November 9, 1977 KNOWN SYSTEM DEPENDENCIES / MAGIC NAMES IN EX-1.1 Globally: 1. Needs a printf which prints through putchar. 2. Wants the data bases described in SETUP. 3. Needs a large amount of core; separate i/d preferred. 4. Needs a version 7 C compiler. 5. Assumes (in the library routines and the way it deals with ttyn e.g. for the visualmessage option) that teletype names are single characters, and that /etc/utmp is indexed by this character. (More on this below.) --------------------------------------------- In the HEADERS: ex.h Defines ECHO and RAW for stty. Defines TTYNAM which is initialized in ex_tty.c and there assumes that single char teletype names are used. Note that ex does not catch the TERMINATE signal of version 7 UNIX... it should be defined here. ex_glob.h The definitions here limit the argument list size possible with the next command. This does not limit the size of entry argument list however... if invoked with a longer list that is ok (although it has never been tested of course!) ex_io.h The basic stat buffer structure is assumed here. Also the error codes for errno from system error returns on i/o are defined here... if you have more error codes you should add them... ex does not use "perror" because this way puts the messages in the string message file saving space. ex_vis.h The definitions of TUBELINES, TUBECOLS, and TUBESIZE here limit the kinds of terminals on which open and visual are possible. The areas are allocated, with fixed size, on the stack at entry to the routines in exo.c and exv.c. Variable sized screens would be possible if you added an assembly language intermediary here, or you can make these numbers larger, at the expense of allocating these larger buffers on terminals with small screens. --- CODE files: ex.c /erpath =+ 9/ Assumes that the error path contains a prefix like "/usr/lib" so that adding 9 bytes will give the last portion of the error file name for testing "a.out". /== 'd'/ Here derive the properties of "edit". /signal/ New caught signals should be added here, notably the signal TERMINATE for a version 7 system. ex_ca.c To add a cursor addressible terminal you must add it to the routine canCA and change cgoto to return a string. All terminals which are to be added must have their properties recorded in /etc/ttycap. ex_glob.c This glob routine supports constructs in all portions of path names, e.g. "/*/bill/a.out"; it also interprets trailing slashes as forcing a directory match - eg "*/" matches all subdirectory names. This corresponds to the glob which is glob2.c in ../s6 and also the glob built into ../ashell. ex_tty.c This routine assumes the version 6 structure of teletype names in its handling of TTYNAM. This can be easily changed by forming the value of TTYNAM in a slightly different way. ex_io.c The routine ioerror embodies the strings from "perror" which are related to input/output. These should be added to or changed as appropriate to your system. Perror is not used because it is desired to have the error messages in the string message file (this saves ~~ 200 bytes per editor user in the swap image.) ex_put.c Note the routine "setcol" which fixes UNIX's notion of the tab column position after a cursor addressing sequence on an ADM-3A. This is hard, in general. If you wish to perform a similar fix for your terminals this is the place to do it. ex_recover.c The routines here assume that you have installed the exrecover and expreserve routines from ../exrecover, and that when the system crashes you run expreserve in /etc/rc to save the stuff from /tmp so that people can continue where they left off. If this is not true, no harm is done... as long as you don't ever crash! ex_set.c Note that the default directory and shell are initialized here. ex_tty.c Here the capabilities of the terminal which interest us are extracted. These are used by the print routines in ex_put.c, and more exten- sively by the visual and open mode routines. Currently, we are running visual on ADM-3A's (its native terminal) and also on HP2645's. For the latter, the editor makes use only of the clear to end-of-line operation. I have not put in the use of the add and delete line operations (although they are read here into AL and DL). If you have a number of intelligent terminals you may wish to try to add the intelligent terminal driving to visual... it is not hard. I have not done it since we have only 2 HP2645's and both are at 9600 baud where it matters little if it knows about the intelligence. The routines most likely to be changed in such an addition are all in the file ex_vadjust.c... they are mentioned below. ex_unix.c It is here assumed that the shell understands the option "-c", and also the option "-i" to give a login type shell. Both of the shells from Berkeley, and also the Version 7 shell from Bell have this property. Note also that substituted file names are given high-order bits set so that glob will not be a nuisance... it is better of course not to edit files with funny names. ex_vadjust.c This is where the work is required to add the AL (add line) and DL (delete line) capabilities of the terminal to open and visual. Likely candidates for change are the routines "vopen", "vsync", and "vredraw"... with these capabilities you may well want to always use "vredraw"... "vsync" is the routine which leaves the dirty "@" lines on the screen. If you do any work here I would like to hear of it as I am not planning to do this but would like to have working code for it. ex_vcurs.c Note that the routine "vputchar" assumes that you can simply overwrite and have no trouble (that overstrking an "a" with a "b" works leaving a "b"). If you have terminals where this is not true (i.e. that have OS) you can send a blank to clear the position first... rumor has it that there are some ITT beasts of this flavor (at UCLA?). exr.c Sensibility detection by decoding the flags bit of a stat buffer an by looking at the magic numbers of PLAIN files should be changed to reflect the kinds of stuff you have in your file system. exw.c Note the explicit checks for /dev/tty and /dev/null by major and minor device number here. -------------------------------------------------- I would be glad to learn of any other problems you have or changes you make to ex. I will be glad to answer questions by mail or phone, and would be glad to know of any fixes and changes. Bill Joy CS Division Department of EE and CS UC Berkeley Berkeley, California 94704 (415) 524-4510 [home] (415) 642-4948 [school]