[TUHS] the guy who brought up SVr4 on Sun machines

Joerg Schilling schily at schily.net
Thu Jan 12 20:39:28 AEST 2017


Larry McVoy <lm at mcvoy.com> wrote:

> I really wonder where you got your information from because it's a
> little bit wrong.

Do you really believe I invented all these people? You already confirmed that 
they exist. How do you believe, I could get the names without being in contact 
with them?

I got my information from working on Solaris and in this special case, you seem 
to forget that you definitely made a mistake. Maybe you now like to refresh 
your memory....

>From Solaris sys/vfs.h:

/*
 * Filesystem type switch table.
 */

typedef struct vfssw {
        char            *vsw_name;      /* type name -- max len _ST_FSTYPSZ */
        int             (*vsw_init) (int, char *);
                                /* init routine (for non-loadable fs only) */
        int             vsw_flag;       /* flags */
        mntopts_t       vsw_optproto;   /* mount options table prototype */
        uint_t          vsw_count;      /* count of references */
        kmutex_t        vsw_lock;       /* lock to protect vsw_count */
        vfsops_t        vsw_vfsops;     /* filesystem operations vector */
} vfssw_t;

I however have to admit that I did also a mistake as struct vfssw just 
contains the structure vfsops_t and is not the structure I had in mind itself.

But it is based on struct vfssw from SunOS-4 sys/vfs.h which looks this way:

/*
 * Filesystem type switch table
 */
struct vfssw {
        char            *vsw_name;      /* type name string */
        struct vfsops   *vsw_ops;       /* filesystem operations vector */
};


It seems that "porting" it to Svr4 caused a dot to be appended to the 
comment ;-) 

BTW: in 1990 with SunOS-4.0, I could already modload my "wofs" as I added a few
nulled entries to the struct vfssw in os/vfs_conf.c, pretended that wofs was a 
device driver and let it then install itself into one of the empty entries in
struct vfssw.

Jörg

-- 
 EMail:joerg at schily.net                  (home) Jörg Schilling D-13353 Berlin
       joerg.schilling at fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/
 URL:  http://cdrecord.org/private/ http://sourceforge.net/projects/schilytools/files/


More information about the TUHS mailing list