| Last modified: 8 January 1999. |
| Make those coasters... |
This article considers these crucial points:
PracticalitiesYou will need a CD-ROM writer to build your test CD-ROMs. You will also need some software to help you get data onto the CD. There will be some software that comes with your CD-ROM writer, but check out the list below if you are looking for alternatives.CD-R disks cannot be erased, though you can write data more than once. CD-RW disks can be erased and are read/write. Most CD-ROM writers nowadays support both types of disk. A writer with a SCSI interface is recommended, as IDE writers may be more prone to errors. Slow PCs and unbranded disks may similarly result in duff disks. Basic CD-R disks cost only about a pound, while CD-RW disks are a tenner or so.
CDs give you 500 to 600 MB of space. Each time you write a bunch of files to
the CD-ROM, there is an overhead of several MB. So 30MB of files may take
up 40MB of space. For small quantities with not too much data, you can burn each CD yourself, say onto pre-printed blank CD-R disks. You can get label printing systems which use ordinary printers and stick on. They usually have some software to help you fit your design onto the available space. The next stage up is to get printable blank CD-R disks for about £1.50. Professional printing costs about a pound each. The final solution is get a pressing plant to churn out copies. After an initial £300-£400 glass master charge, costs soon come tumbling down: eg 1000 CDs costs about 40p-60p each. You will need colour separated artwork. Don't forget a jewel case (10p) or plastic wallet (6p), and the printed inserts (say 10-20p). Expect the courier in 2 weeks!
Double and triple check your release CD-ROMs. |
In some cases you may be certain that your users will be running Windows 95, 98, NT or 2000 and can tailor your HTML pages to the two big browsers, ie Netscape Navigator (versions 3 and 4) and Microsoft Explorer (versions 3 and 4).
For particular applications you may - for example - be able to stipulate that the user must be running Internet Explorer. In this case, it is a nice touch to provide the appropriate browser for people to install. Both Navigator and Explorer are now free to use.
Similarly, provide any plug-ins or controls that your pages require. Make sure that you are allowed to redistribute any software you include.
Note that some software may require an extra licence for it to be distributed on a CD-ROM.
Nowadays, it is pretty safe to assume that PC users will be running Navigator 3 or 4 or Explorer 3 or 4. Both these browsers support JavaScript and Java but they may not be enabled. Some people might even browse a CD-ROM with image loading turned off. Note that it is not safe to assume that all browsers can run the latest JDK 1.1 Java applets. Similarly, you should assume that only Explorer users can run ActiveX controls. Get signed Java applets and ActiveX controls if possible.
As for web sites, JavaScript and Java applets (written to the JDK 1.0 specification) remain the best way of providing interaction that should work in most browsers.
Try to provide a fall-back, eg for the many Windows 3.1 users out there who may not be able to see full filenames or run all the plug-ins you supply.
A CD-ROM is much more suited to showing videos and playing audio than a web site so you may want to include these to liven up your CD-ROM.
Oh, and - as for web sites - provide HTML pages in the language(s) of the target
audience.
No server is available
Obviously when on a CD-ROM, your HTML pages have no server available.
So any scripts and database access will not work. Incidentally, you may not realise that you are using your server - eg FrontPage may generate code that accesses server in special ways.
One simple course of action is simply to cut out the HTML pages which refer to these server functions. A neat solution is to provide an absolute link to your web site. Point out that users must be online for this to work.
Java applets and ActiveX controls will be able to work from a CD-ROM.
While they cannot interact with a server, they can still read data files
from the CD-ROM.
They may be able to interact with a user's databases using JDBC and ODBC.
See the notes below about Java program filenames.
File names and Disk formats
Standard CD-ROMs are in ISO 9660 format which only allows for "8.3" filenames,
ie in capital letters with a maximum of 8 characters, a period, then a maximum
of 3 characters. Directories can only be 8 levels deep.
However the Rock Ridge extensions and Joliet formats allow full filenames. Note that these disks are usually readable by systems which only recognise "8.3" filenames. A filename of "software.html" on a Windows 3.1 system would appear as "SOFTWA~1.HTM". Obviously this will ruin your HTML links.
Unless you change all your filenames, there is no way round this problem, so you may as well issue your CD with full filenames.
Unix does usually cope with full filenames, but the driver may only be able to read ISO 9660 "8.3" disks. Young Minds, Inc. software can install from a "8.3" CD while restoring the full filenames. Use their "makedisc" program to format the CD-ROM, generating the "8.3" filenames and a translation file (YMTRANS.TBL). Users run the "cd_copy" utility to restore the full filenames. Alternatively, the "cd_link" utility makes symbolic links to the actual CD-ROM files.
Apple Macintosh computers can use CDs produced on PC systems, but they can only see the
IS0 9660 "8.3" filenames. Differences in letter case are ignored.
You can be nice to Apple Mac users and produce a dual format CD,
ie where the Apple resource forks are provided.
If your CD includes Java applets you may have some problems on computers which only
recognise "8.3" filenames. This is because Java program filenames always end in ".class" which
cannot be represented as an "8.3" filename. However this is not usually a problem
as you can specify archive and cabinet files with "8.3" files. Netscape Navigator
and Microsoft Internet Explorer usually find these files in preference to
the class files, and so the applet will run.
For example, the PHD Hi Spy Java applet has a main program file called HiSpy.class.
However, PHD supplies an archive file called hispy10.zip and a cabinet file called
hispy10.cab. The following code makes the applet run:
<APPLET CODE=HiSpy WIDTH=350 HEIGHT=300 ARCHIVE=hispy10.zip>
<PARAM NAME=cabbase VALUE="hispy10.cab">
...
</APPLET>
The UDF OSTA format allows you to write to a CD-R disk as if it were a normal drive.
However you have to "finalise" the disk for it to be readable on normal CD-ROM readers.
Even then, the user has to have the necessary UDF OSTA drivers.
This Unified Disk Format (UDF) format is for CD-ROMs and Digital Versatile Disk (DVD)
and was developed by the Optical Storage Technology Association (OSTA).
El Torito is a format for CD-ROMs which allows them to be used to boot computers, ie get their operating system from the CD-ROM rather than their local hard or floppy disk. The "El Torito — Bootable CD-ROM Format Specification Version 1.0" is published by IBM and Phoenix.
If your server dishes up "index.html" by default then this filename will not transfer well to a "8.3" disk. Perhaps provide a separate initial web file for your CD-ROM called "index.htm".
If subsidiary pages provide a link back to the entry page, then do not just
specify a link of "/" as this will not work on a CD-ROM. Instead hard-code
the default for your server, eg "default.htm". This will work online as well.
It's all relative
Your HTML pages on CD-ROM may be at any position in a user's file system
so make sure that all your HTML links are relative.
Eg in a file "content/list.htm" use a link "../software/browsers.htm"
rather than "/software/browsers.htm".
Remember to use forward slash characters, not PC backslashes.
You may well want other links on your CD-ROM to be absolute,
ie have the full address of your online web site.
For example, a "Latest News" link could point to
"http://www.product.com/latest.htm".
It is useful convention to highlight such absolute links away from
the CD-ROM with a small off-site icon image.
Navigation tools
Given that you want to publish information on CD-ROM, you probably have
a reasonably large number of web pages. It is a good idea to provide
additional means of navigating the pages.
The navigation tools range from simple menu link systems, through site maps and finally full text search engines.
Menus can be hard coded as HTML links, in a standard format and place on your web pages. JavaScript can make these change dynamically, eg providing two levels of menu within a small space.
For larger sites, a site map provides a hierarchical tree view of all the web
pages. An Index of keywords is often available. More than one map could be
provided.
PHD's Hi HelpIndex Java applet
runs well in small to medium sized CD-ROMs, as well as online sites.
It uses a static "index files" which have all the contents and index information;
no search of the web pages is needed.
PHD's Hi Lab Windows program can scan your existing web site
to make an initial index file; you can then easily edit it visually.
The Hi Jump applet provides navigation arrows on each page.
Full text search engines for CD-ROMs obviously must not be server based. It is best if they build up a database of all the words on a CD-ROM first rather than searching on the fly. You will usually have enough room for a reasonably large database on a CD-ROM. Ideally search tools should be able to index and display non-HTML documents, eg Acrobat pdf files, Word documents, etc.
PHD's Hi Spy Java applet provides a full text search facility for HTML CD-ROMs. The Hi Fashion Windows utility is used to scan the web pages and build the word database. You can then edit the word database easily. Hi Spy can select between different word databases and choose the most appropriate one for the user's language. Hi Spy screenshot
For more sophistication, check out CD-Web Publisher from Verity and WebCD from Fulcrum. These tools also provide full CD publishing facilities, including online updates to a CD if connected. Verity supports several viewer platforms, while Fulcrum needs Windows.
The above products have an initial cost and a licence charge per CD produced.
AutoPlay
In Windows 95, 98, NT and 2000, the CD-ROM can AutoPlay a program when the CD-ROM
is inserted into the computer.
Note that only NT/W2000 Power Users or Administrators can use AutoPlay.
Make sure that you provide instructions on how to use the CD-ROM "by hand"
as some people have AutoPlay turned off.
You simply provide a plain text file called AUTORUN.INF and simply put in:
[autorun] open = Setup.exe icon = Setup.exewhere Setup.exe can be any executable name (with parameters if necessary).
You can use the Windows start command to display a web page, eg:
[autorun] open=start index.htmHowever this may not work in some old command line shell DOS prompts. It also displays a brief annoying DOS box window as the start command is run.
PHD has written a tiny utility program ShellRun to overcome these problems. Get http://www.phdcc.com/download/shrun10.zip (or http://www.phdcc.com/download/ShellRun.exe). ShellRun's first parameter is the name of the document you want opened (no spaces). For example, to show index.htm, put this in AUTORUN.INF:
[autorun] open=ShellRun index.htmShellRun displays a small window in the top left hand corner of the screen as it opens the file. You can specify more text to have a different message displayed, eg:
[autorun] open=ShellRun index.htm Starting CD-ROM site...
Testing AutoPlay on FloppiesYou can test the AutoPlay facilities on a floppy disk.First, you must enable AutoPlay on floppies. Start the Registry Editor (Start+Run regedit) and search for NoDriveTypeAutoRun. Modify the entry from "95" to 91". (Or from "B5" to "B1" if you have disabled AutoPlay on CD-ROMs.) Do not forget to put this back again when you are finished. Now log off and log on again. You will have to do this after every change to the AUTORUN.INF file on a floppy. To test, open "My Computer" and double-click on the A: icon. Alternatively, right-click on the A: icon (or in Windows Explorer, right-click on the A:) to get the pop-up menu; select AutoPlay to run your program. If you have specified other AUTORUN options, see below, then these should be listed in the pop-up menu. |
This example show how to add two entries to the menu
(Read me - to display the README.TXT file in notepad, and
Software list - to show HTML file software.htm):
[AutoRun] shell\readme\command=notepad README.TXT shell\readme=Read &me shell\software\command=ShellRun software.htm shell\software=Software listAny verb string (without spaces) can appear after "shell\"; "readme" and "software" were used above.
Finally, AUTORUN.INF may have other sections for other NT/W2000 users,
ie MIPS [autorun.mips], DEC Alpha [autorun.alpha] and PowerPC [autorun.ppc].
The Microsoft CdCache utility (for Explorer 4) allows the CD-ROM to appear
as a part of a different web site; CdCache gets parameters from different
sections of AUTORUN.INF.
View on CD
Will your pages be viewable on the CD-ROM.
Or will they need to be installed onto the user's hard disk first?
For HTML CD-ROMs, it is usually straight forward to let users browse the CD-ROM directly. However it is often useful to provide an option to install the whole site on a local hard disk.
In some situations, you may need the HTML pages to be installed before they are
used. For example, if your pages have long file names but you opt to use
"8.3 format" file names on the CD-ROM,
then your install program will need to copy the files to a hard disk,
changing the file names as necessary.
Installing to Disk
As mentioned above, you may want to install something onto the user's local
hard disk.
A web site which has been copied to a user's hard disk may be updated
with new information.
Installation may simply be a case of copying the HTML files onto disk, but may involve changing the filenames.
Alternatively, you may have some software to install. For PCs there are several well known vendors of installation tools, eg InstallShield and Wise. They usually have comprehensive set up tools, possibly with script languages. They ensure that the files are copied, the registry updated and folders created. Make sure they have an Uninstall option.
For PCs, provide an AUTORUN.INF file (described above) which will AutoPlay when inserted into the CD-ROM drive. A nice touch would be to detect if your application is installed - if so, then do not run your set up program.
Some software suppliers have a single program file which contains all their files. When this program is run, it correctly installs itself on the user's hard disk. This approach allows the files to be compressed and kept together in one file, which can easily be downloaded by users.
So your HTML CD-ROM could firstly have all the web site laid out neatly on the CD-ROM. Then also provide a single executable which has the whole site (again); a user would run this file to install it on their local hard disk. This approach will make installing much quicker.
If you have a installable version of your site as a single executable, make sure it has a "8.3" filename. This makes it easy to include on other people's CD-ROMs or sites which might not support full filenames, eg magazine cover disks or shareware software archives. Include the major version number (or date) in the filename, eg PHD could call our CD-ROM executable "PHDMAR98.EXE". Do not forget to provide an uninstall program.
Alternatively, you could supply your site in zip or cab compressed formats
but this will be harder for users to install.
Apple Mac users prefer hqx format and Unix users the tar format.
Article Copyright © 1998,1999 Chris Cant, PHD Computer Consultants Ltd.