franka2 wrote:whats needed now is info which 128KByte eprom fits into those cheapo rtl8139 NIC sockets subsequently to be copied into AMD64 adress space as MENUET64 execute-from-store assembler operating system...
The 8139 is probably the most cloned NIC in the world.
The design of the ethernet controller chip accomodates ROMs up to 128kB which require a 32 pin socket. Some OEMs however use a 28 pin socket because that can hold a 27C512 which can hold up to 64kB of code, more than enough for most cases.
Also recent versions of the controller have the capability of programming EEPROMs in situ. EEPROMs also require a 32 pin socket. But this programming capability isn't always implemented by OEMs? because it requires extra circuitry external to the controller and therefore extra cost (a significant fraction of the $5 price).
you have a 28 pin socket: Therefore you need a 27C series EPROM. And an external EPROM programmer (20ß0€). If you had a 32 pin socket, the 27C010 would also be feasible in addition to the 27C256 and 27C512. The 28 pin ROMs then sit in the socket with the bottom edge aligned (2 empty rows on top, the notch end).
he..he..he.. , have you read this Low cost embedded x86 teaching tool or perhaps you like a PDF version here.
Have a nice day