GDSII Stream format is the standard file format for transfering/archiving 2D graphical design data. It contains a hiearchy of structures, each structure containing. Beyond that, let me say that the stream format is quite simple. I suspect that the people at Calma put a lot of thought into creating a file that. Learn files and view a list of programs that open them.
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GDSII interpreters will either impose such a limit explicitly, or will impose an implicit limit by running out of memory during recursive operations.
Calma allowed only 64 layers and data types, but the Stream Format has room for of each. Bit 15 rightmost and all remaining bits are reserved for future use and must be cleared. In the MASK list, data types are separated from the layers witha semicolon. A node may have from 1 to 50 pairs of coordinates.
GDS File Extension – What is a .gds file and how do I open it?
For an AREF, the angle rotates the entire array lattice with the individual array elements regidly attached about the array reference point.
The first two bytes of the header contain a count in eight-bit bytes of the total record length. No data present 0. I’ve noticed that some OK, many stream files that were originally written to disk using more modern software also pad the file to a multiple of bytes using NULL characters. Seven stream data types are defined.
Therefore, text elements may look different with other viewers and are often ignored in mask production. This is done by calculation a SHA1 checksum during the save process. While these attributes were designed to correspond to the “layers of material” used in manufacturing an integrated circuit, their meaning rapidly became more abstract to reflect the gdzii that the physical layout is designed.
The least significant bit of the most significant byte is the plexhead flag. In stream files created by non-Calma programs, this should be missing or all field should be 0.
There are values for such things as the beginning of a structure, the beginning of a boundary, the end of a structure, and so on. For AREFs, the entire array lattice is reflected, with the individual array elements riidly attached. Maximum length is characters. It is stored in twos complement format, with the most significant byte first. Various companies including Artwork have developed their own gdsii binary-ascii converters for those who wish to use tools such as Perl, awk or Python to manipulate GDSII data.
Objects contained in a GDS II file are grouped by assigning numerical attributes to them including “layer number”, “datatype” or “texttype”. This appendix omits the description of tape formatting, since disk files and disk file images on tape and other media are now the norm .
This is despite the fact that GDSII is not an open industry standard — it was developed by Calma in the 80’s and the ownership of the specification moved from Calma to GE to Valid to Cadence over the years. Bits 10 and 11, taken together as a binary number, specify the font.
Exactly 1 pair SREF: Order the complete book from SPIE.
SPIE Handbook, Volume 1: Microlithography, Section
It can be used to validate the file with common checksum checkers like sha1sum. Attribute numbers and are reserved for the user integer and user string properties, which existed prior to Release 3.
In database units, may be negative. It is a binary file format representing planar geometric shapes, text labels, and other information about the layout formar hierarchical form. Maximum size is 44 bytes.
These free tools include editors,    viewers,  utilities to convert the 2D layout data into common 3D formats,   utilities to convert the binary format to a human readable ASCII fille  and program libraries. The first is the size of a database unit in user units.
The gdsi was padded with NULL characters so that it was always a multiple of bytes. You must subtract 64 to get the true value. The basic unit of measurement is a nanometer 10 -9 meter Since four byte signed integers are used to describe a coordinate then the integer coordinates can range from from minus 2 31 to plus 2 31 This terminates the MASK records.
GDSII files were originally placed on magnetic tapes. To convert scale-independent text elements as well, select a non-zero default text size value for this option in the setup.
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If this record is omitted, then top-left justification and font 0 are assumed. The third and fourth bytes contain the nunber of rows. Byte swapping is required when reading or writing integers with a little-endian machine, such as a VAX. Bit 14 flags absolute angle. This record must be present if there are any reference libraries bound to the current library. Fortunately, the way the gsdii was created enabled users to extend many of the dejure limitations while maintaining defacto compatibility with the actual architectural underpinnings.
GDS II (Calma GDS II)
Different layers typically represent different processing steps for exposure on separate mask plates. Contains four bytes which specify in database units the extension of a path outline beyond the last point gdsiu the path.
This is 6 bytes for “metal” odd length strings are padded with a null plus 8 for “property” plus 2 times the 2 attributes 4 equals The second is called a “Bit array”. There may be more than one mask in a stream file.