| Make those coasters... |
Here are the crucial points to consider:
PracticalitiesYou will need a CD-ROM writer to build your test CD-ROMs.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. IDE writers may be more prone to errors. Slow PCs and unbranded disks may similarly result in duff disks. Basic CD-R disks only cost about a pound, while CD-RW disks are a tenner or so. CDs give you 500 to 600 MB of space. Note that there is an overhead of several MB each time you write. CD-R disks may only be writeable 100 times. For small quantities with not too much data, you can burn each CD yourselves, 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 £400 glass master charge, costs soon come tumbling down: eg 1000 CDs costs about 60p each. You will need colour separated artwork. Don't forget a jewel case (15p) or plastic wallet (9p), and the printed inserts (say 40p). Expect the courier in 2 weeks!
Double and triple check your release CD-ROMs. |
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.
Target Audience Capabilities
You must think what computers your target audience will be running.
In some cases you may be certain that your users will be running Windows 95 (or NT 4) 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.
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.
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.
However the Rockridge format does allow longer 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. I believe that Young Minds software can install from a "8.3" CD while restoring the full filenames.
You can be nice to Apple Mac users and produce a dual format CD, ie where the Apple resource forks are provided.
Unified Disk Format (UDF) format for CD-ROMs and Digital Versatile Disk (DVD).
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.
For Windows programs, having an executable (EXE) file is best. Simply running this file brings up the installation program. Do not forget to provide an uninstall program.
Other suitable formats for compressed distribution are zip and cab formats,
hqx for Apple Macs and tar for Unix.
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. It uses a static "index files"
which have all the contents and index information; no search of the web pages
is needed. Its 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 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.
AutoPlay
In Windows 95 and NT, the CD-ROM can AutoPlay a program when the CD-ROM
is inserted into the computer.
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.
As standard, you cannot specify an HTML file name to open. However PHD has written a tiny utility program ShellRun to do this job. 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 AutoPlayYou 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". (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. |
The shell command lets you specify one or more entries in the pop-up menu when the user right-clicks on the CD-ROM icon. The shell entries override the open command.
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 listThe "readme" and "software" strings can be any text (without spaces). The first line specifies the command to run, while the next specifies the text that appears in the menu. As usual, an ampersand character (&) precedes the short-cut menu key.
Finally, AUTORUN.INF may have other sections for other NT users,
ie MIPS, DEC Alpha and PowerPC.
Installing to Disk
As mentioned above, you may want to install something onto the user's local
hard disk.
This 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.