Minor ImageDisk update has been posted

On Thu, Mar 8, 2012 at 12:57 PM, Dave Dunfield <dave12 at dunfield.com> wrote: Ah yes, that does seem a better idea :) Not directly, but the size code in the format command determines the physical size written on the track for each sector, independent of the size values in the ID data. So you can create a format template from smaller sector sizes to position the sector headers, then write to the data fields of the real sectors to complete the track. In cases where the header size is larger than the template sector size, the extra headers will be overwritten by the data fields. The only control you have is the format size and gap3 value, but it's enough to achieve the mixed sector size combinations I've seen so far. One popular format is 5x1024 + 1x512, to squeeze a bit more on to a 250Kbps MFM track. For that you could use a template of 17x256 with gap3 around 48. Each 1K sector spans 3x256 sectors, plus the accumulated gaps, with the final sector spanning two. The ID header values for the dummy sectors aren't important, as long as they don't match one of the real sectors. Calculating the unit and gap sizes to use for a general case is a bit more work than normal, but I'd imagine you could have a fixed list for known formats (as is done for some gap values). In other words, this is an optional extension to the .IMD file That's good enough for me to include it -- thanks!