Double sided 8" floppy in SA800 drive

I assume that you also have the ability to perform a Low Level Format (LLF) of the diskettes which you want to use as "flippies". While the original side may have arrived with the correct LLF, even if the media was originally used as a DSDD media, when flipped, I doubt very much that there would be a usable LLF as a SSSD surface on the other side. Since you specifically mention a Shugart SA800, I assume that the controller and other hardware and software on your system has the ability to perform an LLF. For the PDP-11 systems which DEC manufactured, DEC explicitly omitted any possibility of performing an LLF on both the RX01 (SSSD) and RX02 (SSDD) drives. DEC always attempted to sell users DEC pre-formatted diskettes. Other manufactures of 8" floppy devices (some probably with Shugart drives) also included firmware on the controller which allowed the user to LLF any media as desired. In particular (the one drive which I used very extensively for many years about 20 years ago), the DSD 880/30, has a single RX01 / RX02 / RX03 drive which supports all four types of LLF on the media: SSSD, SSDD, DSSD and DSDD. NOTE that in all cases, the index hole for the first two examples of single sided media was close to the center line of the media. In the case of the double sided media, the index hole was about 1/2" further from the center line. In addition, while DEC software and hardware on the PDP-11 did have a command for the RX02 (SSDD) drive which used the characters "FORMAT" as the command name, the actual function of that command was definitely NOT an LLF. In order to be successful, the media HAD to already have an LLF. The "FORMAT" command was then able to change the media to SSSD from SSDD and visa versa. Media which were UnFormatted could NOT be used without first having an LLF via some other non-DEC hardware. In my experience, there is a bit of a problem with using both sides of a single sided media. While I agree that it was "done all of the time", I doubt that the percentage of the total was very high, perhaps 1% or even 2% of the time. As for the problem. it would only become a problem over time as the media was used AND accumulated dust in the jacket. When the media was flipped and the other side used, the rotation would be in the opposite direction and the dust would tend to be disturbed on the other side as it was nudged out of any locations where it had accumulated. This aspect would NOT be a problem with distribution media used as a "flippies" since the files would rarely be read, so the dust would not accumulate to the extent of becoming a problem. I remember that the manufacturer of the DSD 880/30 used a flippy (rather then two SSDD diskettes) to provide the user with the installation files. So YES!, but I recommend that only limited use be made of the media if both sides are going to be used. As for using SSDD media as DSDD media (and visa versa) and punching the extra pair of holes, there is an alternative!!!!!!!!! On my DSD 880/30, I installed a DPDT switch to flip the use of the index holes (each detector has its own electrical circuit). In the normal position of the DPDT switch, everything worked as expected. In the opposite position, all single sided media with the index hole close to the center line were (falsely) detected as double sided media. As a result, the single sided media could have an LLF done as DSDD and thereafter be used as double sided media. BUT, the extra index holes as DSDD were not required. Obviously, the reverse would have been true, but it seemed a waste to pay extra for double sided media with the index holes in a different position and use only a single side. By the way, after an LLF as DSDD media, the floppy could still be used as a SSDD media since, obviously, the LLF on the first side was identical to what the SSDD media received as its LLF. Also, I seem to remember that my attempts to LLF media which were originally SSDD into DSDD were successful over 99% of the time with all non-DEC 8" floppy media. (Surprisingly, when I attempted to perform an LLF on out of date DEC distribution 8" floppy media, a fair number could not support an LLF to the second side - although reverting back to an LLF as SSDD media was again almost always successful.) By the way, what system are you using the Shugart drive on? If it is a PDP-11, I might be able to offer additional information. If you have any other questions or I have not explained some items very well, please ask. I used the DSD 880/30 as my primary media with the RX03 as the backup for about five years until I could afford RD51 and RD52 drives. So I have a bit of experience. Jerome Fine