[Info-vax] CRTL and RMS vs SSIO

[Arne Vajhøj]

On 10/9/2021 10:13 PM, Lawrence D’Oliveiro wrote:
> On Sunday, October 10, 2021 at 1:44:55 PM UTC+13, Stephen Hoffman wrote:
>> Various apps can use range locks or local locking or other
>> synchronization for that, but Linux does offer integrated lock
>> management support.
> 
> Nothing VMS-style. All I can find is this <https://manpages.debian.org/bullseye/manpages-dev/fcntl.2.en.html>, which describes about 3 different styles of locking, all on byte ranges, and all associated with files.
> 
>> I don't recall which Linux version first saw lock manager integration,
>> but it was a while back. In RHEL clusters running GFS2 for instance,
>> that DLM is a fundamental part of file access.
> 
> Might be a Red-Hat-specific feature, then.

The DLM and GFS2 was added to Linux kernel 2.6.19 in 2006.

And it sure does remind one of VMS.

#include <libdlm.h>
int dlm_lock(uint32_t mode,
         struct dlm_lksb *lksb,
         uint32_t flags,
         const void *name,
         unsigned int namelen,
         uint32_t parent,        /* unused */
         void (*astaddr) (void *astarg),
         void *astarg,
         void (*bastaddr) (void *astarg),
         void *range);            /* unused */

vs

int sys$enqw (unsigned int efn, unsigned int lkmode, struct _lksb *lksb, 
unsigned int flags, void *resnam, unsigned int parid, void 
(*astadr)(__unknown_params), unsigned __int64 astprm, void 
(*blkast)(__unknown_params), unsigned int acmode, unsigned int 
rsdm_id,...);

Arne