Sunday, April 06, 2008

lab 87 - mux for nintendo ds

NAME

lab 87 - mux for nintendo ds

NOTES

In an earlier post I talked about updating mux to 4th edition Inferno in the hope of one day running it on a Nintendo DS.

Well, Inferno is now booting on the DS so I got to try it for real.

I started with getting the mux window manager working in standard inferno. Then I changed the resolution down to 256x192 and tried to get everything to fit. The files in this lab include the version of mux I ended up putting in the nds file running on the DS.

Things to try if you download it. Rocker moves up and down selection. 'A' key enters, 'B' key backs out back up to the higher level. 'Start' key returns to the top level menu.

Try Today's Newspaper, and The Thisburgh has the only working graphic. Under news, click through to actually read an article. Under games, try connect4. Audio control would look cool if any of the graphics actually came in. The Financial Reports gives a ticker. It scrolls slowly only because of the sleep interval in the code is incorrect.

If you want to try this version of mux using hosted inferno just remember you need to compile prefab into your emu. Include prefab in the mod and lib sections of your emu config file, also uncomment prefab in the /libinterp/mkfile.

Mux uses irsim for key controls. I changed my local inferno-ds code to have the DS keys output the same characters as used by irsim.

The files in this lab include the movies and tvlist apps and their data. The data didn't fit on the 4MB .nds file. But they will fit when we get the GBA ROM or dldi interface working.

I think mux is a good path to follow for DS development. It's small, starts quickly, uses the keys effectively since it was designed for remote controls, the programs are easy to understand, and they hit most of the applications I'd like to start with, small games, news reader, email reader, simple database browser (movies, tvlist), and audio.

FILES

code for lab 87

lab 86 - srv

NAME

lab 86 - srv

NOTES

This from a post on 9fans, and also on Tip O' the Day

% dc >[0=1] | echo 0 > /srv/desk

Plan 9's srv(3) acts as a bulletin board for open file descriptors, other namespaces see all the files in srv, and so can read and write to /srv/desk.

Inferno has srv(3) which is a file2chan registry, but is also visible to all namespaces on the host. (see also srv9(3))

The current implementation of sh-file2chan(1) does not allow the above. The closest I got was,

% load file2chan
% calc >[0=1] | {file2chan /chan/desk {rblock; putrdata &} {fetchwdata > /fd/0}} &

% stream -b 1 /chan/desk
% echo 1+1 > /chan/desk

I tried implementing a command equivalent to srv(4) on Plan 9. It takes a command block or network address and post it in the srv registry.

% srv {calc >[1=0]}  /chan/desk

It using an existing '#s' instance if there is one, else binds a new one. Now we can open a console to /chan/desk from another window

% {cat & cat  >[1=0] < /dev/cons} <> /chan/desk

and other windows can write to /chan/desk, the output will be seen in the console.

Questions.

  1. Why isn't Plan 9 srv(3) in Inferno?
  2. File2chan(2) seems under used. Is that because of the shell interface sh-file2chan?
  3. Is there another interface that would make file2chan more usable?
  4. Mount(1) supports mounting from a file, as Plan 9's does. But the inferno srv(3) device must do extra copies of the read and write buffers to implement the interface. Is the file interface of Plan9 srv more elegant than the extra file2chan syscall in Inferno?
  5. Aren't there benefits to using channels in Inferno that make file2chan preferable?

Files in this lab are for the inferno srv(4) implementation.

FILES

lab 86 code