File Access Restriction - Mitsubishi Electric MELSEC iQ-R C R12CCPU-V User Manual

File access restriction

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.
• Program memory
• Data memory
• SD memory card
• USB Mass Storage Class-compliant device
• When an SD memory card or a USB Mass Storage Class-compliant device is inserted to a peripheral device
other than a C Controller 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 and the USB Mass
Storage Class-compliant device, take appropriate measures so that the SD memory card and the USB
Mass Storage Class-compliant device cannot be removed from the C Controller module at will.
• Access restriction cannot be set for folders.
File access restriction setting
Change a file attribute handled in a C Controller 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 Controller 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 a file is opened by specifying a file name, the file can be operated. To prohibit file operations, make sure to set a 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 :
R : Indicates the read-only attribute is specified.
Blank :
S :
Indicates the system file attribute is specified.
Blank :
4 BASIC FUNCTIONS
72
4.13 Security Function
Description
File operations 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.
Indicates the hidden file attribute is not specified.
Indicates the read-only attribute is not specified.
Indicates the system file attribute is not specified.