unix file system

[Ihnat]

Jon Campbell of Digital Equipment Corp. recently posted a problem
statement/proposal concerning the Unix filesystem, particularly addressing
the problems encountered by such utilities as FORTRAN and ANSI tape label
requirements.  His conclusion was that there needs to be an extension to
the Unix filesystem scheme, allowing such information to be optionally
available to needful users.

The problems he quotes are, indeed, real; as real as the need for good
database support in Unix.  The issue I wish everyone to consider is that
*any* specialized support of this type must never go in the kernel!

I well remember struggling through the incredible source listings of the
Honeywell Level 6 Gcos operating system.  They, too, started out to support
what appeared to be a reasonable subset of accepted typed files--ISAM,
KIDA, etc.  In the end, the operating system grew to the point that a listing
set stood 3 feet high; much of that, support for various file types.  

Worse, even if an installation didn't ever intend to use these capabilities,
machine resources were dedicated in the 'kernel' to allow the filesystem
to recognize and process them, regardless.

One of the big plusses of Unix was moving items that weren't required out
of the kernel.  If it isn't involved with managing shared and/or critical
resources, it doesn't belong in the kernel.  Database file management should
be the realm of a separate, although standard, package--and recognition
and support of specialized file formats such as those expected by FORTRAN
or programs that must read/write ANSI tapes.  Consider also that, whether
optionally used or not, such extensions must be validated by 'fsck' and
its ilk, thus complicating system maintenance and improving the liklihood
of filesystem corruption.  

I most emphatically agree that some standardized means of providing such
information would be desirable;  possibly a set of library routines and
maintenance programs.  But don't clutter the kernel with this; we made
significant strides in isolating functionality and improving modularity
when the Unix 'toolchest' approach gained favor; let's PLEASE not backslide!


-- 
	Dave Ihnat
	Analysts International Corporation
	(312) 882-4673
	ihnp4!aicchi!ignatz