The Travails of Archiving
Shane Beaman of Sealcorp Computer Products, New Zealand, began wondering about how to deal with drawings that are getting old. The problem of how to archive paper drawings formerly dominated; but now with CAD getting to be more than 30 years old, archiving old digital drawings is an issue.
He wrote: Has anyone ever looked seriously at electronic drawing archiving and recovery? I want to be able to access design data created and stored electronically 15 or more years ago, or archived now for access in future years. How do I get information off old hardware stored on old design software that is possibly no longer readable by today’s software? I guess I would have to keep a copy of the old design software, but I wonder if it will still be readable, or able to be run on the new hardware.
The following article is an abstract of the eBook ‘Best CAD Practices’ by Ralph Grabowski. Graebert is happy to share with you some of the experience accumulated by Ralph as a CAD expert and as compiled in his eBook for which the reference can be found at the bottom of the page. Feel free to share feedback in the comment section below.
Everyone today is encouraged to store information electronically, because it is cheap, reasonably secure from corruption, and large amounts of data can easily be stored. But what happens in 20 to 30 to 40 years time when I need to read or retrieve a design that was created on old software or hardware?
Imagine a consulting firm that has created hundreds of drawings all over the country every day and stores them for many years. When there is a new release of software or hardware, do they retrieve all the old designs, and convert them onto the new hardware or the latest software? I don’t think so.
What happens when a software vendor discontinues a design product or goes out of business, and I need read some old drawings that were created years earlier and I no longer have the software to read them?Says something for sticking with a large vendor who’ll likely be around in some form in years to come. Also, says a lot for keeping printed and bulky documentation on file.
Even if we had a universal data format, we still have the problem of being able to read the drawings off old hardware. With the way the computer industry changes, who knows if we will have the same data storage devices or format devices that can be read in 20 years.
Readers of upFront.eZine gave the same general response: “Yup, ya gotta update those archives with each turn of the technological screw.”
Wrote one reader, “That is exactly what must be done to make CAD data usable. Over a 10-year period, our archives have existed in three different locations and two different CAD formats.”
Another reader wrote, “Bring really important data, such as coordinate data, forward. But at most, leave data one step back.”
A software vendor suggested, “Those who archive paper drawings scan and save them as raster files onto CDs or hard disks. Unlike proprietary CAD file formats, the structure of TIFF, CALS, BMP, etc, raster files are all in the public domain and will be accessible in 20, 30, or 40 years time to anyone willing to decode the format.”
One reader said his firm made the decision to abandon old data. “We made this decision for several reasons: (1) cost and space of maintaining old hardware; (2) converting data requires significant time and does not produce a great product; (3) CAD operators said they preferred to recreate clean data, rather than deal with the mess produced by the port.”
It’s relatively easy to bring old 2D CAD data forward to modern standards. Another reader raised the problem of modern CAD formats. “We don’t think we can store CAD drawings containing 3D, paper space views, and intelligent objects — it will be another problem when it becomes to read such data.”
Other alternatives include cloud services, such as Dropbox or the ones provided by some CAD vendors. A small amount of storage is provided free, typically 2GB – 5GB; after this, you need to pay an annual subscription.
Don Beaton, the technical editor for this book, made the following comments on archiving of CAD data. He wrote:
The discussion of longevity of CAD data needs to be expanded to include issues such as hardware standards, operating systems, hardware drivers, hardware interface boards and cables. For example, computers no longer have parallel or serial ports, and new ones have USB3 or Lighting ports.
There are so many different forms of backup media, all incompatible with each other. In addition, a particular piece of hardware, such as a tape drive, sometimes cannot read tapes [still used today] created on an identical drive due to problems like head-alignment error.
Backup media have other problems, too. There is the destruction of magnetic media due to:
- Elevated temperature: in a car or a corner office on a sunny day
- Fire
- Water damage: flooding or sprinkler systems putting out that fire
- Tape “eaten” by the tape drive; the magnetic pattern on the tape can alter the pattern on adjacent tape if it is not rewound occasionally
- Human error: a valuable disk is discarded, or is reused for new backup
Never discard old backup hardware: you may need it to restore data from obsolete media. The following Web page discusses the long-term view of data storage: www.longnow.com/10klibrary/library.htm
Consideration needs to be given to publishing CAD drawings in formats likely to be viewable in the long term. That means saving the files in a non-proprietary format that can be viewed with free, open source viewers. Almost all CAD formats, including DWG, are proprietary. To be considered non-proprietary, the file format must meet two conditions: (1) the file format must be published; and (2) changes are made to the format by a committee.
One storage format currently popular is Adobe’s PDF. The advantages include: file cannot be altered; file is self-contained (no external font files, for example, are needed); fonts and xrefs are displayed correctly; details can be plotted; format is vector, so it looks good when plotted at various sizes; colleagues can make annotations and comments, which are stored on a separate layer from the data; and the Acrobat reader is free.
Some CAD packages can create a PDF file directly. If your’s cannot, add a PostScript plotter (such as the HP 755cm), and plot the drawing to a PS file. Convert the PS file to PDF format.
ABOUT THE AUTHOR
Ralph Grabowski is a CAD expert with 30+ years experience. He is the author of several best-selling books related to most leading CAD programs. Ralph writes also in a variety of CAD news portals and magazines. More than anything, he is renowned as the founder and editor of the upFront.eZine newsletter and the blog WorldCAD Access.
NB: The views and opinions expressed by the author in this article or in the eBook do not necessarily reflect those of Graebert as a company or publisher of this blog.
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