Marc,
On Sunday, October 8, 2017 at 11:48, CuriousMarc wrote:
> Thanks, I wasn't aware of this subtlety.
You're welcome.
> But this is for the 7970E only, right?
Right.
> Can you boot a 21MX from a 7970B tape with the standard boot ROM?
Yes.
The boot ROM data transfer loop is just a tiny bit too slow -- 14.26 usec
worst case (i.e., with an intervening RAM refresh) -- for the 1600 bpi
interface, which allows 13.9 usec before indicating a Timing Error. The
800 bpi interface allows double that time, which the ROM loop easily meets.
-- Dave
