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ZX Interface 1: Difference between revisions
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→Microdrive Data Storage Format
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== Microdrive Data Storage Format == | == Microdrive Data Storage Format == | ||
The microdrive is arranged as an unspecified number of sectors, at a maximum of | The microdrive is arranged as an unspecified number of sectors, at a maximum of 254 sectors, each of 512 Kb, allowing for a theoretical maximum of 127Kb per cartridge. Theoretically it is also possible to exceed this in "Read Only" mode as long as Record 0 of a file can be read before the Interface 1 times out, as the read routine appears to match on name and record number without any reference to sectors. | ||
Each sector consists of two files, each similar. There is the Sector Header, which is a 15 byte file record, or the data record recorded after the sector header, which is 528 bytes, including one "sacrificial byte" on the D1 data line, which does not contribute to the data stored, though could be modified into a high-order byte checksum in the future to improve data integrity on older cartridges. | Each sector consists of two files, each similar. There is the Sector Header, which is a 15 byte file record, or the data record recorded after the sector header, which is 528 bytes, including one "sacrificial byte" on the D1 data line, which does not contribute to the data stored, though could be modified into a high-order byte checksum in the future to improve data integrity on older cartridges. | ||