Subject: [linux-audio-dev] Re: Realtime wars ... Montavista vs Lineo
From: David Olofson (david_AT_gardena.net)
Date: Wed Sep 13 2000 - 08:17:27 EEST
On Tue, 12 Sep 2000, Benno Senoner wrote:
> Hi,
>
> Lineo's claims in these PR make me sick:
>
> http://alllinuxdevices.com/news_story.php3?ltsn=2000-09-12-001-02-NW-LF-RT
> http://alllinuxdevices.com/news_story.php3?ltsn=2000-09-11-003-03-PS
Well, I'm off-line right now, but I think I have some kind of idea
how Lineo is doing things... (Seen some "mistakes" before.)
> While Montavista's preemptive kernel prototypes are not perfect yet, I think
> they are a step in the right direction and will help the linux realtime
> community, especially those working in userspace like we audio folks.
Basically, RTL and RTAI are meant for very low latency systems, and
applications where deadlines have to be very hard RT despite low
latencies - which is not possible to achieve with reasonable CPU
requirements with memory management and other "user space stuff".
That is, BeOS, Montavista and Linux/lowlatency are doing one thing -
QNX, RTL and RTAI are doing something different. There is a big
overlap, but there's orders of magnitude of difference in CPU
power/latency ratio and other things.
> But what I hate is that Lineo claims that "their" realtime linux solutions,
> (which is basically RTLinux (invented by Victor Yodaiken)) are better than
> Montavista's ones.
They are probably better for control and embeded RT applications, but
by now it's very obvious to me at least, that RTL/RTAI is not suitable
for "workstation multimedia" style things, such as DAWs and generic
audio/video workstations. RTL/RTAI is great for ultra low latency
and/or very timing critical stuff, where you can accept that you have
to hack/port all drivers yourself, but it's very unsuitable for
"normal" workstation applications.
Or; RTL/RTAI is meant for writing drivers and system software, while
the User Space Club of RTOSes are meant for *applications*.
> What kind of stuff have they contributed to the linux community ?
Well, they are selling a nice RTL/RTAI distro, and they have released
useful tools under the GPL... But still, they're too closed for my
taste. I'm not currently using their products, and considering their
policy, I probably won't, possibly except for the GPLed stuff.
> If Redhat and Suse mentality was as closed as Caldera's one
> (and related subsidiaries like Lineo), then Linux would still be an
> unknown/dead OS.
I don't know if it's that bad, but I have seen very M$ish texts from
Lineo before (later blamed on someone who didn't have a correct
full picture of the situation, or something...) - maybe the documents
above are even worse!
> At least Montavista shows us the source of what they do, while Lineo seems only
> good at making negative PR against competitors and market open source RT
> solutions (RTLinux and RTAI) as their own.
I have observed lack of credits for RTL/RTAI code, and some other M$
style moves, yes...
> Do they really believe that we will code software like EVO using
> "their" superiour RTOS solutions ?
Did they claim something like that!? Then, either whoever wrote that
has no clue, or user space hard RT (exists already, although limited)
*with* ports of the major drivers to hard RT will arrive sooner or
later.
I guess I should read those docs some time when I feel like getting
pissed off - or have a laugh... ;-)
//David
.- M u C o S --------------------------------. .- David Olofson ------.
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