First post, by spark2k06
I share a variant of the SMBacker RTC design (http://www.smbaker.com/8-bit-isa-diskonchip-rtc-board):
Gerbers availables on OSHPark: https://oshpark.com/shared_projects/9vuRscy3
This design consists of a very low profile ISA card, which has the port 70h mapped as fixed. Soon Sergey's Micro8088 project will have support for it.