[−][src]Module spectrusty_formats::mdr

MDR file format utilities.

Utilities in this module provide additional methods to the MicroCartridge type with abilities:

to inspect and manipulate sector data on the Microdrive file system level (read, create, erase and list files from cartridges);
to extract files into and from the TAP format;
to write and read MicroCartridge data to and from MDR file format.

MDR files are data images of formatted sectors of ZX Microdrive tape cartridges.

The number of sectors may vary but it will never be a larger than 254.

The last byte determines the write protection flag: if it's not 0 the cartridge should be protected.

The structure of a single cartridge sector saved in the MDR file:

offset	size	ROM var	description
0	1	HDFLAG	Bit 0 if set indicates a header and should always be set.
1	1	HDNUMB	Sector number: starts from 254 down to 1.
2	2	-	Unknown, probably padding.
4	10	HDNAME	Name of the cartridge with trailing spaces, repeated every formatted sector.
14	1	HDCHK	Checksum of the previous 14 bytes.
15	1	RECFLG	Record flags, see below. Bit 0 should be always reset.
16	1	RECNUM	File block record number: starts at 0.
17	2	RECLEN	File block data length (LSB first), less than or equal to 512.
19	10	RECNAM	Name of the file with trailing spaces, repeated every record.
29	1	DESCHK	Checksum of the previous 14 bytes.
30	512	CHDATA	Record block data: 0..RECLEN.
542	1	DCHK	Checksum of the previous 512 bytes, regardless of RECLEN value.

Record flags (RECFLG):

Bit 0 is always reset to indicate a record block descriptor.
Bit 1 is set for the last record block (End Of File).
Bit 2 is set for regular files and reset if the record is part of a PRINT type file (a stream).

The above structure and ROM variable names are from the book by Gianluca Carri "Spectrum Shadow ROM Disassembly".

Structs

CatFile	MicroCartridge's file meta data.
Catalog	The structure returned by MicroCartridgeExt::catalog method.
FileSectorIdsUnordIter	An iterator of sector indices and unordered block numbers belonging to a single file.
FileSectorIter	An iterator of sectors belonging to a single file.
MdrFileHeader	Binary (`SAVE *`) file's header.
MdrValidationError	An error returned when a Sector's content is invalid.
MicroCartridge	This struct represents an emulated Microdrive tape cartridge.
Sector	This struct represents a single MicroCartridge tape sector.
SectorBlock	Instances of this type are returned by FileSectorIdsUnordIter iterator.

A MicroCartridge's file type.

HEAD_SIZE	The size of the sector header in bytes, excluding the 12 preamble bytes.
MAX_USABLE_SECTORS	The maximum number of usable ZX Microdrive tape sectors.

MicroCartridgeExt	Extends MicroCartridge with methods for reading and manipulating Microdrive's file system.
SectorExt	Extends MicroCartridge's Sector with methods for reading and manipulating Microdrive's file system.

Checksum calculating routine used by Spectrum for Microdrive data.