This paper describes a process for using content stored on a local CD-ROM in a remote, live website. The relationship between such websites and discs is described as a Web/CD symbiosis, as it is an interdependent relationship, allowing designers to create sites using high quality content without the problems of delivery across a slow network. An online professional development project using this technique is discussed and some of the software used to create content for such a disc is detailed.

Background

This paper is based on the experience gained from some work that I have been carrying out for number of years for now. For some time I've been experimenting with ways of delivering high quality content to users of the Web while not placing heavier demands on the Internet connection that they use. This is particularly a problem if they are using a slow modem, such as a 14.4 or 28.8 K. connection. The use of streaming audio and video goes some way towards overcoming this problem, however, particularly when using video, the results are less than optimal. W3C (http://www.w3.org/) has been developing a language which will eventually overcome some of these problems, but synchronised multimedia still works best over a fast Internet connection.¹

While I was working as a lecturer at the RMIT Sunrise Research Laboratory, Liddy Nevile and I developed a range of CD ROMs which behaved as small, local Internets.² They were essentially collections of websites stored on the CD, which uses could browse through locally without the need of an Internet connection. All the software needed was included on the disc, and these discs were used extensively in professional development of teachers in Victoria and in other states around Australia. Because the discs were web based, we could include links to the live versions of the sites, which meant that if the user had an Internet connection they could visit an updated version of the material included on the CD. Liddy Nevile described these discs as "CDs with a hole in them". Video and audio content could be added to these discs, and, depending on the speed of the CD-ROM drive, played from the CD-ROM. A key advantage of the discs was that the content could be indexed, giving users easy access to anything included on the disc. It had been anticipated that future discs would include a search engine as well, but unfortunately the project came to a halt before this eventuated. A discussion of the design of the OZeKIDS discs is available at the Sunrise website.³

These discs work very well for static content from the Web but have difficulty in capturing dynamic content, such as database-backed websites. As a stand-alone product, the discs can't use any content that relies on intervention by a server. This often meant that sites which were captured for discs had to be extensively reworked before they were suitable for CD-ROM. Putting aside this limitation, any of the standard mime types can be included on disc and displayed through a web.

The OzEKids range of CDs was highly successful, and variations of this format have now been used by a wide range of educational entities and other organisations.

Web/CD symbiosis

One problem that I have identified with this type of disc is that the content is necessarily static, leading to situations where the content becomes outdated, often unnecessarily. For a while now I've been experimenting with ways of combining live websites with static content from CDs. My goal was to create a CD-ROM that contained high bandwidth material which could be given to users, who could use the disc either while looking at live websites or as a stand-alone product. Web pages could point to multimedia content on the CD-ROM, rather than using streaming audio or video from a server. I envisaged that this would be particularly useful for high-quality video footage. I have heard of other projects that seemed to be providing a similar type of solution, but still have not seen any examples of these discs.

In order to do use a CD-ROM in this manner I needed to develop a method that would allow users to identify the CD-ROM drive of their computer. This was necessary because CD-ROM drives on PCs do not always use the same drive letter. A floppy drive is conventionally named A, while the first hard drive on a computer is usually named C. The first CD-ROM drive is usually called D, but if other devices, such as additional hard drives or external backup devices are added to a computer it is not uncommon for these devices to be given device letters first and then a letter assigned to the CD-ROM drive. Some computers will contain several hard drives, and the CD-ROM drive may be labelled G, or H. If there is more than one CD-ROM drive in the computer, it might happen that a user would prefer to use the second drive, for reasons of speed, ease of access, and so on. Macintosh computers cause less of a problem, as the CD-ROM drive only appears when there is a CD-ROM loaded, and then it uses the name of the disc rather than a drive letter.

A javascript was developed to use in web pages where content could be accessed from a local CD-ROM rather than the website. The script asks users to identify the drive letter for the CD-ROM drive being used, or to identify that they are using a Macintosh computer. The drive letter is treated as a variable, which can be used in a string as part of a URL, allowing the URL to find the appropriate local drive on a user's computer.

An issue that needed to be addressed when developing a site that used this javascript was that of "state". The script used only applies to links while the web page that contains the script is open, so it was necessary to develop a site that either kept a window open for the page with the javascript, or to create a site that used frames. Eventually, it was decided to use a framed website, with one of the pages in the frameset being reserved for the page containing the javascript used to identify the local CD-ROM drive. While the page with the script is open it will affect other parts of the frameset, allowing the user to seamlessly view content as they move through the site, as long as they have the CD-ROM in the drive. Other javascript solutions were considered, but were rejected because of incompatibility with either Internet Explorer or Netscape Navigator. Functionality in version 3 or above in either browser was considered essential, as was a solution that would work for both PCs and Macintosh computers.

This style of CD-ROM could be used in a number of situations. One possible application would be to create a version of a website, including all of the video and audio resources, and place it on a CD-ROM to use as a stand-alone Web/CD, following the model of the OZeKIDS discs. The home page on the CD-ROM could contain a link to the live version of the website, allowing users to gain access to the most recent version of the text content of the site when they do have Internet access, without stopping them from using the contents of the CD-ROM when they don't have access to the web. This would allow the creators of a website to update and rearrange their content as needed, while still being able to make use of the high bandwidth content available on the CD-ROM that has been distributed. Should the website creators choose to use an existing image, sound or video file from the CD-ROM in a new page on the live website, all they would need to do is create a link to the appropriate file on the CD-ROM. Users with the CD-ROM would then be able to view the new page on the live site and the re-purposed CD-ROM content in that page.

An alternative would be simply to use the CD-ROM as a library of content that the live site refers to. There would be no inherent context to the files on the CD-ROM, and users would only be able to gain context by viewing the live website. This would probably be most useful where version control of documents might be useful. In some circumstances it may be important to ensure that all users of a site were looking at the same document, rather than some looking at an old version on a CD-ROM, while others were referring to the updated version of the document, as it appeared on the live website.

In both cases, using a CD-ROM in this manner would serve to keep major content available only to the intended audience, while still being able to give people a taste of what a website is about. A disc of this type opens the possibility of giving users options in the quality of the content they view. It would be possible to have a streaming version of a clip on a website, for all to see, and a much higher quality version of the same clip included on a CD-ROM that users could place in their CD-ROM drive, if a drive is available. Users would then have a choice of the, usually smaller, low frame rate, streaming file served across the web, or a much higher quality version of the same file, played from the local CD-ROM. There would be applications for this style of CD-ROM in education, either for reasons of bandwidth or security. A CD-ROM storing high bandwidth content could be used to reduce access costs, as well as access times, to websites. This would have application in schools that have only limited bandwidth available and many users trying to use that bandwidth at the same time. If used as a security measure, possession of the CD-ROM could take the place of needing a user ID and password. Users might go to the website of an online course, but without the CD-ROM they would only have limited access to the content of a site, as much of the important content would be only available via the CD-ROM.

One issue that has not yet been explored is the use of such a disc on a networked CD-ROM drive. I haven't tested this configuration but can see no reason why it shouldn't be possible. It would perhaps not be as fast as the disc being located in the user's own computer, but it would certainly be much faster than if the clip were placed on the remote website.

Although I have concentrated on how this might be of use with video and audio, it would equally be of use in the dissemination of other file types, such as Word documents, large image files, PowerPoint presentations, and so on. Any website with a specific audience, with large files to deliver might do well to consider such as solution.

I have started describing the relationship between websites and discs described above as a Web/CD symbiosis, a relationship of mutual benefit or dependence, whereby high bandwidth content is made available to users economically, allowing designers to create sites using high quality content without the problems of delivery across a slow network. The site is not complete without the CD-ROM, but the CD-ROM can't be used to full effect without access to the website.

The ACAM Project

The techniques described here have been used in the development of a CD-ROM for the pilot of the online ACAM course (http://www.jcsav.vic.edu.au/acam/). This is a project jointly developed by the Computing in Education Groups of Victoria and Art Education of Victoria, designed to teach teachers how to use Photoshop. As part of the Victorian Department of Education Employment and Training (DEET) Online Professional Development Project, DEET funded Joint Council of Subject Associations of Victoria to assist several subject associations to develop online professional developm,ent programmes. In late 1999 and through early 2000, the ACAM course was reworked to be delivered online. As part of the delivery, a CD-ROM was developed that included a collection of .psd image files and video files. The video files were screen captures that demonstrated the Photoshop techniques covered in the course. Rather than using a video camera, software that captured everything being displayed in a user-selected area of the monitor, at reasonable frame rates, was employed. This has the benefit of excellent clarity, no distortion, and allows the creator to decide which part of the monitor is displayed. The video was captured on a PC, as at the time the project was started there were several pieces of software capable of performing this function, but none available for the Macintosh. The situation has changed somewhat over the last year, and there is now similar software available for the Macintosh.

The technique of capturing video of a computer desktop and storing the results on CD-ROM is not new. It is often used to demonstrate procedures and as a way of providing help files to new users. During 1998 I reviewed a disc from the South Australian Department for Education and Children's Services that employed this technique, though the clips were not used within a website or within HTML pages.⁴

When developing the ACAM CD-ROM an auto-run file was included with a link to the ACAM website, giving PC users an easy way to connect to the online professional development material. When Macintosh users insert the disc a window automatically opens, but no applications start up until the user clicks on an icon for an HTML page contained on the CD-ROM. This HTML page acts as a splash screen, and contains a link to the live site.

As may be gathered from above, the CD-ROM created for the ACAM project is a hybrid disc capable of running on PC as well as Macintosh computers. This is normally quite important when designing for a diverse audience, and is particularly important when the audience is one that is probably more likely to use Macintosh computers than any other section of the teaching profession. Designing a CD-ROM for both platforms requires considerable attention to detail. There are several excellent websites that describe at least part of the process involved in creating discs that use the ISO-9660 naming convention. Probably the best of source of information regarding CD-R is maintained by Andy McFadden, which contains an exhaustive list of frequently asked questions.⁵ Another good resource for learning about the techniques involved in developing CD-ROMs is Electronic Publishing on CD-ROM, by Steve Cunninghan and Judson Rosebush.⁶

When running a pilot project of this nature it is possible to burn a small number of CD-R discs for distribution at minimal cost. For small numbers of discs, perhaps up to as many as 150, it is cheaper to use a replication service to burn CD-R discs than it is to have a glass master created and a larger number of discs pressed. For larger numbers, there is an economy of scale that makes the development of a glass master worthwhile. For a pilot, there are obvious benefits in being able to make changes to the content of a disc and then create a new master, without worrying about the thousands of the old version of the disc that have suddenly become redundant. At less than $2 per blank CD-R, it will often be cheaper to create and post a CD-ROM of course content than it would be to print and post the paper equivalent.

There is a variety of software available for PCs and Macs for creating videos of what is happening on the desktop. Programs for PCs include the following:

Hypercam, available from Hyperionics at http://www.hyperionics.com/. This program costs US$30.

ScreenCam, available from Lotus at http://www.lotus.com/home.nsf/tabs/screencam, costs US$92.95 and is available in a variety of languages.

MatchWare Screencorder (http://www.matchware.net) costs US$59

For Macintosh computers, SnapzPro, available from Ambrosia Software, at http://www.AmbrosiaSW.com/Products/SnapzPro.html, is available, at a cost of US$40.

For the ACAM project Hypercam was used, as it is the package that I am most familiar with. I have had good reports about Lotus ScreenCam and SnapzPro but chose to keep using one package throughout the development of content for this CD-ROM. The software may be configured to capture the desktop or a specific window, at a user-determined frame rate. Although the software allows for sound to be captured at the same time, it was found that "instant voice-overs" were not practical, and that a script had to be developed and audio added to the video at a later stage, using a non linear video editing program.

Creating and editing such video takes time, but even with little expertise it is possible to create excellent clips in a few hours. Developing a hybrid CD-ROM is not particularly difficult, and CD-ROM burners have reduced to a point where they are easily purchased even for home use, making it possible for the style of disc described here to be created at minimal cost. As a medium for delivering high bandwidth content to users, a local CD-ROM storing content to be accessed from a live website has many uses, and much to commend it. Once the pilots for the online professional development project have been completed and reviewed, it is hoped that the subject associations involved will further develop their projects, making use of Web/CD symbiosis techniques in the process.

 

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