Origin of "partition" in storage devices

Many/most? early drives were CAV (Constant Angeular Velocity) with the same amount of data on each track. Therefore, the data transfer rate, once on the right track, was the same. BUT, the bits were physically closer to each other on the inner (higher numbered) tracks, and the error rate was sometimes noticeably higher on the inner tracks. (and hence TG43 on 8"drives) That was why most OS's would allocate space starting at the outside (lower numbered) tracks, and only use the innermost tracks when necessary. With no errors, inner and outer tracks were the same speed. BUT, if you count RETRY's on a less than a perfect disk, then outer tracks had faster access than inner tracks. In addition, track to track step times were conservative, often without knowing what step rate the drive could do, to allow plenty of time for completion and settling. In fact, one of the changes from PC-DOS 2.00 to PC-DOS 2.10 was to slow the step rate, because the Qumetrak 142 drives in the Convertible and PCJr were much slower. Some floppy drives could do a "Recalibrate" (seek to track 0) much faster, and use a track 0 sensor to know when it had arrived. Many OS's, when they encountered a "SEEK ERROR" (reading the track shows a different track number than desired), would RECALIBRATE and then step by step seek back to the desired track, rather than calculating how many tracks they were off. Because of that, access time to get to the desired track was sometimes faster for the outer (lower numbered) tracks, due to detours to track 0. Since the DIRectory gets accessed more than any other location, access time to the DIRectory track is especially important. Some OS's, including Microsoft Stand-Alone BASIC, COCO, etc. put the DIRectory at the seek center. So long as there were no "SEEK ERROR"s, that was faster, but when there WERE "SEEK ERROR"s, putting the DIRectory on track 0 (such as MS-DOS and Mac) was faster.