Re: Tiger OS X 10.4 Big Fortran Problem

Ron Shepard wrote:
In article <d5d5ml$5ff$1@xxxxxxxxxxxxxxxxxxxxxxxxxx>,
 Dave Seaman <dseaman@xxxxxxxxxxxx> wrote:

That's true on most Unix systems, but the OP is asking about Mac
OS X Tiger, which has a case-insensitive file system.

Just to be clear, this is not a feature of the operating system, it is a feature of the HFS+ file system. If you are using a different filesystem, e.g. ufs or an nfs-mounted remote filesystem, then OS X behaves the same as any other unix/posix machine. I remember reading rumors a few months ago that HFS+ was going to have an option to be case sensitive under 10.4, but I haven't heard anything about that in the past few days since the release, so I guess it didn't happen. I've also heard rumors that support for some of the popular linux filesystems, such as ext3, was going to appear in 10.4, presumably to allow hard drives to be used without reformatting on several machines or in duel boot situations; if and when this occurs, then OS X will probably act the same as any other unix OS on these filesystems.

This feature of OS X has always been a little confusing to me. It does not act the way that VAX/VMS worked -- with a VAX, which also had a case-insensitive file system, the files always "appeared" to be in upper case. You could access them with lower or mixed case, but you always "knew" that they were sitting there on the disk with their folded uppercase names. OS X and HFS+ doesn't do it the same way. For example, if you have a fortran file file.f in one directory, and a file.F in another directory, then the latter will be compiled with the preprocessor and the first one will not; that is, the compiler can tell the difference in the file names and act accordingly. In this sense, upper and lower case are not treated the same with OS X. The limitation is that you cannot have both file.f and file.F in the same directory, and if you try to move or copy the second file into a directory with the first, it will overwrite the first file.

The buzzwords are that Mac HFS+ is case retentive but case insensitive. So you get it back the way you spelt it but all other variations on case will match the same name. I have been seeing somethings about the case sensitive extension to HFS+ which can be used for data volumes but not the boot volume. I did not pay close attention as it seems to be directed at the server version, or some other variant which does not apply to me.

Being case retentive but case insensitive strikes me as a sensible
mode as it leaves the names visually distinctive without the bother of having Test, test and TEST all be distinct. This confusion is what I
have learned to call "Failing the telephone test" as it makes life
difficult to discuss names over the telephone. F90 passes the
telephone test.

Being case retentive but case insensitive also shows up in some of
the Unix emulators for Windows. MKS being the first example to come
to mind.

$.02 -Ron Shepard

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