Scott, the OS of the Roland VA7 (v 2.01) is 1.48 Mb and requires two 1.44 Mb disks.
The OS of the SD1 (v. 3.0c) is even smaller: just 1.024 Mb and fits completely in one disk.
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Korg Kronos 61 and PA3X-Pro76, Roland G-70, BK7-m and Integra 7, Casio PX-5S, Fender Stratocaster with Fralin pickups, Fender Stratocaster with Kinman pickups, vintage Gibson SG standard.