black.   
      
   Ah, the fun begins! ;)   
      
   The TRS-80 Models 3 & 4 booted DOS from diskette - there was no DOS in   
   ROM so you need a bootable disk. It may be that the DSK images you have   
   tried aren't bootable!?! Or perhaps they're Model I boot disks?   
      
   Now, to complicate matters, there were more than a few different   
   operating systems available, perhaps most notably TRS-80, Newdos/80 and   
   LDOS. The degree of interoperability between DOS formats differed from   
   DOS to DOS.   
      
   To further complicate matters, the TRS-80 models supported different   
   disk formats such as single and double density (with different adapters   
   no less), numbers of tracks, as well as other options. In most cases,   
   you needed to explicitly specify what format of disk you were using.   
      
   If that's not enough, some of the DOSes also had 'Model I' counterparts   
   which had slightly different formats again. You could play 99% of Model   
   I (non-bootable) software directly on a Model 3/4 if you set up the DOS   
   correctly.   
      
   Then you have 'native' Model 4 mode, which brings another set of DOSes   
   and hardware compatibility issues to the table. However, in this case   
   you shouldn't need to worry about this.   
      
   > The .DSK in question is a basic game called Temple of Apshai. I've   
   > tried other .DSK images with the same result.   
      
   I suspect TOA is in fact bootable - perhaps it's a Model I? The Model I   
   DOSes won't boot on a model 3/4 and vice-versa because of hardware   
   differences.   
      
   As for other non-bootable DSK images, you need to know what format they   
   are, and boot the corresponding DOS boot disk. You may also need to   
   specify - within that DOS - the exact format of the DSK image. As I   
   said, some DOSes are smarter than others and can work this out to some   
   degree itself. Others would know more about this than me.   
      
   > Also, I has some standalone trs80 basic files I may wish to try. How do   
   > I load these?   
      
   You'll need to boot a DOS diskette and run DOS basic. If the files you   
   have are on PC format you'll have to import them onto a compatible DOS   
   data disk to run them in the emulator. xtrs (linux) will allow you   
   import a file directly from the host OS. It does also run under cygwin   
   so in theory it would work on windoze too.   
      
   Regards,   
      
   --   
   Mark McDougall, Engineer   
   Virtual Logic Pty Ltd,    
   21-25 King St, Rockdale, 2216   
   Ph: +612-9599-3255 Fax: +612-9599-3266   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)