Perry E. Metzger scripsit:
>
> [EMAIL PROTECTED] says:
> > Not even the standard io library on my system (IRIX 4) gives sparse files,
> > either local or via NFS. I fear that that is a nice feature whose life has
> > expired.
>
> You are mistaken. However, this is not an AFS issue.
Perry shoots from the hip and as usual straight into his foot.
There are certainly no sparse files creatable with fseek and friends on IRIX 4.
Then, the concept of sparse files implies knowledge of the physical disk
structure. NFS (to some degree) and AFS present to the user a logical
abstraction from the file systems as a collection of disk blocks; files are
now named byte streams. And yes, this IS an AFS issue.
In AFS the file is maintained by a proxy (the cache controller) on behalf
of the actual server, and presented to the user as required. This involves
a copy of the file (or a chunk of it) through the network.
Already on plain unix file systems, operations like tar, cat, tail,
compress (to name a few) do not preserve sparsity, virtually the only one
that does is cp, because it is written to access disk blocks for
efficiency, and "true" mv, for obvious reasons.
Therefore I fear sparsity will have to bite the dust sooner or later,
as logical abstractions do not mix too well with physical concepts.
Thomas
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