RSX has partitions; the term goes back at least as far as RSX-11/D. It may well go back to older versions such as RSX-15, but I haven't looked. OS/360 came in three flavors, PCP, MFT, and MVT. The OS/360 article describes MFT as having partitions selected at sysgen time (the acronym stands for "multiprogramming with a fixed number of tasks, with the concurrent tasks assigned across the available partitions). Both of these are memory partitions. The only OS I can think of predating the ones you mentioned is RT-11, the later versions (V2 did not have them). When did Unix first get partitions? paul

On 1/31/2022 11:01 AM, Tom Gardner via cctalk wrote: We had a local grown OS which was really a way to file paper tapes on a disk with file pointers.? We had an allocation method, all the file system things, a VTOC (copied a lot of ibm terms).? Eventually added half inch tape. This was on a Microdata 1621 minicomputer, and was named MPS, or Microdata Programming System.? We could take paper tape distributed software from Microdata, read them in and patch the terminal read / write and in the case of compilers, the paper tape read / write instructions and point them easily at our disk. Anyway our files had a name and? disk pointer which essentially was the cylinder and sector of the file.? All was on a 2.5 mb platter using both surfaces of our the removable pack on the 5mb Western Dynex drive. I added the capability to select surfaces which occurred when you booted the system and it would remember a surface system variable used by the disk routines that the programs didn't have to be concerned with. We could run from either platter this way with a copy of the system. Used the other platter for storing an image and doing a backup. Before that time, we had not written any way to back up, so I built that up. I later implemented a system to save out to tape, and rebuild and install to the disk. Also could later when I worked at Microdata use multiple drive and do the copying as well as double sized disks. There was a lot of odd data stored outside the disk space (allocated and free). I implemented a small rotating log of when the disks were booted, a name for the disk system running you could query, and other information. I don't know how this might fit into partitioning disks, but it did divide the two platter system into two separate file systems.? I never moved it to any hardware requiring more complication, but would have just added more indexing as to where the disk was mounted and what the volume was. You'll note that our 2.5mb file system isn't much larger than two 1.4mb 3 1/2" floppies, but we ran all the system software that we needed, system generation, sources and user files and easily had 20 to 25% of the space left over.? Much smaller systems back then. Single user similar to a large high wattage PC I suppose. The partitioning was implemented in 1972 (or dual platter backup). BTW we had an entertaining file recovery and sort that ran on either platter.? We'd erase the "other" platter to no files, and then copy all the files in on the other volume to the alternate.? When you finished all of your files were sequential and not wasted space. Our file system used linked sectors, and the free space was allocated by a linked list of sectors, not a bitmap.? The beginning of files were luckily odd enough that they could be recognized and another utility could recover all the files and rebuild the entire VTOC with nothing but the files present.? IMplemented over a couple of horrible days when the VTOC got erased. thanks Jim