Develop on-device [Was: Re: [fpc-devel] "embedded" again]

[Mark Morgan Lloyd]

Michael Schnell wrote:
> On 01/15/2013 12:29 PM, Mark Morgan Lloyd wrote:
>>  I was routinely able to run the server-end of VNC (i.e. the code that 
>> runs on the same machine as the app) on a Slug, 
> I even do have a Slug for testing (the one that recently was replaced by 
> the more powerful QNAP)
> 
> How did you install the VNC server ? (hopefully not "apt-get", as this 
> is not available on the QNAP).

In the case of the Debian-based Slug... I'm sorry but it was apt-get. 
I'd presume that one of the standard sources could be compiled although 
you'd probably need X-devel stuff, this is getting outside my area of 
competence but I can say that different variants of VNC have slightly 
different command-line formats (more detail if you need it).

>> on X-based systems it simulates an X server so doesn't need a frame 
>> buffer etc. 
> I did not know that. ( Supposedly I was mislead by what I found out 
> about VNC on Windows.) This suggests that on Linux, VNC might not be 
> slower or more memory hungry than NX.... Great !

Windows is very different, in that case VNC works by "scraping" the main 
screen and then trying to work out what's changed. On unix (for a 
non-root session, i.e. the server starts in response to LAN activity) it 
sets up its own X server, that gives it the capability of logging 
changed areas and under some circumstances it can be significantly more 
efficient than running X over the LAN.

> Yep. Its obvious how they work, but they might be memory hungry and slow 
> when it comes to X, as the full X server needs to be installed and run 
> on the target.

Not /the/ full X server, /an/ X server. And in the case of a dummy that 
can be pretty simple, since all it's got to do is tell apps that it's 
got minimal competence and let them sort out how best to proceed. I must 
admit though that apps (strictly, widget sets) are much less tolerant 
than they used to be: some have decided problems if they can't get e.g. 
sufficient colour depth.

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

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