sun microsystems Systems Architecture Committee _________________________________________________________________ Subject: /proc file system Submitted by: Roger A. Faulkner File: psarc/1991/001/opinion.ms Date: February 27th, 1991 Committee: Rob G., Graham H., Jarrett R., Bill S., Glenn Skinner, Rangaswamy V., Steve E. (abstention) 1. Summary The submission proposes extensions and changes to the UNIX- System V Release 4 (SVR4) /proc file system interface. 2. Decision & Precedence Information The proposal is accepted with modifications as specified in Appendix A. The deliverable, as modified, is classified as a minor change. The following projects must be delivered prior to this one: - SVR4 MT kernel implementation 3. Opinion The proposal is primarily a faithful implementation of the interfaces provided in the AT&T SVR4 product. Where it differs is in extensions to support a variety of MT-related concepts and in changes relative to the specification of the SVR4 product that purport to improve the interface either through greater generality or by clarification. The committee finds the extensions acceptable. However, the committee was unable to accept the changes that deleted portions of the specifications of the SVR4 product. In debating this, the committee recognizes the following as _________________________ - UNIX is a registered trademark of The Open Group in the U.S. and other countries. psarc/1991/001 Copyright 1991 Sun Microsystems, Inc. - 2 - guidelines that have the strength of rules: o The SVID, ABI, and related ``public specifications for portability'' are inviolable. o Where interfaces are reflected not in any of these specifications, but instead in those of the SVR4 product implementation, it remains our intent to follow them. o Exceptions can be granted to the latter more than the former in the face of compelling arguments for improvement. o These guidelines are limited in scope to SVR4, and need not necessarily be assumed for future AT&T products. However, where an interface is con- sidered to be ``owned'' by a product implementor such as AT&T, it is more likely that these guide- lines would be extended to future versions. ``Owner'' in this context means ``the definitive representative of `what to do' with this interface in the minds of the UNIX community.'' The real issue is the portability of programs among imple- mentations - and in the absence of an authorita- tive independent specification the ``standard'' is viewed to be the ``owner's'' defining implementa- tion. The deleted portions of the SVR4 product in this specifica- tion can not be justified by compelling argument. The com- mittee believes that a compelling argument could have been made that the SVR4 product should not have been built with the interfaces the proposal would delete, but are not suffi- ciently compelling given that SVR4 includes them. 4. Minority Opinion(s) None. The majority opinion is unanimous. 5. Advisory Information None. 6. Appendices 6.1. Appendix A: Technical Changes Required 1. The standard SVR4 ioctl operations that manipulate the PR_FORK and PR_RLC mode flags are to be restored to the specification (the proposal deletes them.) It is acceptable to document that their use is deprecated in favor of the proposal's psarc/1991/001 Copyright 1991 Sun Microsystems, Inc. - 3 - more general PIOCSET and PIOCRESET operations. 2. The proposal deletes the flags MA_BREAK and MA_STACK from the flags returned on a PIOCMAP operation. These are to be restored to the specification, although it is acceptable to docu- ment their use as deprecated. 6.2. Appendix B: Technical Changes Advised None. 6.3. Appendix C: Reference Material 1. ``/proc - process file system'', Roger A. Faulkner, February 15th 1991, File: psarc/1991/001/NNNNproc.4. psarc/1991/001 Copyright 1991 Sun Microsystems, Inc.