Userland ... What is it good for

What is Userland? I hear this word mentioned here plenty, but I'm not familiar with it in this context. The only Userland reference I can think of is an old AppleScript hack called Userland Frontier ... pretty powerful scriptability stuff for macintoshes, back before anyone even heard of a PowerPC.

From the context here, I would gather it's some sort of nether region of the empeg, where users can run their own applications which may or may not do stuff to the display. But alas, this is only guesswork.

Greg

Simplistic answer:
Unlike Micro$oft's 'OS'es, unix and linux still have easily distinguishable distinctions between the kernel and applications that run on top of it. The kernel is the OS proper - it has complete access to the hardware, and completely unfettered control over things like interupts, virtual memory management, CPU schedling etc, so buggy kernel code can crash the system (ie empeg) hard. 'Userland' is basically any other non-kernel code - buggy code here is likely to crash that particular app, but the system should still deal with it gracefully.

More simplistcaly, doing something in "userland" just means that you're doing it by writing a program that can be run once the OS has loaded.

When Mark says he things a feature is best left to userland, he mean(well, i think he means) that the feature does not requre any specific support from the kernel. Hijack gives a programer the ability to write a program that can appear on the empeg menu, display stuff on the screen and trap button presses. (and more... like play sounds...). Normal programs don't need much more than this. The player software from Rio is a good example of userland software.

Hijack often blurs the line between userland and kernel mode, because many of it's features are hacks to change the way the player software functions by intercepting a system call from the player or a button press before it gets to the player. If we could modify the player software, many of hijacks features would be in the player software.

Happening in userland just means writing a specific application that can be started, stoped and restarted at will, instead of being part of the operating system that is loaded at all times. Applications are userland.

Hmm... There must be a better way to explain this... Someone else take a shot at it...

Matthew

Is there a comprehensive list of available userland apps somewhere?

I admit I didn't search just now, but I remember getiing totally lost earlier...

Armin

There's no such comprehensive list. Maybe someone (possibly me) should try to get one together on riocar.org. There are some older games, apps, etc. which don't integrate with the Hijack interface, and therefore aren't as useful. But several apps have been released that actually integrate with Hijack. I've released an alarm clock, a trivia game, and an image panner, all available on my empeg page. John Heathco wrote a text file viewer which is available on his page. Bitt Faulk wrote a preinit program which doesn't actually bind to the Hijack interface, but it's important for starting programs that do bind to Hijack. There's a couple other things out there that I'm forgetting about, and I have a couple other things under development as well.

Since I have admin access to riocar.org, I should probably try to keep an up-to-date list of apps. I'll try to do this in the next couple of days, and when it's done, I'll let y'all know.

Thanks yNot, the developers page on some of the subsites have not been updated in a while. There is no central repository for the userland apps and bits of code that have been written for the Empeg/Riocar yet.

A lot of little apps have slipped thru the cracks.

I just had a mental picture of Frankie Goes To Hollywood singing "Userland... What is it good for?" with a chorus of Mark Lords singing the "Absolutely nothing" bit.

Peter

Eeeeewwww...

Thanks, yn0t!

Userland... sounds like a bunch of whiners to me.