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I recently had to cut, on my laptop, some CDs of software to be loaded on several Solaris boxes at a remote site and found myself running up against incompatibilities between the Rock Ridge and Joliet extensions to the ISO 9660 International standard which defines a file system for CD ROMs. Specifically, I needed the files written to the CD in such a way that they would have the proper Unix long file names when mounted on the target systems. This would ensure that a scripted and heavily tested install procedure would work correctly.



Using two different tools for writing CDs on my laptop, however, I found myself looking at two very different file naming schemes, neither of which met my needs. In both cases, the files looked as if they had the proper names on the laptop itself, but they didn't maintain these names when mounted on one of the target systems.



In one case, the files took on DOS' 8.3 (short) file naming conventions in which file names were shortened to six characters followed by a tilde (~) and a digit to differentiate them. Mounted on the Solaris system, the files looked like this:

-r-xr-xr-x   1 root     sys      16292712 Mar 17 09:40 esbase~1.z
-r-xr-xr-x   1 root     sys      16294037 Mar 17 09:36 esbase~2.z

The same file names on the laptop itself (in a DOS command window) had looked proper:



esbase_mod_files.tar.Z

esbase_mod_conf.tar.Z



In the second case, the CD-writing application, used longer names but modified them in odd ways, so the same files ended up looking altogether different -- and they still did not meet my needs:



03/17/2006 09:40 AM 16,292,712 ESBASE_MOD_CONF_TAR.Z

03/17/2006 09:36 AM 16,294,037 ESBASE_MOD_FILES_TAR.Z



In an ideal cyberspace, incompatible file system extensions would not be complicating my life. In the less-than-ideal cyberspace in which we all work, however, there are at least workarounds for dealing with this kind of problem. The workaround that I found involved installing a couple new tools on my laptop.
Before we get to this solution, let's just briefly look at what was going on behind the scenes of my CD ROM creation problem.



ISO 9660 is one of the original CD ROM file systems. Most computer platforms today support it. For the most part, ISO 9660 adheres to the DOS 8.3 standard for file naming. From an ISO 9660 perspective, even files on a Rock Ridge CD ROM all have the old DOS-style 8.3 names.



What the Rock Ridge extension does, however, is add special files that allow these short names to be translated back into Unix style names, with Unix style permissions and Unix style directory structures.



Joliet follows a similar path, except that it adds Microsoft attributes, lacks some Unix attributes and is, unfortunately, incompatible with Rock Ridge. Both standards make use of ISO 9660, but differently.



Rock Ridge is the CD ROM file system standard that is used by most UNIX-based systems, including Linux and Solaris. Joliet is specifically used on computers running Windows. The Joliet file system is not specifically based upon ISO 9660, but an ISO 9660 volume must still be present.



To create a CD ROM on Windows with the extensions needed to work properly on my Solaris systems, therefore, I first had to create a file system with Rock Ridge extensions. After googling my way around the web, I found a copy of mkisofs (as in "make ISO file system") -- a command line tool that runs in my command prompt and allows me to create an ISO image that I can then write to a CD.



The command that I ran on my laptop looks something like this:

> mkisofs -r -o esbase.iso \delivery\ebase_files

where "esbase.iso" is the name of the ISO image I was creating and "\delivery\ebase_files" is the directory in which the files that I was adding to the image are located.

I then used a tool called "ISO Recorder" to write the ISO image to a CD ROM. This worked perfectly. Mounted on the Solaris system, the files list with the proper long names and the extract and install script was able to work with them as intended.

-r-xr-xr-x   1 root     root     16292712 Mar 17 09:40 esbase_mod_conf.tar.Z
-r-xr-xr-x   1 root     root     16294037 Mar 17 09:36 esbase_mod_files.tar.Z

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