=== F1-Z (5,25") ===
The F1-Z model is based on a later revision of the BASF 6138 type disk drive (81757-001), which offers more configuration options using jumpers. The drive was shipped in a "double step" configuration to use only 40 tracks, and thus the cheaper and more widely available DS DD floppy disks (48 tpi, 180K/side) could be used.
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