DolphinDOS 2 consists of a KERNAL ROM replacement for the computer and an add-on hardware for the disk drive. The disk-drive side hardware gives both the firmware ROM, replacing the original CBM V2.6 DOS and an eight KiB of RAM expansion accessible at $8000. This additional RAM is used generally as a track buffer during disk operations. For fast data transfers DolphinDOS 2 taps on the unused 6522 VIA port to allow SpeedDOS compatible parallel connection between the drive and the USER PORT of the computer. This combination of RAM, parallel transfer and much faster GCR decoding routines was what made DolphinDOS one of the fastest drive “speeders” on the market and a true hit. It was not only “wahnsinnig schnell” but also virtually bug free from the very beginning! While designing the hardware was a relatively simple task, writing this kind of complex software and making it so well done at first try is something we didn’t see often, even in the golden days of computing age... It was also certainly not the case with some of the competing products. Not only the firmware but also the supplied utility programs were highly useful, easy to use, well tested and practically bug free.

The complete set consists of the following elements:
  • KERNAL ROM replacement
  • DOS ROM replacement
  • RAM expansion
  • SpeedDOS type parallel connection

Computer side:

On the computer side you need your KERNAL ROM replaced with one that knows how to fly (or swim, was it?) fast. The easiest way to make a KERNAL replacement these days is to use EasyFlash cartridge (man, ‘skoe’ - the guy who created it - R0XX hard all the way!! Kudos Thomas!). It is the most convenient solution, which works perfectly well... unless you really need your EXPANSION port available for something else. IDE64 cartridge (Josef and ‘Soci’ rock too!! :-) is a fully valid example but 1541 Ultimate is IMHO nothing to be sniffed at either. In such case I believe it to be better to install a permanent KERNAL ROM replacement directly on the computer’s mainboard. There are many 24pin ROM -> 28pin EPROM adapters available. The one I use, I designed myself (with invaluable support from cbm-hackers community, especially Gerrit Heitsch).

Drive side:

The drive-side hardware is a relatively simple RAM/ROM expansion for a 6502. All of it can fit on a single, double-sided PCB, which connects to the main drive controller board through 6502 and 6522 sockets / soldering pads. Since (unlike in version 3, which uses its own PIA chip) there is nothing really special here, a generic/universal 6502 expansion board, like e. g. The universal 6502 RAM/ROM Expansion designed by Nicolas Welte, can be successfully used to build a working DolphinDOS 2 clone (parallel connection to the VIA port has to be done separately then, the same like in case of the little known and very rare DolphinDOS 1). In any case, I wanted to revive a complete, dedicated DolphinDOS device. In 2002 I reversed the fish and built a proof-of-concept prototype. The board was an autorouter type of mess but I wanted a quick check of the schematic to see if it needs any debugging. Luckily there was only one problem (a missing connection), which could be easily fixed with a fly-wire between two vias, and the thing worked otherwise very well. Having that confirmed, I went on to improving the layout and that was when I experienced a harddrive crash, which ate most of my files related to this project. It took me some good years before I came back to the subject and did things better. Results you can find on the sub-pages here.

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