After attending to a few other tasks and discussions, we began archiving packs in late morning. Each had to be opened, cleaned, inspected and closed. It was then spun in the drive while the FPGA based tool extracted the disk image to its on-board memory. A utility transferred the on-board memory up to a PC over USB, where a Python program transformed the data into the Simh format for disk images.
We had 27 remaining cartridges on hand when we began; all the others have been processed already except for a small number that were previously damaged and unreadable. By the late afternoon we had 25 good images extracted and tested.
One of the packs had a divot dug into the disk surface which we expected would cause a crash; it was spun up last and did indeed crash the disk heads as they ran over the damaged area. The other pack that wasn't archived, an unmarked cartridge that had been sitting on display in the lobby of PARC, did not contain an Alto formatted data stream. It might have been used on a different computer system such as a DG Nova, but more likely it was just a virgin blank pack.
These images, as with the ones recovered in past weeks, were transferred to the software historians at Computer History Museum. We will be returning the physical cartridges to PARC, who we believe will transfer them in toto to CHM as artifacts for the museum collection.
RETRIEVING HISTORICAL 360 ERA TAPE DATA
A retiring employee from IBM Research, Jim Wyllie, found some tape reels in his office, simply marked '360'. Marc mounted them on his 9 track tape drives and extracted the data on these. Among other files, the complete source code to a mainframe based game called Space Conquest was recovered.