History of the Portable Network Graphics (PNG) Format
So where are we today? The future is definitely bright for PNG, and the present isn't looking too bad, either. I now have over 125 applications listed (Reference 10) with PNG support either current or planned (mostly current). Among the ones available for Linux are:
XV: image viewer/converter
ImageMagick: image viewer/converter
GRAV: image viewer
Zgv: image viewer
xli: image viewer
XPaint: image editor
The GIMP: image editor
Image Alchemy: image converter
pnmtopng/pngtopnm: image converters
XEmacs: editor/web browser/operating system/etc.
gforge: fractal terrain generator
Fractint: fractal generator
Ghostscript: PostScript viewer/converter
GNUplot: plotting program
PV-WAVE: scientific visualization program
VRweb: VRML browser
X Mosaic: web browser
Arena: web browser
Chimera: web browser
Grail: web browser
Amaya: web browser/editor
Mapedit: image map editor
WWWis: HTML IMG sizer
file(1): Unix file type identifier
Discerning readers will note the conspicuous absence of Netscape Navigator. Netscape is still only “considering” future support of PNG despite the following facts:
Netscape was aware of the PNG project from the beginning and unofficially indicated “probable support.”
The benefits brought to WWW applications by gamma correction, alpha support and 2D interlacing.
The WWW Consortium, of which Netscape is a member, released the PNG spec as its first official Recommendation.
Support of PNG is required in VRML 2.0 viewers like Netscape's own Live3D plug-in.
Netscape has received considerable pestering by members of the PNG group and the Internet community at large.
Until Netscape either supports PNG natively or gets swept away by Microsoft or someone else, PNG's usefulness as an image format for the Web is considerably diminished.
On the other hand, our friends at Microsoft recognized the benefits of PNG and apparently embraced it wholeheartedly. They have not only made it the native image format of the Office97 application suite but have also repeatedly promised to put it into Internet Explorer. (Theoretically by the time of the 4.0 betas—we'll see if that happens.) Assuming they do, Netscape is almost certain to follow suit. (See? Microsoft is good for something!) At that point PNG should enjoy a real burst of WWW interest and usage.
In the meantime, PNG viewing actually is possible with Linux Netscape; it's just not very useful. Rasca Gmelch is working on a Unix plug-in with (among other things) PNG support. Although it's still an alpha version and requires ImageMagick's convert utility to function, that's not the problem, Netscape's brain-damaged plug-in architecture is. Plug-ins have no effect on HTML's IMG tag: if there's no native support for the image format and no helper application defined, the image is ignored regardless of whether an installed plug-in supports it. Instead you must use Netscape's EMBED extension. That means anyone who wants universally viewable web pages loses either way: PNG with IMG doesn't work under Netscape, and PNG with EMBED doesn't work under much of anything except Netscape and MSIE, and then only if the user has installed a working PNG plug-in.
However, support by five or six other Linux web browsers isn't bad, and even mainstream applications like Adobe's Photoshop now do PNG natively. More are showing up every week. Life is good.
As VRML takes off—which it almost certainly will, especially with the advent of truly cheap, high-performance 3D accelerators—PNG will go along for the ride. JPEG, the other required VRML 2.0 image format, doesn't support transparency. Graphic artists will use PNG as an intermediate format because of its lossless 24-bit (and up) compression, and as a final format because of its ability to store gamma and chromaticity information for platform independence. Once the “big name” browsers support PNG natively, users will adopt it as well—for the 2D interlacing method, the cross-platform gamma correction, and the ability to make anti-aliased balls, buttons, text and other graphic elements that look good on any color background. No more “ghosting,” thanks to the alpha-channel support.
Indeed, the only open issue is support for animations and other multi-image applications. In retrospect, the principal failure of the PNG group was its delay in extending PNG to MNG, the “Multi-image Network Graphics” format. As noted earlier, everyone was pretty burned out by May 1995; in fact, it was a full year before serious discussion of MNG resumed. As (bad) luck would have it, October 1995 is when the first Netscape 2.0 betas arrived with animation support, giving the (dying?) GIF format a huge resurgence in popularity.
At the time of this writing (mid-January 1997), the MNG specification has undergone some 31 drafts—almost entirely written by Glenn Randers-Pehrson—and is close to being frozen, although there has been a recent burst of new activity. A couple of special purpose MNG implementations have been written, as well. But MNG is too late for the VRML 2.0 spec, and despite some very compelling features, it may never be perceived as anything more than PNG's response to GIF animations. Time will tell.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
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With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide