1 02/05/86  create_dm_file
 2 
 3 Syntax as a command:  create_dm_file path {-control_args}
 4 
 5 
 6 Function: creates an unpopulated data management (DM) file for use
 7 with Multics data management (see the Programmer's Reference Manual).
 8 Files created in this manner would be used primarily for test purposes
 9 or in applications calling the file_manager_ subroutine directly.
10 
11 
12 Arguments:
13 path
14    is the pathname of the DM file to be created.
15 
16 
17 Control arguments:
18 -concurrency, -conc
19    provides automatic concurrent access protection to a protected DM
20    file by enforcing locking conventions on get and put operations to
21    the file (see "Notes").  (Default)
22 -no_concurrency, -nconc
23    turns concurrency protection off for a protected DM file, saving on
24    overhead when locking is unnecessary (see "Notes").
25 -no_rollback, -nrlb
26    turns the rollback capability off for a protected DM file, saving on
27    overhead when rollback is unnecessary (see "Notes").
28 
29 
30 -protected, -prot
31    creates a protected DM file, which means the file is entitled to the
32    protection features provided by the integrity services of data
33    management.  You can access a protected DM file only within the
34    context of a transaction.  (See "Notes.") (Default)
35 -ring_brackets W {R}, -rb W {R}
36    sets the write ring bracket to W and the read ring bracket to R.  If
37    you don't specify the read ring bracket, it defaults to the value
38    given for the write ring bracket.  Both R and W must be greater
39    than, or equal to, your validation level.
40 
41 
42 -rollback, -rlb
43    provides an automatic rollback capability for a protected DM file,
44    by logging before images of modifications made to the file.  These
45    images are used in the event of transaction, process, or system
46    failure to restore the file to its original state.  (See "Notes.")
47    (Default)
48 -unprotected, -unprot, -not_protected, -nprot
49    creates an unprotected DM file, without the benefit of integrity
50    services.  You can access an unprotected DM file outside a
51    transaction.  (See "Notes.")
52 
53 
54 Access required: You need sma access on the directory in which the DM
55 file is created and s access on the directory containing that
56 directory.
57 
58 
59 Notes: The -unprotected control argument is mutually exclusive with
60 -concurrency, -no_concurrency, -no_rollback, -protected, and -rollback.
61 If you use two mutually exclusive control arguments, the rightmost
62 option in the command line takes precedence.
63 
64 This command is part of the command level interface to Multics data
65 management.