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Hello!

About documentation:

• You’ll want to get your hands on a copy of the PRMs (“Programmers’ Reference Manuals”). These are the primary reference that most people use when writing OS-level code for RISC OS. Unfortunately they are a bit out of date (the last update was about 20 years ago!), but most of what they say is still applicable today. You can view the PRMs in HTML form here on RISCOS Ltd’s site, or you can download them in PDF form here (Actually that’s an ISO of a CD image, I don’t think there are any direct downloads of the PDF versions)
• You may also want to get your hands on StrongHelp and some of the important StrongHelp manuals (e.g. the most recent versions of the OS, Wimp, InetSWIs and MiscSWIs manuals). If you use a text editor like StrongED or Zap then you can hit F1 to have it search StrongHelp for the text under the cursor – very useful for quickly looking up the usage of a function call or SWI (SWIs are basically RISC OS’s version of syscalls, and are the primary means of communication between all the different programs and OS components)
• There’s also a fair amount of documentation on the our wiki. This is a mix of old documentation (based around the content of the original PRMs) and new documentation (e.g. most new features that we add to RISC OS usually get documented on the wiki), so some care is needed when looking at the docs to be able to determine which docs are and aren’t correct anymore. One day we’re hoping to have the documentation fully online and up to date, but that’s estimated at taking at least a man-year of work, and it’s generally quite slow progress because the people who are in the best position to write the docs usually have more important things to work on.

About your task in particular:

• Omni does work with password protected shares, it just doesn’t support sending the passwords in encrypted form (which is what most modern servers will be configured for). With a bit of tweaking you should be able to enable support for unencrypted passwords on your server (see here). Alternatively you might want to consider Sunfish which is a good NFS client for RISC OS
• OmniClient, LanMan, Sunfish, and 99% of the other RISC OS filesystems will all allow access to the files they serve via the standard RISC OS file APIs. RISC OS is very good in that regard – it even has support for transparently treating zip files as directories, something which I’m not even the major operating systems even support (they usually allow you to browse it like a directory using the GUI file explorer, but do any of them actually allow you to open a command terminal there, or run/open a file without secretly extracting it to a temporary location?)
• All RISC OS filesystems (those which are fully integrated with the OS) run as modules, so if you’re interested in going down the route of writing your own filesystem you’ll want to familiarise yourself with writing modules, writing filesystems, and writing modules in C (not sure offhand of a good reference for that – unless you have a copy of the ROOL “DDE” C/C++ tools? If not, you could perhaps download the Sunfish sources and have a look at those)

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And also if there is an equivalent of the registry or /etc dir where configuration for application can be stored globally or do each application manage their own configuration independently of each other ?

There’s an area of the !Boot i.e the Choices directory, have a peek at the directory and the various applications that use it.

I don’t have DDE C/C++ at the moment, maybe i’ll get the nutpi thing, it’s included into it if i understood well ?

Correct, and it has only one restriction – the NutPi version works on the Pi and only on the Pi, but then if you have a Pi what does that matter? The compiled code works on any RISC OS machine (provided you don’t use code incompatible with your target machine).

Predictably, the forum ate my reply.

Summary:

I looked a this link http://www.riscos.com/support/developers/prm/modules.html , from what i can understand quickly, kernel module have to be coded in assembler, as function parameters are documented with registry parameters ? is the whole kernel api made in assembler ?

You can write modules in C. There are a couple of tools (cmhg in the DDE, and cmunge in GCC) which are used to help with this. They generate an object file containing the module header and a bunch of glue code to bridge the gap between the module entry points and your C code.

And also if there is an equivalent of the registry or /etc dir where configuration for application can be stored globally or do each application manage their own configuration independently of each other ?

As Steve says, !Boot.Choices is your friend. See here for a spec on how it should be used – you’d want to access it via the Choices$Write & Choices$Path system variables

As i understand there is not really an user system on riscos, it would be nice to have something to handle account information for remote host that the kernel can also access specially for password protected file system.

Correct – at its heart RISC OS is a very insecure single-user OS. There’s no builtin password/account manager, if you want a secure place to store the passwords you’ll have to write it yourself.

I don’t have DDE C/C++ at the moment, maybe i’ll get the nutpi thing, it’s included into it if i understood well ?

Yes, however (apart from what Steve’s pointed out) it’s advertised as being release 24 rather than the latest release (25). Not sure what ROOL are doing there – it seems a bit silly to keep selling the old version in a pack that’s designed to attract new users to the OS. So if you’re still interested it might be worth dropping them an email before you order to see what their plans are for updating it (unless you’re lucky and one of the ROOL guys spots this thread!)

It’s also worth considering GCC, which has the advantages of being free, having much better C++ support, and generally being easier to use when porting code from other platforms. Both the ROOL compiler & GCC are equally suitable for writing module code, the only reason I mentioned the DDE earlier is because I wasn’t sure if GCC had decent docs for cmunge (I’ve checked, it does).

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as i have seen there is a way to “intercept” system call, would this be a viable option to ‘intercept’ calls to filesystem made via the libC or swi,

File system operations are “vectored”. That means, when an operation (such as open file, read a byte, etc) happens, a routine that has requested to be notified of this activity will be called.

HOWEVER due to how the vectors work, there are a number of limitations regarding what you can safely do when in a vector routine. For example, I hook into the file vectors in order to blink an LED red (for write) or green (for read), just like a harddisc lamp. However I must schedule a callback which asks RISC OS to give me a shout when it isn’t busy and then I do the main bulk of the work. Trying to do it all directly in the vector handler makes the system blow up.

Really, what you want to do is to write a filing system. You might be able to get away with an image filing system instead of a full one – it depends on what exactly it is that you’re talking to and with and how.

For examples:

• ADFS and SDFS (common code, IIRC) and NetFS are full filing systems. Written in assembler, the code is here.
• DOSFS and X-Files are image filing systems. Written mostly in C with some bits of assembler; DOSFS is here, X-Files is elsewhere (Google ought to find it).

For Windows shares, there is a free Samba Server
- forget this one: http://riscossmbserver.sourceforge.net/
- go here: http://www.gag.de/software/smbserver/

For NFS, beware: I did have some file corruption with Moonfish/Sunfish.

If a driver is the lack of encrypted passwords in Omni (LanManFS) then, assuming the sources to LanManFS are here somewhere, how about looking into updating that?

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i saw there are samba server, but what i need is samba client as the file will not be hosted on the riscos system.

Oups :)

if there is way to manipulate module from command line or scripting in riscos.

Many tools can do this under RISC OS.

developing a platform in php

I do too. My only unsolved problem for now is lack of ssl support under RISC OS web servers.

One thing i wonder is i read that riscos is not preemptive

If you do not use Wimp, you’re in monotask mode. So your server software must be monothread. With Wimp, you have cooperative multitasking or preemptive (in a task window).

I did have the idea, some time ago, to add time limit on tasks, to get something more responsive, even if still running in cooperative mode (it’s the way Wimp2 worked under RISC OS 4).

That would be quite innovate, since if you change time limits, you can go from cooperative to RT system, on the fly. But I’m not really on kernel things.

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I you use task windows for PHP, you’ll get preemptive multitasking.

The thing that could be cool would be to get the task windows facilities, without the need to launch the Wimp.

Then, it would be possible to have a true server version of RISC OS.

First, I think we need to have a big documentation page explaining that RISC OS is not a funny Debian distro. It isn’t Linux, it is nothing like Linux……

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and i guess riscos allocation system is not really thread safe as it’s not supposed to be a preemptive os

It’s not a case of RISC OS “not supposed to be a pre-emptive os” it just plain IS NOT a pre-emptive OS.¹
As Rick said: “It isn’t Linux, it is nothing like Linux”
It pre-dates the first version of Linux by a few years.

The thing that seems to confuse people is that Linux in many incarnations developed a desktop that looked quite like the desktop that MS Windows adopted with Win2k and Win95 which basically look rather like the RISC OS desktop that appeared before them.

It isn’t windows, it isn’t Linux.

¹ Not that we wouldn’t like pre-emptive features to be added.

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Android works that way with java, and flash with AS3

Both bloated and slow.

The only point in using RO for anything would be to keep the implementation swift, add bloat like that and you’re better off running a version of ARM Linux where the facilities exist, even if a slow version.

correct me if i’m wrong, but is the task window thing a sort of framework to run windowed application in a ‘threaded’ manner ?

A means of running command line programs without leaving the desktop. Think console on Linux, or CMD on windows. Not totally accurate but near enough I suppose.

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Not without Wimp. But to be honest the Wimp use almost 0% of CPU time. So the best is simple to use it :)

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but if i understand well the principle, you can have only one loop per wimp application, and the os manage each application as a separated task in the multi tasking system,

One loop, full stop.

Each task gets offered access to the processor in turn. If one task in that loop fails to hand back control nothing else runs at all, ever.
Don’t forget
CMT = all tasks must co-operate and hand back to the launching process
PMT = at specified intervals the OS will interrupt the active task

but a wimp application cannot start a new multi tasked wimp application wihtin itself

The best for your Wimp application would be to launch CLI tasks in task windows. So they’ll use PMT.