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- From: gnu@hoptoad.UUCP (John Gilmore)
-
- In article <8128@ut-sally.UUCP>, akre@cuuxb.uucp (Mike Akre) writes:
- > Find knows how to not cross mount points in System V Release 3.0 and later.
- > It has a new option "-mount" that will restrict find's searching to the
- > filesystem containing the directory specified.
-
- SunOS 3.2 has a similar option, called "-xdev"; it says not to cross into
- a different device than the one on which the filename argument resides.
- As far as I can see, the two are the same.
-
- Ted Nolan (ted@usceast.uucp) posted diffs to Unix tar to add a "T"
- option to read filenames from standard input. However, his changes
- only worked for creating archives, not for reading from them. His
- changes were in net.sources posted 17 July 1984, as an "ed" script
- for editing 4.2BSD tar.c. I can provide copies if anybody wants 'em.
- I also generated a context diff from this and can provide that.
-
- It is true that my PD tar can read a list of filenames from standard
- input, for both creating and reading archives. It can also deal with a
- large list of names to extract even on a small memory system, by giving
- it another option letter indicating that the list on stdin is sorted to
- match the tape.
-
- I think that the argument boils down to:
-
- * Neither tar nor cpio is perfect for what we want.
-
- * People like cpio's user interface better.
-
- * Tar's format on the tape is more portable.
-
- As a standards effort, we can't just create a new "portable" format
- which is not portable to all the old Unix systems. If we claim the
- standard format is "cpio" or "tar" format, the old cpio or tar should
- be able to read it. All the suggestions for improving cpio format (Andy
- Tannenbaum's are a good example) ignore interchange with older systems.
- If we decide on a format which neither tar nor cpio, as they now stand,
- can read, let's invent a new name for the format and the command (posio,
- for portable standard I/O? That sounds too much like stdio though.
- Posar?).
-
- Personally I think what matters most is the interchange format, not the
- user interface; this is why I favor tar. The user or system implementer
- can always provide a better, or additional, user interface but they
- are stuck with the interchange format.
-
- As I recall, the draft I saw standardized the interchange format but
- specifically did not standardize the command used to generate that
- format. How would people feel about a compromise wherein a new option
- added to "cpio" would cause it to generate or read POSIX interchange tapes,
- which might happen to have a format compatible with V7 tar? Vendors
- could make this option the default if desired, requiring the user to
- specify an option to write binary or ascii cpio tapes. When reading,
- it could figure out the format of a tape without user intervention.
-
- Volume-Number: Volume 11, Number 36
-
-