param.h

著名的AT&T UNIX v6 源码

/*
 * tunable variables
 */

#define	NBUF	32		/* size of buffer cache */
#define	NINODE	150		/* number of in core inodes */
#define	NFILE	175		/* number of in core file structures */
#define	NMOUNT	8		/* number of mountable file systems */
#define	MAXMEM	1024		/* max core in 512-byte clicks */
  /*
   ***********************************************************
   * NOTE: For the moment, MAXUMEM must be less than 12*128  *
   ***********************************************************
   */
#define	MAXUMEM	(MAXMEM - 128)	/* max no. clicks per process */
#define	SWAPSIZE	16		/* granularity of partial swaps (in clicks) */
#define	MAXUPRC	25		/* max processes per user */
#define	SSIZE	4		/* initial stack size (*512 bytes) */
#define	SINCR	2		/* increment of stack (*512 bytes) */
#define	NOFILE	20		/* max open files per process */
#define	CANBSIZ	256		/* max size of typewriter line */
#define	CMAPSIZ	(PHYSPAGES/32)	/* size of core allocation area */
#define	SMAPSIZ	70		/* size of swap allocation area */
#define	NCALL	20		/* max simultaneous time callouts */
#define	NPROC	125		/* max number of processes */
#define	NTEXT	80		/* max number of pure texts */
#define	NCLIST	200		/* max total clist size */
#define	HZ	60		/* Ticks/second of the clock */
#define	TIMEZONE	(5*60)		/* Minutes westward from Greenwich */
#define	DSTFLAG	1		/* Daylight Saving Time applies in this locality */
#define	MSGBUFS	128		/* Characters saved from error messages */
#define	NCARGS	5120		/* # characters in exec arglist */
#define	USRSTACK 0x80000000	/* Start of user stack */
#define PHYSPAGES 2048		/* max number of real memory pages */

/*
 * priorities
 * probably should not be
 * altered too much
 */

#define	PSWP	0
#define	PINOD	10
#define	PRIBIO	20
#define	PZERO	25
#define NZERO	20
#define	PPIPE	26
#define	PWAIT	30
#define	PSLEP	40
#define	PUSER	50

/*
 * signals
 * dont change
 */

#define	NSIG	17
/*
 * No more than 16 signals (1-16) because they are
 * stored in bits in a word.
 */
#define	SIGHUP	1	/* hangup */
#define	SIGINT	2	/* interrupt (rubout) */
#define	SIGQUIT	3	/* quit (FS) */
#define	SIGINS	4	/* illegal instruction */
#define	SIGTRC	5	/* trace or breakpoint */
#define	SIGIOT	6	/* iot */
#define	SIGEMT	7	/* emt */
#define	SIGFPT	8	/* floating exception */
#define	SIGKIL	9	/* kill, uncatchable termination */
#define	SIGBUS	10	/* bus error */
#define	SIGSEG	11	/* segmentation violation */
#define	SIGSYS	12	/* bad system call */
#define	SIGPIPE	13	/* end of pipe */
#define	SIGCLK	14	/* alarm clock */
#define	SIGTRM	15	/* Catchable termination */

/*
 * fundamental constants of the implementation--
 * cannot be changed easily
 */

#define	NBPW	sizeof(int)	/* number of bytes in an integer */
#define	BSIZE	512		/* size of secondary block (bytes) */
/* BSLOP can be 0 unless you have a TIU/Spider */
# define BSLOP	0	/* In case some device needs bigger buffers */
#define	NINDIR	(BSIZE/sizeof(daddr_t))
#define	BMASK	0777		/* BSIZE-1 */
#define	BSHIFT	9		/* LOG2(BSIZE) */
#define	NMASK	0177		/* NINDIR-1 */
#define	NSHIFT	7		/* LOG2(NINDIR) */
#define	UPAGES	4		/* pages of u-area (not including page tables ) */
#define USIZE	(UPAGES + u.u_pcb.pcb_szpt)	/* size of user block (*512) */
#define	NULL	0
#define CMASK	0	/* default mask for file creation */
#define	NODEV	(dev_t)(-1)
#define	ROOTINO	((ino_t)2)	/* i number of all roots */
#define	SUPERB	((daddr_t)1)	/* block number of the super block */
#define	DIRSIZ	14		/* max characters per directory */
#define	NICINOD	100		/* number of superblock inodes */
#define	NICFREE	50		/* number of superblock free blocks */
#define NICMEM	100		/* number of "cheap" free page frames */
#define	CBSIZE	12		/* number of chars in a clist block */
#define	CROUND	0xF		/* clist rounding; sizeof(int *) + CBSIZE -1*/
#define CLKTICK	(1000000/HZ)	/* microseconds in a  clock tick */

/*
 * Some macros for units conversion
 */
/* Core clicks (512 bytes) to segments and vice versa */
#define	ctos(x)	(x)
#define	stoc(x)	(x)

/* Core clicks (512 bytes) to disk blocks */
#define	ctod(x)	(x)

/* inumber to disk address */
#define	itod(x)	(daddr_t)((((unsigned)x+15)>>3))

/* inumber to disk offset */
#define	itoo(x)	(int)((x+15)&07)

/* clicks to bytes */
#define	ctob(x)	(x<<9)

/* bytes to clicks */
#define	btoc(x)	((((unsigned)x+511)>>9))

/* major part of a device */
#define	major(x)	(int)(((unsigned)x>>8)&0377)

/* minor part of a device */
#define	minor(x)	(int)(x&0377)

/* make a device number */
#define	makedev(x,y)	(dev_t)(((x)<<8) | (y))

typedef	struct { int r[1]; } *	physadr;
typedef	int		daddr_t;
typedef char *		caddr_t;
typedef	unsigned short		ino_t;
typedef	int		time_t;
typedef	int		label_t[10];
typedef	short		dev_t;
typedef	int		off_t;

/*
 * Machine-dependent bits and macros
 */
#define	UMODE	PSL_CURMOD		/* usermode bits */
#define	USERMODE(ps)	((ps & UMODE) == UMODE)

#define	BASEPRI(ps)	((ps & PSL_IPL) != 0)