File Access Restriction Function - Mitsubishi Electric MELSEC iQ-R C User Manual

File access restriction function

A file attribute can be set for the files stored in the following types of memory. By setting a file attribute, access to a target file
can be restricted, and falsification by an unauthorized user and data leakage to outside can be prevented.
• Standard ROM
• SD memory card
• When an SD memory card is inserted to a peripheral device other than a C intelligent function module (such
as a personal computer), files to which the access restriction is set can be operated. If the access restriction
is set for the file in the SD memory card, take appropriate measures so that the SD memory card cannot be
removed from the C intelligent function module at will.
• Access restrictions cannot be set for the folder.
File access restriction function setting
Change a file attribute handled in a C intelligent function module by using the attrib() command. A security password is
required to change a file attribute.
For details on the attrib() command, refer to the manual of VxWorks.
■Setting file attribute
Set a file attribute to a file to be restricted by using the attrib() command.
The file attributes that can be handled in a C intelligent function module are as follows.
Attribute
S System file attribute
*1
R Read-only attribute
*2
H Hidden file attribute
*1 This attribute is not supported by the file access restriction function. However, if it is set, file deletion and file write can be prohibited.
*2 When the file is opened by specifying the file name, file operations can be performed. In order to prohibit the file operations, ensure to
set the system file attribute.
■Checking file attribute
A file attribute which is set can be checked by using the attrib() command.
S R H
H Indicates the hidden file attribute is specified.
Blank Indicates the hidden file attribute is not specified.
R Indicates the read-only attribute is specified.
Blank Indicates the read-only attribute is not specified.
S
Indicates the system file attribute is specified.
Blank
Indicates the system file attribute is not specified.
Description
File attributions can be prohibited.
File deletion and data write can be prohibited.
A file is not listed by using the ls command and it is not displayed at FTP connection.
1 FUNCTION
31
1.4 Security Function
1