Cisco Model 6109 6 MHz Off-Air Reference (NTSC) Guide De Montage
Software Component Model
4039132 Rev B
13
Persistence
The existence of a USRM software component and its nonvolatile state are
maintained in the persistdata directory. When a software component is created, the
USRM software creates a corresponding component in the persistdata directory. The
format of the filename is:
maintained in the persistdata directory. When a software component is created, the
USRM software creates a corresponding component in the persistdata directory. The
format of the filename is:
typename.instancename.bin
Typename indicates the component type. For example, the typename for a gqam is
"gqam". If three gqams are created with user-assigned names qam001, qam002 and
qam003, then three persistdata files are created named gqam.qam001.bin,
gqam.qam002.bin, and gqam.qam003.bin, respectively.
"gqam". If three gqams are created with user-assigned names qam001, qam002 and
qam003, then three persistdata files are created named gqam.qam001.bin,
gqam.qam002.bin, and gqam.qam003.bin, respectively.
The persistdata file contains a sequence of tag/length/value sequences that contain
the nonvolatile state of data items. Every data item that is marked as persistent of a
software component has a corresponding entry in this file that maintains the state of
the element. On every change-of-state of the data element, the change is output to
this file immediately. Normal caching of disk writes in the operating system inhibit
immediate physical writes to the disk. The USRM design approach depends on file
caching.
the nonvolatile state of data items. Every data item that is marked as persistent of a
software component has a corresponding entry in this file that maintains the state of
the element. On every change-of-state of the data element, the change is output to
this file immediately. Normal caching of disk writes in the operating system inhibit
immediate physical writes to the disk. The USRM design approach depends on file
caching.
When the software is activated the first time after installation, the components are
created and a file is created in the persistdata directory for each component. Upon
termination and restart, the software uses the contents of the persistdata directory to
recreate the software components and restore their states to the state prior to
termination. The presence of a file indicates that the component exists and should be
created. The content of the file is input to recover the exact state of the component.
created and a file is created in the persistdata directory for each component. Upon
termination and restart, the software uses the contents of the persistdata directory to
recreate the software components and restore their states to the state prior to
termination. The presence of a file indicates that the component exists and should be
created. The content of the file is input to recover the exact state of the component.