The Spectrum-Amiga Network


Please note this content is from the original WoS site, and may no longer be relevant. If you have any queries, please contact us.

SlingNET originally started out as a means to get a mass storage device for the ZX-Spectrum. It connects to the parallel port of an OPUS Discovery. Soon after it, it became the means to get games and other software available for use with the Spectrum Emulator for the Amiga. This made a lot of sense, as the author, Jeroen J Kwast was my roommate by that time. Later on, I used it to create TAP files to be used by the PC emulator Z80. I was able to upload all my software that way. I wrote several tools to create and maintain these TAP files, which you can download below. Later on, I moved entire floppy images from the Spectrum to the Amiga, which I decoded there. This way, it would take only about 3 minutes to upload an entire 800Kb floppy.

That’s right, I managed to push 800Kb on 1 OPUS floppy. I had to buy a decent floppy drive and rewrite the OPUS ROM, but it worked perfectly.
For the curious people, I also have The Complete Opus Discovery ShadowROM v2.2 Disassembly available here (or in WordPerfect 6.0/6.1 format here )


Nothing special is needed for the Amiga side. As for the Spectrum, you will need the following:

  • The OPUS Discovery floppy system,
  • OPUS ROM version 2.2 or 2.3 (either 48K or 128K Spectrum version)
  • OPUS optional 2Kb RAM chip (4116)

And of course a parallel cable with the following (straight) pinout:

          Amiga       Spectrum      Does

           D0 -------- D0     --\
           D1 -------- D1       |
           D2 -------- D2       +-- Nibble to handle
           D3 -------- D3     --/
           D4 -------- D4     ----- Spectrum toggle-bit
           D5 -------- D5     ----- Amiga toggle-bit
           D6 -------- D6     ----- Spectrum error-bit
           D7 -------- D7     ----- Amiga error-bit
         BUSY -------- ACK    ----- Server-wait-bit


You also need the SlingNET network operating system. This consists of the server side (Amiga) and client side (Spectrum). It can be downloaded below.

  • The Spectrum side
    The Spectrum part patches the OPUS ROM through the extra 2Kb RAM, where the operating system tables are shadowed by the OPUS ROM. The syntax is quite easy and looks a lot like the OPUS itself or the microdrive.

    • First of all, you will have to connect to the server. This is done with the command:FORMAT "n";1
    • Loading/Saving/Verifying/Merging a file is done with:LOAD *"n";1;"[name]" [paramaters]
      SAVE *"n";1;"[name]" [parameters]
      VERIFY *"n";1;"[name]" [parameters]
      MERGE *"n";1;"[name]" [parameters]The part from [name] on is the same as with tapes, so you can use LINECODESCREEN$ or DATA.
    • Deleting a file uses the syntax:ERASE "n";1;"[name]"Note that there is no asterisk after the command and no parameters after the filename.
    • You can not use the CAT command, as it is not implemented and it will reset your Spectrum!
  • The Amiga side just has to be started from either the Workbench or the CLI. You can press F10 to shutdown the server. All saved files will be in the directory DH0:ZXNet/. In order to use them in Jeroen’s emulator you will have to either copy them to the Progs subdirectory of the emulator or recompile the source after changing it in there.


  • Download the Spectrum part of SlingNET
  • Download the Amiga part of SlingNET
  • Download the utility to convert programs for Jeroen’s emulator to the PC’s .TAP format (Z80)
  • Download the utility to view the contents of a PC .TAP file
  • View the source of the Spectrum part of SlingNET
  • View the source of the Amiga part of SlingNET