Terence Boldt has been a busy man lately with his fixes to the ProDOS ROM-Drive Card. He has created a version 3.0 or the card and is currently finalizing the firmware of it, with changes and fixes coming in the past few days.
The ProDOS ROM-Drive card is a solid state 1mb card for the Apple II series computer which studied the entire drive into an EPROM. This card will boot ProDOS and BASIC in a blazingly fast 1.5 seconds on your machine.
The current card is Terence’s effort to make the firmware of the card relocatable, meaning that the card could also be used on the Apple III.
If you want to make your own cards, the physical card can be ordered from PCBWay and according to his writeup on the card, “If you’re planning on designing you own card, I highly recommend reading “Interfacing & Digital Experiments with your Apple” by Charles J. Engelisher and Apple’s “Apple II Reference Manual” as well as “ProDOS Technical Reference Manual” if you want to build a drive. You also need an EPROM programmer, some chips and a prototyping board. My designs used simple logic gates to decode addresses but if you want to reduce chip count, you’ll also need a PAL/GAL logic programmer (which some EPROM programmers can do).”
The firmware and other related items are available from his Github page for the ProDOS ROM-Drive Project at: