Deciphering an odd floppy disk format.

Den tis 16 feb. 2021 kl 03:16 skrev Fred Cisin via cctalk < cctalk at classiccmp.org>: I have seen them, except for that one. Quite a rambling story. I only managed to read parts of it. Unfortunately there was little detail of what he did, except that he did everything. A bit interesting to compare the Q1 Story with the one provided by Daniel Alroy. The disk controller probably had some intelligence in itself. It seems to have been connected over sync serial links to the computers. Probably it provided a quite high level interface to the computer. When I analyzed the tracks further I found that track 0 had 40 bytes sectors. Then there were tracks that had 80 character sectors. These were mostly text data on these tracks. A few tracks had sectors with 256 bytes. They seemed to contain binary data. I assume track 0 contains the directory that tells what files go where and the sector size on that track. Supposedly the intelligent floppy controller (more like a file server) knows of the directory structure and file structure of the various types of files there are. In a sense this type of 80 characters record fits very well with classic punch cards. Perhaps data entry was a big application? This type of early distributed systems look a bit like the Cogar 4 / Singer/ICL 1500 systems or Incoterm SPD 10/20. Intelligent terminals with local storage connected to a central storage (file server).