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- From: jsq@usenix.uucp (John Quarterman)
-
- cpio format objections Page 1 of 2 IEEE P1003.1 N.117
- 24 August 1987
-
- John S. Quarterman
-
- Institutional Representative from USENIX
- usenix!jsq
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- Secretary, IEEE Standards Board
- Attention: P1003 Working Group
- 345 East 47th St.
- New York, NY 10017
-
- Cc: 1003.1 Technical Reviewers
- for Section 10: for Rationale:
- Stephen Dum Lorraine Kevra Hal Jespersen
- tektronix!athena!steved attunix!kevra ucbvax!unisoft!hlj
-
- The USENIX Association ballots no on the test balloting of
- IEEE 1003.1 Draft 11, objecting to the proposed inclusion of
- cpio format, for the following reasons:
-
- 1. The need for extensions for symbolic links and
- contiguous files has not been properly addressed.
- Although three type codes are reserved, no indication
- is given of what they should be used for. This does
- not promote the need for those who implement such
- extensions to implement them the same way. It is true
- that the text of the standard cannot refer to symbolic
- links or high performance files, because they are not
- defined in the standard. But the USTAR format
- indicates the use of its codes for those extensions
- both by the name of the code given in the standard,
- and by explicit recommendations in the Rationale. The
- cpio proposal does neither.
-
- 2. The need for implementation-specific extensions that
- do not conflict with present or future standard file
- types has not been addressed. The USTAR format
- addresses the problem by reserving 26 codes for
- implementations to use as they see fit. The cpio
- proposal does not address the problem at all.
-
- 3. The c_ino field of the cpio format is derived from the
- UNIX inode number. Many implementations of cpio use
- only 16 bits for this number, and thus cannot properly
- resolve links noted in cpio archives that use more
- bits for this number. Tar and USTAR formats do not
- have this problem, because they do not use a number
- like this to resolve links. While some USTAR file
- types cannot be read by historical tar
- implementations, an error will usually be produced.
- This cpio problem will cause silent creation of
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- cpio format objections Page 2 of 2 IEEE P1003.1 N.117
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- erroneous links, which is worse.
-
- 4. There are few, if any, distributions of UNIX systems
- that do not include the tar program, which is
- compatible with the POSIX USTAR format. There are
- many UNIX systems that do not include cpio.
-
- 5. There is a public domain implementation of USTAR
- format. There is no public domain implementation of
- cpio format, with or without extensions.
-
- There should be one data interchange/archive format in IEEE
- 1003.1.
-
- + The proposed cpio format is technically inferior to
- USTAR format.
-
- + The program that cpio format is based on is not as
- widely available as the one that USTAR format is based
- on, and the same is true of the proposed cpio format
- and of USTAR format, respectively.
-
- Therefore, the one format in the standard should be USTAR.
-
- Specific action: deny the cpio format proposal, and do not
- include in the standard any references to that format or to
- cpio.
-
- Thank you,
-
-
-
- John S. Quarterman
- Texas Internet Consulting
- 701 Brazos, Suite 500
- Austin, TX 78701-3243
- 512-320-9031
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- Volume-Number: Volume 12, Number 21
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