Files and File Extensions

This topic contains information about the various files and file extensions used in Library Manager.

For information about .TopCat and .Cat files, see Category Management.

C-level Database Access (CDBA) File Extensions

A C-level Database Access (CDBA) file has five possible extensions as follows:

Extension	Description
.cdb	Contains design data, such as  schematic, layout, behavioral, or user-customized. For example, Cadence software reads the sch.cdb file when you open a schematic for editing. To open this file using SKILL,  use the dbOpenCellViewByType function.
.cd%	Contains cellview information between saves. It is a backup CDBA file.
.cd+	The system maintains this file. It is a temporary auto-save CDBA file.
.cd-	Panic CDBA file Contains panic information in the case of a program crash. You can access this file using the dbOpenPanicCellView SKILL function. It is a panic CDBA file.
.cd?	It is a corrupted CDBA file.

The library directory might also contain a techfile.cds file, which is the technology database if the library is a technology library.

OpenAccess File Extensions

An OpenAccess file has a .oa extension. This file contains design data, whether it is schematic, layout, behavioral, or user-customized. For example, Cadence software reads the sch.oa file when you open a schematic for editing. To open this file using SKILL, you can use the dbOpenCellViewByType function.

The library directory might also contain a tech.db file, which is the technology database if the library is a technology library.

data.dm File

The property bag file contains object properties.For OpenAccess 2.2, the file is called data.dm.

The contents of this file depend on its location as follows:

Location	Contents
Library directory	Properties that affect the entire library, such as the technology binding
Cell directory	Cell properties, such as CDF descriptions
View directory	Cellview properties

You can use the SKILL functions described under in Virtuoso Studio Design Environment SKILL Reference to access property bag data.

pc.db File

The pc.db file contains on-disk parent/child relationship information for a cellview, that is, information as of the last dbSave, as opposed to what might be in virtual memory.

The following tasks and applications use the pc.db file:

• Hierarchical copy
• Hierarchy Editor
• Schematic editor hierarchy traversal function, which many applications use

If pc.db file exists, hierarchical copy reads the pc.db file to get the parent-child information. Otherwise, hierarchical copy extracts the parent-child information directly from OpenAccess database.

The pc.db file allows the traverser to navigate through other non-CDBA data descriptions such as VHDL and Verilog while avoiding the differences in VM CDBA.

Only the super master (<library>.<default_subcell>) is physically saved on disk. Therefore, when the copy command is executed using Library Manager, only that subcell is copied to the destination library.

master.tag File

The master.tag file contains master information for a cellview. The master information determines what tool to use when you edit a cellview.

The master.tag file might contain any of the following:

• sch.oa
• layout.oa
• text.txt
• verilog.v

Related Topics

Viewing and Changing File Permissions

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