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GE Soft Eagle resurrection attempt

Posted: Sat Jan 06, 2018 11:44 am
by Administrator
Over the last two years I collected some parts of the ghostly GE Soft Eagle TT clone computer.
Unfortunately there is not much known about the system at all.
The concept was to design a computer that mimics most TT features, is mostly software compatible to the TT, could be expanded by add-on cards like a i80x86 PC. The mainboard was layout to fit in an AT style PC housing with AT style PSU power connectors of the time. Good decision I think. The Eagle features eight so called EagleChannel slots. These are proprietary interfaces and seem to be close to the MC68030 bus with some extensions (e.g. the two page documentation talks about signals called VME1..VME7 and VMEIACK). Will have to investigate it IF my Eagle may fly again one day.
In two points the layout differs from PC mainboard layout. You will neither find a CPU or FPU socket nor DRAM sockets/SIMM slots on it.
These are located on two add-on cards. One card holds the CPU (PGA socket) and the socketed FPU. The CPU/FPU card layout allows to either populate a PGA socket for the FPU or the PLCC version. Nice.
DRAM memory is located on a separate add-on card: five (!) banks with four 30pin SIMM slots each. A lot of capacity on the address and /RAS, /CAS lines to drive!
According to the interviews with GE Soft main developer Gero Ansch├╝tz published in the German ST Computer magazine they planned to put the memory on the mainboard with up to 16MB ST-RAM and up to 256MB TT-RAM. Probably only 10MB ST-RAM would be usable like in the TT due to the memory space occupied by the VME slot starting at $A00000. So it it not known if the memory add-on card can make use of 16MB SIMMs. As these are rare items - probably more rare then hens teeth - I would be happy to just use 4MB SIMMs.
This brings us to the last add-on card available: the EagleChannel-to-VME interface card. This probably will interface the system to existing VME cards - mostly graphic cards. But the VME interface card uses a backplane to triple the amount of available VME slots to be populated. Side note: most cards and their software drivers will assume that they are the only VME card and will probably assume they all start at $A00000. Well, who wants to throw the first stone at the developers for that?
As the GAL sources and driver sources for the Nova graphic cards are still maintained by atari-forum.com user Idek Tramielski I do have some hope to move the Nova's address space away from $A00000.
So folks, that's it for the moment. I will post more information and pictures at some point later.