"While it is unlikely that the 7110 can be seriously damaged....." - Intel

A project log for Magnetic Bubble Memory Makes a Comeback

An Old Attraction to Magnetic Bubble Memory leads to a 1Mbit Board for the SBC-85, 8085 based single board computer

craigCraig 04/10/2020 at 20:170 Comments

More reassuring words have never been spoken.  To quote the Intel Application Note AP-119

"While it is unlikely that the 7110 can be seriously damaged, it is possible for the seeds and bootloop ... to be lost."

Since I can re-seed and re-enter the bootloop if necessary, given this morale booster (and after thoroughly checking all of the waveforms driving the 7110) I went ahead and populated the bubble chip itself.  Right out of the gate I did a register configuration, then abort with the "9" command and a read of the bootloop using the "B" command.  Then saved the 7220 FIFO to the SBC-85 RAM and dumped ....

... then anxiously compared the dump to the bootloop printed on the device.

Whoop Whoop Whoop.

What we have here is a very, very, very good step.  

Obviously at this point I am still manually hacking my way through all of the commands in pretty raw form.  Now back to writing more software so it is easier to read and write to the bubble.

Once the next level of software is written, I will be able to read and write to the bubble itself.  The first check is to make sure the seed bubble is OK, but since the bootloop was intact there is no reason to suspect that this module needs to be reseeded.