Hello everybody out there using minix -

I'm doing a (free) operating system (just a hobby, won't be big and
professional like gnu) for 386(486) AT clones.  This has been brewing
since april, and is starting to get ready.  I'd like any feedback on
things people like/dislike in minix, as my OS resembles it somewhat
(same physical layout of the file-system (due to practical reasons)
among other things).

I've currently ported bash(1.08) and gcc(1.40), and things seem to work.
This implies that I'll get something practical within a few months, and
I'd like to know what features most people would want.  Any suggestions
are welcome, but I won't promise I'll implement them :-)

                Linus (torva...@kruuna.helsinki.fi)

As for the features; well, pseudo ttys, BSD sockets, user-mode
filesystems (so I can say cat /dev/tcp/kruuna.helsinki.fi/finger),
window size in the tty structure, system calls capable of supporting
POSIX.1.  Oh, and bsd-style long file names.

It also uses every feature of gcc I could find, specifically the __asm__
directive, so that I wouldn't need so much assembly language objects.
Some of my "C"-files (specifically mm.c) are almost as much assembler as
C. It would be "interesting" even to port it to another compiler (though
why anybody would want to use anything other than gcc is a mystery).

Unlike minix, I also happen to LIKE interrupts, so interrupts are
handled without trying to hide the reason behind them (I especially like
my hard-disk-driver.  Anybody else make interrupts drive a state-
machine?).  All in all it's a porters nightmare.

                Linus (torva...@kruuna.helsinki.fi)

I don't like the chmem mechanism of Minix. Processes should start with
a minimal size and grow as they need to until they run out of RAM or
disk space. Paging to disk would be nice, too.

If your OS is message based I would like to have arbitrarily large
messages. They could be implemented efficiently by mapping the pages
into the receivers address space (or just passing a pointer on 68k
systems without MMU). Oh, yes, and the addressing scheme for messages
should be different than in Minix. Messages should not be sent to
process slot numbers, but to ports. That way, user processes can use
messages, too, and it is easier to add your own servers.

/*
 * This layer works based on small simple 'scripts' that are installed
 * at the start of the command and drive the chip to completion.
 * The idea comes from the specs of the NCR 53C700 'script' processor.
 *
 * There are various reasons for this, mainly
 * - Performance: identify the common (successful) path, and follow it;
 *   at interrupt time no code is needed to find the current status
 * - Code size: it should be easy to compact common operations
 * - Adaptability: the code skeleton should adapt to different chips without
 *   terrible complications.
 * - Error handling: and it is easy to modify the actions performed
 *   by the scripts to cope with strange but well identified sequences
 *
 */

An interesting way to write a device driver.  I believe this is a very old
technique, too.

From Fiji