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diff --git a/appl/examples/minitel/README b/appl/examples/minitel/README new file mode 100644 index 00000000..82f3202e --- /dev/null +++ b/appl/examples/minitel/README @@ -0,0 +1,209 @@ +Minitel Emulation for Inferno + +This directory contains the source of `miniterm', a minitel emulator +for Inferno. Miniterm is written in Limbo. The main components are: + + miniterm.m - common constants + miniterm.b - terminal emulator, messaging and Minitel `protocol` + event.[mb] - inter-module message format + keyb.b - Minitel keyboard module + modem.b - Minitel modem module + screen.b - Minitel screen module + socket.b - Minitel socket module + arg.m - basic command line argument handling + mdisplay.[mb] - Videotex display module + swkeyb.[mb] - Minitel aware software keyboard + + fonts.tgz which expands into: + + fonts/minitel - external and subfont directory (`bind -b' into /fonts) + fonts/minitel/f40x25 - 40 column external font + fonts/minitel/14x17 + fonts/minitel/14x17xoe + fonts/minitel/14x17arrow + fonts/minitel/f40x25g1 - 40 column semigraphic external font + fonts/minitel/vid14x17 + fonts/minitel/f40x25h - 40 column double height external font + fonts/minitel/14x34 + fonts/minitel/14x34xoe + fonts/minitel/14x34arrow + fonts/minitel/f40x25w - 40 column double width external font + fonts/minitel/28x17 + fonts/minitel/28x17xoe + fonts/minitel/28x17arrow + fonts/minitel/f40x25s - 40 column double size external font + fonts/minitel/28x34xoe + fonts/minitel/28x34arrow + fonts/minitel/f80x25 - 80 column external font + fonts/minitel/8x12 + fonts/minitel/8x12xoe + fonts/minitel/8x12arrow + +The fonts subdirectory should be bound into /fonts: + bind -b fonts /fonts +or the directory fonts/minitel copied to /fonts/minitel before invoking the emulator. +The names of the external fonts are +known to the Videotex display module. Similarly, the files: + /dev/modem + /dev/modemctl +are known to the modem module, but you can ignore them if +(as is almost certain) you are using the Internet-minitel gateway +and you haven't got appropriate modem hardware anyway. + +To build + mkdir /usr/inferno/dis/wm/minitel + mk install + +The code models the structure outlined in the Minitel 1B specification +provided by France Telecom. However, much more interpretation was +required to display the majority of screens currently seen on Minitel. +Additional information (although sketchy) was found on the Internet by +searching for Minitel or Videotex and also by examination of the codes +sent by minitel servers and experimenting with replies. There must be +some more up to date information somewhere! + +We don't support downloadable fonts, but correctly filter them out. + +The file miniterm.b contains the code for the minitel `terminal' with +which the other modules communicate. The keyboard, modem, socket, +screen and terminal are run as separate threads which communicate by +calling: + send(e: ref Event) +The clue to the intermodule communication is in Terminal.run which +does something like: + for(;;) { + ev =<- t.in => + eva := protocol(ev); + while(len eva > 0) { + post(eva[0]); + eva = eva[1:]; + } + # then deliver any `posted' messages (without blocking) + } +An Event `ev' may typically be an Edata type (say from the modem) or +an Eproto type for internal interpretation. In the call: + eva := protocol(ev) +The function protocol() dissects Edata messages to produce an inline +sequence of Edata and Eproto messages. The function post() queues +messages for delivery to the appropriate modules. For example, data +from the modem might be destined for the screen and the socket module. +Messages are queued until they can be delivered. That way the line: + ev =<- t.in +is executed in a timely way and the other modules can be written to +make blocking writes (via send()) and to service reads when they are +ready. + +In many places in the code lines appear with comments like: + if(p.skip < 1 || p.skip > 127) # 5.0 +These refer to sections of the Minitel specification which explain the +code. + +The mdisplay code provides a Videotex display using Inferno +primitives. The screen, keyboard and modem modules interpret data as +described in the equivalent section of the Minitel specification. The +socket module has not been implemented but currently performs a `null' +function and could easily be added if required. + + +- Namespace +We always expect the fonts to appear in /fonts and the softmodem +to appear as /dev/modem and /dev/modemctl. + +- Invocation +If invoked with no argument, miniterm uses the France Telecom +internet gateway by default (tcp!193.252.252.250!513). +If the argument starts with `modem' then +a direct connection through /dev/modem will be established. + +An argument beginning with anything other than `modem' will +be assumed to be an address suitable for dial(). For example: + + wm/minitel/miniterm tcp!193.252.252.250!513 + +will connect to the current France Telecom internet server. + +For direct connections a modem `init' string and an optional +phone number can follow the modem prefix, as in: + + wm/minitel/miniterm modem!F3!3615 + +or + + wm/minitel/miniterm modem!F3!01133836431414 + +The `F3' is the code which instructs the softmodem to enable V.23 +and needs to be passed when connecting to the FT servers. +To use pulse dialing instead of tone dialing the phone number +can be prefixed with a 'P' as in: + + wm/minitel/miniterm modem!F3!P3614 + +If the parameter specifies a network connection or a direct connection +with a phone number the software will attempt to connect immediately. +If Cx/Fin is used to disconnect and then re-connect it will use the +same IP address for a network connection or prompt for a new +phone number in the case of a direct connection. When prompting +for a new number the top row of the screen is used to allow the user +to edit the last used number. Simple editing is available, and the minitel +keys do the obvious things. + + + +** Notes on the 15th December 1998 Release ** + +- Software keyboard +A version of the software keyboard which understands some of +the minitel keyboard mappings is included. For example, hitting 'A' results +in a capital 'A' on the screen in spite of the Videotex case mapping. + +- Minitel function keys +The minitel keys are displayed on the right hand side of the screen +in 40 column mode on a network connection +and can be swapped to the left hand side by hitting the <- key. +In direct dial mode and 80 column network mode the keys are +displayed at the bottom of the screen. +In network mode they are re-displayed as appropriate on 40 to 80 +column mode changes. + + +Known Omission +------------- +- Error Correction (direct dial only) +There is no screen button to enable error correction in the release. +If a server asks for error correction it will be enabled. It looks as though +we need to include a key to enable it. Without it direct dial screens are +occasionally corrupted. + +- Software Keyboard Handling +We need to add some code to update the software keyboard and +bring it to the foreground on a mode change. + +- Full 80 column support +I am aware of some screens which don't look correct in 80 column +mode (and others that do). See `EMAIL' then choose USENET and +press SUITE a few times. I believe it behaves as specified but as we +have seen with the 40 column Videotex mode the specification +is not sufficient to display most of the minitel screens correctly. +80 column support needs just a little more work. +It may be, too, that the 80 column font could be made much more +readable by utilising a few more pixels on the screen now that we +are able to cover the toolbar. + +- Full toolbar integration +Experimentation will show whether there needs to be more +integration with the toolbar. + +Known Bugs +---------- +- Softmodem disconnection +Often, the modem does not hangup correctly. + +- Choose `USA' from a network connection +USA (from a network connection) gives an `iC' in bottom left hand +corner of screen. Possibly a server issue. Doesn't occur when +connecting directly. The server is really sending this sequence. +Both the FT emulator and their explorer plug-in suffer from it too. + + +John Bates +Vita Nuova Limited |