UNIX V6のproc構造体

UNIX V6でのプロセスを表す構造体の定義

メモリに常駐し、この構造体の内容が目まぐるしく変化する

1つのプロセスが以下のような構造体で表される

code:sys/proc.h

struct proc

{

char p_stat; /* プロセスの状態。↓参照 */

char p_flag;

char p_pri; /* priority, negative is high */

char p_sig; /* signal number sent to this process */

char p_uid; /* user id, used to direct tty signals */

char p_time; /* resident time for scheduling */

char p_cpu; /* cpu usage for scheduling */

char p_nice; /* nice for scheduling */

int p_ttyp; /* controlling tty */

int p_pid; /* unique process id */

int p_ppid; /* process id of parent */

int p_addr; /* address of swappable image */

int p_size; /* size of swappable image (*64 bytes) */

int p_wchan; /* event process is awaiting */

int *p_textp;/* pointer to text structure */

} procNPROC;

UNIX V6では6種類の状態を持つことがわかる

code:sys/proc.h

/* stat codes */

#define SSLEEP 1 /* sleeping on high priority */

#define SWAIT 2 /* sleeping on low priority */

#define SRUN 3 /* running */

#define SIDL 4 /* intermediate state in process creation */

#define SZOMB 5 /* intermediate state in process termination */

#define SSTOP 6 /* process being traced */

code:sys/proc.h

/* flag codes */

#define SLOAD 01 /* in core */

#define SSYS 02 /* scheduling process */

#define SLOCK 04 /* process cannot be swapped */

#define SSWAP 010 /* process is being swapped out */

#define STRC 020 /* process is being traced */

#define SWTED 040 /* another tracing flag */