From: tmatimar@empress.com (Ted M A Timar) Newsgroups: comp.unix.questions,comp.unix.shell,news.answers Subject: Frequently Asked Questions about Unix (6/7) [Biweekly posting] Date: 6 Nov 1992 06:01:27 GMT Expires: 4 Dec 1992 06:00:17 GMT Followup-To: comp.unix.questions Distribution: world Organization: Empress Software Lines: 698 Approved: news-answers-request@MIT.Edu Supersedes: NNTP-Posting-Host: pit-manager.mit.edu X-Last-Updated: 1992/10/21 Archive-name: unix-faq/part6 Version: $Id: part6,v 2.0 92/10/20 12:07:30 tmatimar Exp $ These seven articles contain the answers to some Frequently Asked Questions often seen in comp.unix.questions and comp.unix.shell. Please don't ask these questions again, they've been answered plenty of times already - and please don't flame someone just because they may not have read this particular posting. Thank you. These articles are divided approximately as follows: 1.*) General questions. 2.*) Relatively basic questions, likely to be asked by beginners. 3.*) Intermediate questions. 4.*) Advanced questions, likely to be asked by people who thought they already knew all of the answers. 5.*) Questions pertaining to the various shells, and the differences. 6.*) An overview of Unix variants. 7.*) An comparison of configuration management systems (RCS, SCCS). This article includes answers to: 6.1) Disclaimer and introduction. 6.2) A very brief look at Unix history. 6.3) Main Unix flavors. 6.4) Unix Standards. 6.5) Identifying your Unix flavor. 6.6) Brief notes on some well-known (commercial/PD) Unices. 6.7) Real-time Unices. 6.8) Unix glossary. 6.9) Acknowledgements. If you're looking for the answer to, say, question 6.5, and want to skip everything else, you can search ahead for the regular expression "^6.5)". While these are all legitimate questions, they seem to crop up in comp.unix.questions or comp.unix.shell on an annual basis, usually followed by plenty of replies (only some of which are correct) and then a period of griping about how the same questions keep coming up. You may also like to read the monthly article "Answers to Frequently Asked Questions" in the newsgroup "news.announce.newusers", which will tell you what "UNIX" stands for. With the variety of Unix systems in the world, it's hard to guarantee that these answers will work everywhere. Read your local manual pages before trying anything suggested here. If you have suggestions or corrections for any of these answers, please send them to to tmatimar@empress.com. 6.1) Disclaimer and introduction. From: "Pierre (P.) Lewis" Date: Sun, 11 Oct 1992 15:29:00 +0000 Version: 2.0 The following is offered with no guarantee as to accuracy or completeness. I have done what I can in the time available and it still is very much work in progress. I hope to keep improving this summary. Comments welcome: lew@bnr.ca. Acknowledgements at the end. First a short definition. By Unix we mean an operating system typically written in C, with a hierarchical file system, integration of file and device I/O, whose system call interface includes services such as fork(), pipe(), and whose user interface includes tools such as cc, troff, grep, awk, and a choice of shell. Note that UNIX is a registered trademark of USL (AT&T), but will be used here in its generic sense. Most Unices (the more common plural form) are derived more or less directly from AT&T code (some code from the first C version is presumably still left in most), but there are also clones (i.e. Unix-compatible systems with no AT&T code). In addition, there are also Unix-like environments (e.g. VOS) sitting on top of other OSs, and OSs inspired from Unix (yes, even DOS!). These are not covered here. Little on real-time Unices yet (although more is planned). Unix comes in an incredible variety of flavors. This is to a large extent due to availability of sources and the ease of porting and modifying Unix. Typically, a vendor of Unix will start with one basic flavor (see below), take ideas/code from the other major flavor, add and change many things, etc. This results in yet another new Unix flavor. Today, there are literally hundreds of Unices available, the closest thing to standard Unix being (by definition) System V. This answer was put together mostly from information on the net and email. Some specific sources are also mentioned in the appropriate sections. 6.2) A very brief look at Unix history. From: "Pierre (P.) Lewis" Date: Sun, 11 Oct 1992 15:29:00 +0000 Version: 2.0 Unix history goes back to 1969 and the famous "little-used PDP-7 in a corner" on which Ken Thompson, Dennis Ritchie (the R in K&R) and others started work on what was to become Unix. The name "Unix" was intended as a pun on Multics (and was written "Unics" at first -- UNiplexed Information and Computing System). For the first 10 years, Unix development was essentially confined to Bell Labs. These initial versions were labeled "Version n" or "Nth Edition" (of the manuals), and were for DEC's PDP-11 (16 bits) and later VAXen (32 bits). Some significant versions include: V1 (1971): 1st Unix version, in assembler on a PDP-11/20. Included file system, fork(), roff, ed. Was used as a text processing tool for preparation of patents. Pipe() appeared first in V2! V4 (1973): Rewritten in C, which is probably the most significant event in this OS's history: it means Unix can be ported to a new hardware in months, and changes are easy. The C language was originally designed for the Unix operating system, and hence there is a strong synergy between C and Unix. V6 (1975): First version of Unix widely available outside Bell Labs (esp. in universities). This was also the start of Unix diversity and popularity. 1.xBSD (PDP-11) was derived from this version. J. Lions published "A commentary on the Unix Operating System" based on V6. V7 (1979): For many, this is the "last true Unix", an "improvement over all preceding and following Unices" [Bourne]. It included full K&R C, uucp, Bourne shell. V7 was ported to the VAX as 32V. The V7 kernel was a mere 40 Kbytes! Here (for reference) the system calls of V7: _exit, access, acct, alarm, brk, chdir, chmod, chown, chroot, close, creat, dup, dup2, exec*, exit, fork, fstat, ftime, getegid, geteuid, getgid, getpid, getuid, gtty, indir, ioctl, kill, link, lock, lseek, mknod, mount, mpxcall, nice, open, pause, phys, pipe, pkoff, pkon, profil, ptrace, read, sbrk, setgid, setuid, signal, stat, stime, stty, sync, tell, time, times, umask, umount, unlink, utime, wait, write. These Vn versions were developed by the Computer Research Group (CRG) of Bell Labs. Another group, the Unix System Group (USG), was responsible for support. A third group at Bell Labs was also involved in Unix development, the Programmer's WorkBench (PWB), to which we owe, for example, sccs, named pipes and other important ideas. Both groups were merged into Unix System Development Lab in 1983. Work on Unix continued at Bell Labs in the 1980s. The V series was further developed by the CRG (Stroustrup mentions V10 in the 2nd edition of his book on C++), but we don't seem to hear much about this otherwise. The company now responsible for Unix (System V) is called Unix System Laboratories (USL) and is majority-owned by AT&T. But much happened to Unix outside AT&T, especially at Berkeley (where the other major flavor comes from). Vendors (esp. of workstations) also contributed much (e.g. Sun's NFS). The book "Life with Unix" by Don Libes and Sandy Ressler is fascinating reading for anyone interested in Unix, and covers a lot of the history, interactions, etc.. Much in the present section is summarized from this book. 6.3) Main Unix flavors. From: "Pierre (P.) Lewis" Date: Sun, 11 Oct 1992 15:29:00 +0000 Version: 2.0 Until recently, there were basically two main flavors of Unix: System V (five) from AT&T, and the Berkeley Software Distribution (BSD). SVR4 is essentially a merge of these two flavors. End '91, OSF/1 from the Open Software Foundation was released (as a direct competitor to System V) and may (future will tell) change this picture. The following lists the main releases and features of System V, BSD and OSF/1. System V from AT&T. Typical of Intel hardware. Most often ported Unix, typically with BSD enhancements (csh, job control, termcap, curses, vi, symbolic links). System V evolution is now overseen by Unix International (UI). UI members include AT&T, Sun, .... Newsgroup: comp.unix.sysv[23]86. Main releases: - System III (1982): first commercial Unix from AT&T - FIFOs (named pipes) (later?) - System V (1983): - IPC package (shm, msg, sem) - SVR2 (1984): - shell functions (sh) - SVID (System V Interface Definition) - SVR3 (1986) for ? platforms: - STREAMS (inspired by V8), poll(), TLI (network software) - RFS - shared libs - SVID 2 - demand paging (if hardware supports) - SVR3.2: - merge with Xenix (Intel 80386) - networking - SVR4 (1988), mainstream of Unix implementations, merge of System V, BSD, and SunOS. - From SVR3: sysadmin, terminal I/F, printer (from BSD?), RFS, STREAMS, uucp - From BSD: FFS, TCP/IP, sockets, select(), csh - From SunOS: NFS, OpenLook GUI, X11/NeWS, virtual memory subsystem with memory-mapped files, shared libraries (!= SVR3 ones?) - ksh - ANSI C - Internationalization (8-bit clean) - ABI (Application Binary Interface -- routines instead of traps) - POSIX, X/Open, SVID3 - SVR4.1 - async I/O (from SunOS?) - SVR4.2 (based on SVR4.1ES) - Veritas FS, ACLs - Dynamically loadable kernel modules - Future: - SVR4 MP (multiprocessor) - Use of Chorus microkernel? Berkeley Software Distribution (BSD). Typical of VAXen, RISCs, many workstations. More dynamic, research versions now than System V. BSD is responsible for much of the popularity of Unix. Most enhancements to Unix started here. The group responsible at UCB (University of California at Berkeley) is the Computer System Research Group (CSRG). They closed down in 1992. Newsgroup: comp.unix.bsd. Main releases: (much reorganized wrt dates and releases, hope it's converging) - 2.xBSD (1978) for PDP-11, still of significance? (2.11BSD was released in 1992!). - csh - 3BSD (1978): - virtual memory - 4.?BSD: - termcap, curses - vi - 4.0BSD (1980): - 4.1BSD (?): base of later AT&T CRG versions - job control - automatic kernel config - vfork() - 4.2BSD (1983): - TCP/IP, sockets, ethernet - UFS: long file names, symbolic links - new reliable signals (4.1 reliable signals now in SVR3) - select() - 4.3BSD (1986) for VAX, ?: - 4.3 Tahoe (1988): 4.3BSD with sources, support for Tahoe (32-bit supermini) - Fat FFS - New TCP algorithms - 4.3 Reno (1990) for VAX, Tahoe, HP 9000/300: - most of P1003.1 - NFS (from Sun) - MFS (memory file system) - OSI: TP4, CLNP, ISODE's FTAM, VT and X.500; SLIP - Kerberos - 4.4BSD (will we ever see it?) for HP 9000, Sparc, 386, DEC, Tahoe: - new FS organization, new process internals, new virtual memory based on Mach 2.5 - POSIX compatibility - OSI (based on ISODE), X.25 The Open Software Foundation (OSF) released its Unix called OSF/1 end of 1991. Still requires an SVR2 license. Compatible/compliant with SVID 2 (and 3 coming), POSIX, X/Open, etc.. OSF members include Apollo, Dec, HP, IBM, .... - OSF/1 (1991): - based on Mach 2.5 kernel - symmetric multiprocessing, parallelized kernel, threads - logical volumes, disk mirroring, UFS (native), S5 FS, NFS - enhanced security (B1 with some B2, B3; or C2), 4.3BSD admin - STREAMS, TLI/XTI, sockets - shared libs, dynamic loader (incl. kernel) - Motif GUI - Future: - OSF/1 MK (mikrokernel) based on Mach 3.0 This list of major flavors should probably also include Xenix which has been the basis for many ports. Derived from V7, S III and finally System V, it is similar externally but significantly changed internally (performance-tuned for micros). Two very good books describe the internals of the two main flavors. These are: - System V: "Design of the Unix Operating SYstem", M.J. Bach. - BSD: "Design and Implementation of the 4.3BSD Unix Operating System", Leffler, McKusick, Karels, Quaterman. For a good introduction to OSF/1 (not quite as technical as the previous two), see: "Guide to OSF/1, A Technical Synopsis", published by O'Reilly. On SunOS, "Virtual Memory Architecture in SunOS" and "Shared Libraries in SunOS" in Summer 1989 USENIX Proceedings. A good set of articles on where Unix is going is "Unix Variants" in the Apr 92 issue of Unix Review. Other good sources of information include the bsd-faq file, and many of the newsgroups mentioned in the text. 6.4) Unix Standards. From: "Pierre (P.) Lewis" Date: Sun, 11 Oct 1992 15:29:00 +0000 Version: 2.0 This section briefly describes the more important standards relevant to Unix. - IEEE: - 802.x (LAN) standards (LLC, ethernet, token ring, token bus) - POSIX (ISO 9945?): Portable Operating System I/F (Unix, VMS and OS/2!) (only ? have been finalized at this point) - 1003.1: library procedures (mostly system calls) -- roughly V7 except for signals and terminal I/F (1990) - 1003.2: shell and utilities - 1003.3: test methods and conformance - 1003.4: real-time: binary semaphores, process memory locking, memory-mapped files, shared memory, priority scheduling, real-time signals, clocks and timers, IPC message passing, synchronized I/O, asynchronous I/O, real-time files - 1003.5: Ada language bindings - 1003.6: security - 1003.7: system admin (incl. printing) - 1003.8: transparent file access - 1003.9: FORTRAN language bindings - 1003.10: super computing - 1003.12: protocol-independent I/Fs - 1003.13: real-time profiles - 1003.15: supercomputing batch I/Fs - 1003.16: C-language bindings (?) - 1003.17: directory services - 1003.19: FORTRAN 90 language bindings - X/Open (consortium of vendors): - X/Open Portability Guides (XPGn): - XPG2 (1987), strong SV influence Vol 1: commands and utilities Vol 2: system calls and libraries Vol 3: terminal I/F (curses, termio), IPC (SV), internationalization Vol 4: programming languages (C, COBOL!) Vol 5: data management (ISAM, SQL) - XPG3 adds: ? - XOM series of interfaces: - XOM (X/Open Object Management) generic I/F mechanisms for following - XDS (X/Open Directory Service) - XMH (X/Open Mail ??) - XCM (X/Open Consolidated Management) (not yet approved?) - AT&T - System V Interface Definition (SVID) - SVID1 (1985, SVR2) Vol 1: system calls and libraries (similar to XPG2.1) - SVID2 (1986, SVR3) Vol 1: system calls and libraries (base, kernel extensions) Vol 2: commands and utilities (base, advanced, admin, software development), terminal I/F Vol 3: terminal I/F (again), STREAMS and TLI, RFS - SVID3 (19??, SVR4) adds Vol 4: ?? &c - APIs - Transport Library Interface (TLI) - ACSE/Presentation Library Interface (APLI) 6.5) Identifying your Unix flavor. From: "Pierre (P.) Lewis" Date: Sun, 11 Oct 1992 15:29:00 +0000 Version: 2.0 This section lists a number of things you can look at in attempting to identify the base flavor of your Unix. Given the significant exchange of code and ideas between the various flavors and the many changes made by vendors, any statement such as "this Unix is an SVR2" is at best a statistical statement (except for some SVRn ports). Also many Unices offer most of both worlds (either mixed as in SunOS or strictly separated as in Apollo?). So this section is perhaps not very useful... The list of features in previous sections can also help. For example, if a system has a poll(2) but no select(2), it is highly probable that it is derived from SVR3. Also the name of the OS can provide a clue, as well as the logon message (e.g. SGI's "Irix SVR3.3.2") or the output of "uname -a" command. Available commands can also provide hints but this is probably less reliable than kernel features. For example, the type of terminal Feature Typical in SVRx Typical in xBSD kernel name /unix /vmunix terminal init /etc/inittab /etc/ttys (only getty to 4.3) boot init /etc/rc.d directories /etc/rc.* files mounted FSs /etc/mnttab /etc/mtab usual shell sh, ksh csh, #! hack native FS S5 (blk: 512-2K) UFS (blk: 4K-8K) file names <= 14 bytes file names < 255 bytes groups need newgrp(1) automatic membership SVR4: multiple groups print subsystem lp, lpstat, cancel lpr, lpq, lprm (lpd daemon) ?? terminal control termio, terminfo, termios (sgtty before 4.3reno) SVR4: termios (POSIX) termcap job control >= SVR4 yes ps command ps -ef ps -aux string fcns memset, memcpy bzero, bcopy process mapping /proc (SVR4) 6.6) Brief notes on some well-known (commercial/PD) Unices. From: "Pierre (P.) Lewis" Date: Sun, 11 Oct 1992 15:29:00 +0000 Version: 2.0 (I am not at all satisfied with this section, unfortunately I have neither the time nor the documents to make it much better (wrt contents). Should only list Unices known by a reasonably wide audience. Small and non-US Unices welcome, e.g. Eurix. In need of reformatting) This section lists (in alphabetical order) some of the better known Unices along with a brief description of their nature. AIX: IBM's Unix, based on SVR2 (later up to SVR3.2?) with varying degrees of BSD extensions, for various hardwares. Proprietary system admin (SMIT). Both 850 and Latin-1 CPs. Quite different from most Unices and among themselves. Newsgroup: comp.unix.aix. - 1.x (for 386 PS/2) - 2.x (for PC RTs) - 3.x (for RS/6000), paging kernel, logical volume manager, i18n; 3.2 adds TLI/STREAMS - there is also a version for S/370 mainframes (as task under VM) Was to have been base for OSF/1 until Mach was chosen instead. AOS (IBM): 4.3BSD port to IBM PC RT (for educational institutes). Don't confuse with DG's proprietary OS of same name. Arix: SV A/UX (Apple): SV with Berkeley enhancements, NFS, Mac GUI. System 6 (later System 7) runs as guest of A/UX (opposite of MachTen). Newsgroup: comp.unix.aux. - 2.0: SVR2 with 4.2BSD, system 6 Mac applications. - 3.0 (1992): SVR2.2 with 4.3BSD, system 7 applications. BOS for Bull's DPX/2 (680x0) - V1 (1990): SVR3 with BSD extensions (FFS, select, sockets), symmetric MP, X11R3 - V2 (1991): adds job control, disk mirroring, C2 security, DCE extensions 386BSD: Jolitz's port of Net2 software. Posix, 32-bit, still in alpha. BSD/386 (80386): from BSDI, with source (augmented Net2 software) Newsgroup: comp.unix.bsd. Chorus/MiXV: Unix SVR3.2 (SVR4) over Chorus nucleus, ABI/BCS. Coherent (80286): Unix clone compatible with V7, some SVR2 (IPC). V4.0 is 32-bit. Newsgroup: comp.os.coherent Consensys: SVR4 CTIX: SV-based, from Convergent D-NIX: SV DomainIX (Apollo): dual Unix over Apollo Domain operating system DomainOS (Apollo): BSD 4.2? with System V? (strict differentiation?) - 10.x DVIX (NT's DVS): SVR2 DYNIX (Sequent): 4.2BSD-based DYNIX/PTX: SVR3-based Esix (80386): pure SVR4, X11, OpenLook (NeWS), Xview Eurix (80?86): SVR3.2 (german?) FTX: Stratus fault-tolerant OS (68K or i860-i960 hardware) GNU Hurd (?): vaporware from the Free Software Foundation (FSF): Unix emulator over Mach 3.0 kernel. Many GNU tools are very popular (emacs) and used in the PD Unices. HP-UX (HP): old from S III (SVRx), now SVR2 (4.2BSD?) with SV utilities (they have trouble making up their minds). - 6.5: SVR2 - 7.0: SVR3.2, symlinks - 7.5 - 8.0: BSD based? for HP-9000 CISC (300/400) and RISC (800/700) Interactive SVR3.2 (80x86): pure SVR3. Interactive has been bought by Sun; will their system survive Solaris? Idris: first Unix clone by Whitesmith. - 4D Irix (SGI): SVR3.2, much BSD. Newsgroup: comp.sys.sgi. Linux (80386): PD Unix, SVish. Available with sources. Newsgroup: comp.os.linux MachTen, Tenon Intersystems: runs as a guest of System 6, no memory protection, 4.3BSD environment with TCP, NFS. MacMach (Mac II): 4.3BSD over Mach 3.0 microkernel, X11, Motif, GNU software, sources, experimental System 7 as Mach task. Mach386: from Mt Xinu. Based on Mach 2.5, with 4.3BSD-Tahoe enhancements. Also 2.6 MSD (Mach Source Distribution). Microport (80x86): pure SVR4, X11, OpenLook GUI Minix (80x86, Atari, Amiga, Mac): Unix clone compatible with V7. Sold with sources. Being POSIXified (sp?). Newsgroup: comp.os.minix. MipsOS: SVish (RISC/OS, now dropped, was BSDish) more/BSD (VAX, HP 9000/300): Mt Xinu's Unix, based on 4.3BSD-Tahoe. Newsgroup: comp.os.xinu? Net/2 tape (from Berkeley, 1991): BSD Unix, essentially compatible with 4.3BSD, includes only sources free of AT&T code, no low-level code. See 386BSD and BSD/386 above. NextStep (Next): BSD over Mach kernel, own GUI. 386 version coming? - 1.0 NEWS-OS (Sony) - 3.2 OSF/1 (DEC): DEC's port of OSF/1 PC-IX (IBM 8086): SV SCO Xenix (80x86): SCO Unix (80x86): SVR3.2 Solaris (Sparc, 80386): - 1.0: essentially same as SunOS 4.1.1, with OpenWindows 2.0 and DeskSet utilities. - 1.0.1: SunOS 4.1.2 with multiprocessing (kernel not multithreaded); not for 386 - 2.0: will be based on SVR4 (and have symmetric MP), will include support for 386; with OpenWindows 3.0 (X11R4), DeskSet, ONC, NIS. Compilers unbundled! SunOS (680x0, Sparc, i386): based on 4.3BSD, includes much from System V. Main Sun achievements: NFS (1984), SunView (1985), NeWS (1986, postscript imaging, now in OpenWindows), OpenLook GUI standard, OpenWindows (NeWS, X11, SunView!). Newsgroup: comp.sys.sun.*. - 3.x: SV IPC package, FIFOs - 4.0.3: lightweight processes, new virtual mem, shared libs - 4.1: STREAMS & TLI, 8-bit clean?, async I/O, ms-dos file system (continues as Solaris -- see above). UHC (80x86): pure SVR4, X11, Motif Ultrix (DEC): based on 4.2BSD with much of 4.3. Newsgroup: comp.unix.ultrix. - 3.1, 4.0 UNICOS (Cray): Newsgroup: comp.unix.cray - 5.x, 6,x, 7.0 UTEK (Tektronix) - 4.0 Xenix (80x86): 1st Unix on Intel hardware, based on SVR2 (previously on S III and even V7). Newsgroup: comp.unix.xenix. 3B1 (680x0): SV-based, done by Convergent for AT&T. Newsgroup: comp.sys.3b1. 6.7) Real-time Unices. From: "Pierre (P.) Lewis" Date: Sun, 11 Oct 1992 15:29:00 +0000 Version: 2.0 This information is fragmentary. I doubt all of following are Unices -- input is welcome. RTU (Concurrent), for 68K boxes Stellix (Stardent); it's Unix, but is it real-time? Velocity (Ready Systems): VxWorks (Wind River Systems): BSDish, no termcap. Newsgroup: comp.os.vxworks. pSOS?? 6.8) Unix glossary. From: "Pierre (P.) Lewis" Date: Sun, 11 Oct 1992 15:29:00 +0000 Version: 2.0 This section provides short definitions of various concepts and components of (or related to) Unix systems. Chorus: message-passing microkernel, may form basis for a future release of SV. Chorus already have SVR4 running on top (binary-compatible). DCE (Distributed Computing Environment, from OSF): Includes RPC (Apollo's NCS), directory service (local based on DNS, global on X.500), time, security, and threads services, DFS (distrib. file system), .... OS-independent. DME (Distributed Management Environment, from OSF): future. FFS (Fast File System): alias for UFS (BSD name) Mach: modern kernels from CMU (Carnegie Mellon University) on which many Unices and other OSs are based (e.g. OSF/1, MacMach, ...): - 2.5: monolithic kernel with 4.2BSD - 3.0: microkernel with BSD Unix server in user space (and other OSs, e.g. MS-DOS) Newsgroup: comp.os.mach MFS: Memory File System NFS (Network File System): contributed by Sun to BSD, stateless server ONC (Open Network Computing): from Sun(?), includes RPC, name service (NIS aka YP), NFS, ... (found in many Unices, other OSs). RFS (Remote File System): SV, stateful server, incompatible with NFS RPC (Remote Procedure Call): high-level IPC (inter-process communication) mechanism. Two flavors. - ONC: Over TCP or UDP (later OSI), uses XDR to encode data. - DCE: has a different RPC mechanism (based on Apollo's NCS) S5 FS: System V's native file system, blocks 512 to 2K. sockets: BSD interface mechanism to networks (compare TLI). STREAMS: a message-passing kernel mechanism, initially in SVR3, which provides a very good interface for protocol development. TLI (Transport Library Interface): SV's interface to transport services (TCP, OSI). UI has also defined an APLI (ACSE/Presentation Library Interface) UFS (?): BSD's native file system, blocks 4K to 8K, cylinder groups, fragments. XTI (X/Open Transport Interface): TLI with enhancements 6.9) Acknowledgements. From: "Pierre (P.) Lewis" Date: Sun, 11 Oct 1992 15:29:00 +0000 Version: 2.0 (in addition to references): pat@bnr.ca, guy@auspex.com, pen@lysator.liu.se, mikes@ingres.com, mjd@saul.cis.upenn.edu, root%candle.uucp@ls.com, ee@atbull.bull.co.at, Aaron_Dailey@stortek.com. Many thanks!