Applied Mathematics and Mechanics(AMM) is committed to providing long-term access to the digital content they collect and curate. AMM recognizes that collaborative approaches to preserving digital content are essential. AMM works with Chongqing Jiaotong University’s Information Technology Centre and Beijing Magtech Science &Techology Development Co.Ltd to provide secure storage and backup of locally hosted digital content. AMM adheres to best practices for digital preservation to insure data accessibility, fixity and usability.
Preservation Support Levels
Digital objects are assigned a persistent identifier to provide persistent access. Secure storage and backup services are provided for all digital content. AMM will take reasonable steps to ensure the usability of the digital objects placed in the local hosts in Chongqing Jiaotong University’s Information Technology Centre. Preservation steps include format migration, emulation, and normalization (actions that convert an unsupported format to a supported format). The preservation steps performed by AMM is determined by the file format of the digital objects. More extensive actions will be taken to preserve the usability of objects in file formats that are open, fully disclosed, well documented, widely adopted, and most accessible for migration, emulation, or normalization actions. Fewer actions will be taken to preserve usability of file formats that are proprietary and/or undocumented, and those that are considered working formats (e.g., Photoshop .psd) and/or are not widely adopted. The support levels indicated below are:
Bit-Level — AMM commits to maintaining the files on the level of ones and zeroes, but not to maintaining format integrity. This level of support is generally assigned to proprietary formats.
Format —AMM commits to maintaining bitstream and format integrity. This level of support is generally assigned to formats (proprietary or not) for which open standards are available. For instance, if PDF as a format changes substantially, we will endeavor to convert all of our PDF bitstreams to the latest version. One exception to this is HTML, which changes so relatively frequently that the Libraries do not have the resources to ensure format integrity in its case.
File Support and Preservation Best Practices
The following table details AMM’s preservation support levels for commonly used file formats. Best practices for file formats are included.
TEXT AND MICROSOFT OFFICE FILE FORMATS
Format | File | Support Level | Best Practices |
HTML | .html, .htm | Bit-Level | Must include all other referenced files, including CSS files and any includes. |
Microsoft Word | .doc | Bit-Level | Though acceptable for deposit, the best practice is to convert to PDF prior to deposit. |
Microsoft PowerPoint | .ppt | Bit-Level | Disable all macros and other effects. Conversion to PDF is also an excellent option. |
Microsoft Exel | .xls | Bit-Level | Disable all macros. You may also wish to export dataset into a tab-delimited text file (.txt) prior to deposit. |
Format | |||
Postscript | .ps | Format | |
Rich Text | .rtf | Bit-Level | For increased support, you may wish to consider conversion to PDF. |
Plain Text | .txt | Format | It is recommended that .txt files be saved using UTF-* (Unicode) character set. |
SGML | .sgm, .sgml | Bit-Level | Requires that the depositor also include the DTD along with the SGML file. |
XML | .xml | Bit-Level | To ensure the best available support, include the DTD along with a well-formed XML file that is valid according to the included DTD. |
IMAGE FILE FORMATS
Format | File | Support Level | Best Practices |
BMP | .bmp | Bit-Level | |
GIF | .gif | Format | |
JPEG | .jpg | Format | When possible save using no compression. |
JPEG2000 | .jp2 | Bit-Level | This file format holds much potential once tools and support become more widely available. Best practice is to save master files using no compression. |
PNG | .png | Format | |
Photo CD | .pcd | Bit-Level | |
Photoshop | .psd | Bit-Level | |
TIFF | .tif, .tiff | Format | Considered the best format for storing your master images. Best practice is to save these files with no compression. |
AUDIO FILE FORMATS
Format | File | Support Level | Best Practices |
MPEG audio | .mp3 | Bit-Level | |
Real Audio | .ra, .rm, .ram | Bit-Level | Proprietary format. It may be appropriate to convert to another format prior to deposit. |
Wave | .wav | Format | Recommended format for capturing digital audio. This format can store all the data in an uncompressed format and its wide use suggests long-term community support. |
Windows | .wma | Bit-Level |
VIDEO FILE FORMATS
Format | File | Support Level | Best Practices |
AVI | .avi | Bit-Level | |
MPEG-1 | .mp1 | Bit-Level | |
MPEG-2 | .mp2 | Bit-Level | |
MPEG-4 | .mp4 | Bit-Level | |
Quicktime | .mov | Bit-Level | |
Windows Media Video | .wmv | Bit-Level |
