jsq@usenix.uucp (John Quarterman) (08/25/87)
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 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 cpio format objections Page 2 of 2 IEEE P1003.1 N.117 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 Volume-Number: Volume 12, NIt's, ste