The Virtual Sector Generator (VSG) sits between a 5.25" hard-sectored floppy controller and original drives to allow transparent and interchangeable use of soft or hard sectored media. The board is jumper selectable to work with 10 sector or 16 sector controllers. The board is powered by a standard 9 volt battery and automatically powers itself on and off with the host computer. A battery will last a year or more of typical use.
Since 16 sector media – and especially 10 sector media – is getting difficult to find, this is a great way to breathe new life into systems using controllers from North Star, Heathkit, Micropolis, Vector Graphic, and MITS/Altair.
The VSG passes all signals between the controller and the drives except for index/sector pulses. Pulses from the drives are received by the VSG and the VSG generates the index/sector pulses that are seen by the controller. This arrangement is required to handle the specific timing requirements expected by the controllers and software during the first revolution after a drive is selected.
For each of the three standard drive selects, the VSG maintains a running average of the last four revolution times so that the timing of virtual sector pulses matches each drive's rotational rate.