Criticism of Adobe Flash

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Simple animation in Flash 6.0; a square moving across the screen in a motion tween, one of the basic functions of Flash.

Adobe Flash as a format has become very widespread on the desktop market and created a market dominance. Adobe Systems claims that 98 percent of US Web users and 99.3 percent of all Internet desktop users have the Flash Player installed,^[1][2] with 45%–56%^[3] (depending on region) having the latest version. Numbers vary depending on the detection scheme and research demographics. The Flash Player has been criticized for requiring lot of computing power and therefore not performing well on weaker machines.^[4]

[edit] Usability

Many usability concerns regarding Flash concern Flash's numerous breaks with many conventions associated with normal HTML pages. Things like selecting text, scrollbars,^[5] form control and right-clicking act differently than with a regular HTML webpage, and it is argued that this contributes to a usability issue. Usability expert Jakob Nielsen published an Alertbox in 2000 entitled, Flash: 99% Bad^[6] which listed many of these issues. Much of this criticism is due to poor implementation. For example, bookmarking could be handled, but is often not implemented due to time, cost, or lack of knowledge.

Web pages which make heavy use of Flash can also cause difficulties for some users, such as those using old hardware or who cannot install or use Flash Player. As Flash elements often include a lot of graphics and sound, dial-up internet users are also affected by higher page load times, although there is a more general trend toward larger websites as high-speed internet becomes more common.

On Linux, it is not possible to scroll a web page with the mouse while the cursor is held over flash content. Scrolling with the arrow keys may require a click on the page outside the flash. News sites may be troublesome to scroll through, as they are often cluttered with flash advertisements, so that one must slalom the cursor around the flash content while scrolling. This way, Flash appears as an unnecessary obstacle, contributing to the impression of poor integration and provides a source of irritation when using a not so optimal mouse, such as a laptop touchpad.

If Flash Player is not installed in Firefox, Firefox will prompt the user to install it when a website with flash content is encountered. This happens even if Firefox is unable to install it, such as when using a 64-bit OS. Even worse, Firefox does not remember how many times the user have refused it before or how many times this installation has failed. The procedure to disable this feature is simple, but requires knowledge of the special "about:config" page in Firefox and resetting the counter-intuitively named boolean "plugin.default_plugin_disabled", which is enabled by default.

[edit] Accessibility issues

The US Justice Department has stated in regard to the Americans with Disabilities Act of 1990:

"Covered entities under the ADA are required to provide effective communication, regardless of whether they generally communicate through print media, audio media, or computerized media such as the Internet. Covered entities that use the Internet for communications regarding their programs, goods, or services must be prepared to offer those communications through accessible means as well."

Although long since fixed with accessibility functions since Flash Player 6, Internet users who are visually-impaired, and who may rely on a screen reader, braille display, or using larger text sizes and/or high-contrast color schemes may find sites that make extensive use of Flash difficult or impossible to use.^[7]

[edit] Use for restricting access to content

Many content producers use Flash as a way to limit user's access to the media displayed in their browsers, and/or gain clicks by forcing extra steps to display. For example, in Windows, Shockwave/Flash (.swf) files cannot be right-clicked and saved. Famously, YouTube furnishes all video in flash video format (.flv), requiring users to turn to third-party solutions to store the content locally. The usage is now spreading to photo sharing websites such as Webshots. A Flash overlay exists over the initial photo displayed, requiring a second click to retrieve the photo, slowing the experience considerably. However, if Flash is not installed, the image displays normally.

[edit] Local Shared Objects

Main article: Local Shared Object

Flash Players since version 6 can store and retrieve persistent data without offering any visible signs to the user, similarly to cookies. It is possible to clear the temporary files that Flash stores on a computer either through the Flash website, or manually. The default storage location for LSOs is operating-system dependent. For Windows XP, the location is within each user's Application Data directory, under Macromedia\Flash Player\#SharedObjects. For Windows Vista it is in each user's AppData directory under Roaming\Macromedia\Flash Player\#SharedObjects. For Mac OS X it is in each user's Library directory under Preferences/Macromedia/Flash Player/#SharedObjects. On Linux it is in each user's directory: ~/.macromedia/Flash_Player/#SharedObjects.

[edit] Security issues

Specially crafted files have been shown to cause Flash applications to malfunction, by allowing the execution of malevolent code. Users who have not updated their Flash Player to the most recent version may be vulnerable to such an attack.

In addition to over 100 entries in the Open Source Vulnerability Database, security advisories published in August 2002,^[8] December 2002^[9] and November 2005^[10] highlight three examples of reports about various Flash Player versions that allowed remote code execution.

[edit] Flash Player on various platforms

The Adobe Flash Player is mainly optimized for the Windows 32 bit platform. 32 bit editions of version 9 are also available for Mac OS X, Linux, and Solaris. Although Flash Player 9 resolved important performance and compatibility issues on non-Microsoft platforms, it still has lower performance on some operating systems and may have problems with working properly. In some cases, Gnash may actually work better.

As of May 2008, Adobe has yet to release a Flash Player for the x86-64 architecture on any operating system.^[11] There is to date no Linux Flash Player for non-x86 compatible processors (e.g. x86-64 native, PowerPC, ARM, etc.).^{[citation needed]} Adobe employees have said the Flash implementation is very 32-bit specific and porting to 64-bit systems would require a lot of effort.^[12] Adobe claims to be currently working on a 64-bit version.^[13] Adobe has not yet released any of their development software for any Unix-like operating system except Mac OS X.

On Linux, sound output from Flash Player 9 may not work on certain combinations of Linux distribution and hardware.

Since Adobe has declined to support the PowerPC architecture, the latest Flash fails not only for Linux, but also for Sony Playstation 3, whose Cell processor is based on the POWER architecture. As a result, the PS3 web browser uses an obsolete version of Flash (licensed from Macromedia) that is not compatible with most modern websites.

[edit] Resolved issues

Adobe has rewritten the bitmap drawing routines in Flash Player 8 for Mac, using OpenGL planes via Quartz to draw the surfaces. The new drawing code is reported to be actually faster than its Windows counterpart^{[citation needed]}, where JPEG, TIFF or other bitmap images are composited into the animation.

The Linux version of the Flash Player requires the Advanced Linux Sound Architecture (ALSA) to output sound. ALSA was introduced in Linux 2.5 and may be difficult to use with very old sound hardware. Users of the legacy Open Sound System must either compile and install the abstraction layer flashsupport provided by Adobe, run the Windows Flash Player in a Windows browser through WINE, or switch to ALSA, which may involve recompiling or upgrading the kernel and/or installing additional drivers.

Flash Player 7 for Linux was very CPU hungry in fullscreen mode, resulting in low frame rates. Also, the sound could lag about a second behind the picture; this issue was resolved in Flash Player 9. Flash Player 8 was never released for Linux, Adobe stated that they would skip that version and instead focus on preparing Flash Player 9. Flash Player 9 for Linux was released in January 2007.

[edit] Search engine indexability

Flash files are binary data, and so are not as easily indexable as other document formats. Also, due to their dynamic nature, often it's not possible for a search engine to link to a specific section in an all-Flash site.

Some methods have emerged to try deal with this problem. Adobe has a Flash Search Engine SDK, and Flash CS3 creates additional meta information that is indexable by search engines.^[14] One approach which has become popular is creating a base HTML page with indexable content, and adding an additional flash layer. This method of 'progressive enhancement' has become more popular in recent years.^[15]

[edit] Digital rights management

The latest iteration of Flash allows copyright holders to embed ads within videos, as well as control how those videos are used. With this latest piece of software, companies will be able to quickly remove any video that they feel violates copyright and force advertisements to play prior to the start of the video.

[edit] References