enum {	Maxtrack	= 200,	Ntrack		= Maxtrack+1,	BScdrom		= 2048,		/* mmc data block size */	BScdda		= 2352,	BScdxa		= 2336,	BSmax		= 2352, 	Maxfeatures	= 512, 	/* scsi peripheral device types, SPC-3 §6.4.2 */	TypeDA		= 0,		/* Direct Access (SBC) */	TypeSA		= 1,		/* Sequential Access (SSC) */	TypeWO		= 4,		/* Worm (SBC)*/	TypeCD		= 5,		/* CD/DVD/BD (MMC) */	TypeMO		= 7,		/* rewriteable Magneto-Optical (SBC) */	TypeMC		= 8,		/* Medium Changer (SMC) */ 	/* MMC device types */	Mmcnone	= 0,	Mmccd,	Mmcdvdminus,	Mmcdvdplus,	Mmcbd, 	/* disc or track types */	TypeNone	= 0,	TypeAudio,	TypeAwritable,	TypeData,	TypeDwritable,	TypeDisk,	TypeBlank, 	/* disc writability classes */	Readonly	= 0,		/* -ROM */	Write1,				/* -R: write once only */	Erasewrite,			/* -R[WE]: erase then write */	Ram,				/* -RAM: read & write unrestricted */ 	/* tri-state flags */	Unset		= -1,	No,	Yes, 	/* offsets in Pagcapmechsts mode page; see MMC-3 §5.5.10 */	Capread		= 2,	Capwrite	= 3,	Capmisc		= 5, 	/* device capabilities in Pagcapmechsts mode page */	Capcdr		= 1<<0,		/* bytes 2 & 3 */	Capcdrw		= 1<<1,	Captestwr	= 1<<2,	Capdvdrom	= 1<<3,	Capdvdr		= 1<<4,	Capdvdram	= 1<<5,	Capcdda		= 1<<0,		/* Capmisc bits */	Caprw		= 1<<2, 	/* Pagwrparams mode page offsets */	Wpwrtype	= 2,		/* write type */	Wptrkmode,			/* track mode */	Wpdatblktype,	Wpsessfmt	= 8,	Wppktsz		= 10,		/* BE ulong: # user data blks/fixed pkt */ 	/* Pagwrparams bits */	Bufe	= 1<<6,	/* Wpwrtype: buffer under-run free recording enable */	/* Wptrkmode */	Msbits	= 3<<6,		/* multisession field */	Msnonext= 0<<6,		/* no next border nor session */	Mscdnonext= 1<<6,	/* cd special: no next session */	Msnext	= 3<<6,		/* next session or border allowed */	Fp	= 1<<5,		/* pay attention to Wppktsz */ 	/* close track session cdb bits */	Closetrack	= 1,	Closesessfinal	= 2,	/* close session / finalize disc */	Closefinaldvdrw	= 3,	/* dvd-rw special: finalize */	/* dvd+r dl special: close session, write extended lead-out */	Closesessextdvdrdl = 4,	Closefinal30mm	= 5,	/* dvd+r special: finalize with ≥30mm radius */	Closedvdrbdfinal= 6,	/* dvd+r, bd-r special: finalize */ 	/* read toc format values */	Tocfmttoc	= 0,	Tocfmtsessnos	= 1,	Tocfmtqleadin	= 2,	Tocfmtqpma	= 3,	Tocfmtatip	= 4,	Tocfmtcdtext	= 5, 	/* read toc cdb[1] bit */	Msfbit	= 1<<1, 	/* write types, MMC-6 §7.5.4.9 */	Wtpkt	= 0,		/* a.k.a. incremental */	Wttrackonce,	Wtsessonce,		/* a.k.a. disc-at-once */	Wtraw,	Wtlayerjump, 	/* track modes (determine: are these also track types?) */	Tmcdda	= 0,		/* audio cdda */	Tm2audio,		/* 2 audio channels */	Tmunintr = 4,		/* data, recorded uninterrupted */	Tmintr,			/* data, recorded interrupted (dvd default) */ 	/* data block types */	Dbraw = 0,		/* 2352 bytes */	Db2kdata = 8,		/* mode 1: 2K of user data */	Db2336,			/* mode 2: 2336 bytes of user data */ 	/* session formats */	Sfdata	= 0,	Sfcdi	= 0x10,	Sfcdxa	= 0x20, 	/* Cache control bits in mode page 8 byte 2 */	Ccrcd	= 1<<0,		/* read cache disabled */	Ccmf	= 1<<1,		/* multiplication factor */	Ccwce	= 1<<2,		/* writeback cache enabled */	Ccsize	= 1<<3, /* use `cache segment size', not `# of cache segments' */	Ccdisc	= 1<<4,		/* discontinuity */	Cccap	= 1<<5,		/* caching analysis permitted */	Ccabpf	= 1<<6,		/* abort pre-fetch */	Ccic	= 1<<7,		/* initiator control */ 	/* drive->cap bits */	Cwrite	= 1<<0,	Ccdda	= 1<<1, 	CDNblock = 12,		/* chosen for CD */	DVDNblock = 16,		/* DVD ECC block is 16 sectors */	BDNblock = 32,		/* BD ECC block (`cluster') is 32 sectors */				/* BD-R are write-once in increments of 64KB */	/*	 * make a single transfer fit in a 9P rpc.  if we don't do this,	 * remote access (e.g., via /mnt/term/dev/sd*) fails mysteriously.	 */	Readblock = 8192/BScdrom,}; typedef struct Buf Buf;typedef struct Dev Dev;typedef struct Drive Drive;typedef struct Msf Msf;		/* minute, second, frame */typedef struct Otrack Otrack;typedef struct Track Track;typedef schar Tristate; struct Msf {	int	m;	int	s;	int	f;}; struct Track{	/* initialized while obtaining the toc (gettoc) */	vlong	size;		/* total size in bytes */	long	bs;		/* block size in bytes */	ulong	beg;		/* beginning block number */	ulong	end;		/* ending block number */	int	type;	Msf	mbeg;	Msf	mend; 	/* initialized by fs */	char	name[32];	int	mode;	ulong	mtime;}; struct DTrack			/* not used */{	uchar	name[32];	uchar	beg[4];		/* msf value; only used for audio */	uchar	end[4];		/* msf value; only used for audio */	uchar	size[8];	uchar	magic[4];}; struct Otrack{	Track	*track;	Drive	*drive;	int	nchange;	int	omode;	Buf	*buf; 	int	nref;		/* kept by file server */}; struct Dev{	Otrack*	(*openrd)(Drive *d, int trackno);	Otrack*	(*create)(Drive *d, int bs);	long	(*read)(Otrack *t, void *v, long n, vlong off);	long	(*write)(Otrack *t, void *v, long n);	void	(*close)(Otrack *t);	int	(*gettoc)(Drive*);	int	(*fixate)(Drive *d);	char*	(*ctl)(Drive *d, int argc, char **argv);	char*	(*setspeed)(Drive *d, int r, int w);}; struct Drive{	QLock;	Scsi; 	int	type;			/* scsi peripheral device type: Type?? */ 	/* disc characteristics */	int	mmctype;		/* cd, dvd, or bd */	char	*dvdtype;		/* name of dvd flavour */	char	*laysfx;		/* layer suffix (e.g., -dl) */	int	firsttrack;	int	invistrack;	int	ntrack;	int	nchange;		/* compare with the members in Scsi */	ulong	changetime;		/* " */	int	relearn;		/* need to re-learn the disc? */	int	nameok;	int	writeok;		/* writable disc? */	/*	 * we could combine these attributes into a single variable except	 * that we discover them separately sometimes.	 */	Tristate recordable;		/* writable by burning? */	Tristate erasable;		/* writable after erasing? */ 	Track	track[Ntrack];	ulong	end;			/* # of blks on current disc */	ulong	cap;			/* drive capabilities */	uchar	blkbuf[BScdda]; 	int	maxreadspeed;	int	maxwritespeed;	int	readspeed;	int	writespeed;	Dev; 	uchar	features[Maxfeatures/8]; 	void *aux;		/* kept by driver */}; struct Buf{	uchar	*data;		/* buffer */	vlong	off;		/* data[0] at offset off in file */	int	bs;		/* block size */	long	ndata;		/* no. valid bytes in data */	int	nblock;		/* total buffer size in blocks */	int	omode;		/* OREAD, OWRITE */	long	(*fn)(Buf*, void*, long, ulong); /* read, write */ 	/* used only by client */	Otrack	*otrack;}; extern int	vflag;