screen saver server

Forum: Other Help Topics
Topic: screen saver server
started by: Urban_Yeti

Posted by Urban_Yeti on Dec. 29 2004,12:01

Y-ellow All.
This DSL box will be my 4th linux boxen but please assume I'm a nubee. I'm just not sure where else I should ask these questions.

Project Description: For want of a better term, it's to be a screen-saver server. I would say it's one of my more "off the wall" brain waves but actually, in this case, it's off the ceiling. The basic idea is to turn an old P90 into a pair of very colourful down-lights. A pair of equally old VGA monitors are mounted in the ceiling behind a grill. The computer should basically, boot up into a screen saver or a series of images displayed as a slide show. You can't actually see much of an image on the monitors behind the grill but it should radiate out patterns of colours around the studio.

The Problem(s): In a nut shell, is there something equivalent to RedHat's rc.local file. Where one can add all the things that it'll do after all the booting and initialization is done. In particular, to run a series of hdparm commands etc. Also to run up the ssh daemon. And of course, boot straight into a screen saver or slide show.

At the moment the box is sitting on my bench and I have access to it through X/flux. It's also on the network and I prefer to talk to it from over here in my comfie chair. (via ssh)When it's finally working, it'll be largely inaccessible and any configuration work will have to be done over the network.

While I'm doing the screen saver thing, I'd also like to make use of the fact it's on a network and use some of the ports to control other lights. The electronics side of the thing is a no-brainer for me but I'm a bit out of my depth with anything soft. I only mention this because I'll want to have the flexability to add these things later without disturbing the basic system.

Another problem I have is with ssh. It tells me the terminal isn't set up properly. I'm just not sure what's not set up. Certainly I can't run things like MC thru ssh and 'less' spits up a warning error. It also tends to go bananas if I over step the end of any given file I might be looking at with it.

The system also seems to want to re-configure X. Not always but usually I don't have a mouse on boot up and have to run xsetup.sh to get it back. Often it's set to a video mode that the display card isn't capable of. Like 1024x768x32, The card is capable of 800x600x16 at best. And even that's actually overkill for the intended application.

It's all running off a 200meg hard drive on a system that WILL NOT boot from the CD. (the BIOS is too old for that kind of thing.) And it currently has 32meg of RAM. But I'm hoping to cut that to 16 when things are a bit more locked down. See how that works out later.

The last requirement is that it be as silent as possible. Thus the need to use hdparm to send the hd to sleepybyes as much as possible. (I'll deal with the other cooling issues as well) But I mention this in that it often seems to periodically wake up the hard drive for no obvious reason. If there's a way to calm this down it would be really handy.

Sorry for the length of this post but I'm really hoping someone might have a magic wand handy. I've been bashing my head against this thing for over a week now. Though I have to say, I'm really starting to like this distro. Bravo guys. Nice job.

Thanks in advance.

Posted by PipingFool on Dec. 29 2004,12:14

Wellllll..

Not exactly what I did. A friend of mine wanted something similar. Instead I had him install a dual VGA connection card. On one connection he has his monitor, the other one has a beamer installed on it. The beamer projects WinAMP's visualisations part into the room.

Of course, this all needs a rather powerful computer. BUT... you still could hook up the beamer instead of a monitor. I tell you it has LOTS of potential!

Posted by cbagger01 on Dec. 30 2004,05:34

The bootscript that you are looking for is at /opt/bootlocal.sh

If you have done a full hard disk install, you can edit this file and then you are finished.

However, if you are running a frugal, poorman's or livecd install you need to enable the backup/restore process in order to save your new /opt/bootlocal.sh file. The /opt/ directory is part of the RAMDISK so if you don't backup/restore the file it will disappear upon reboot.

FYI, if you want a quieter PC, you can either use a compact flash memory card with a compact flash / IDE interface to run as a fanless solid state "Hard drive", or you can also run DSL in "toram" mode where the entire OS is loaded into a RAMDISK and then the CDROM drive or hard drive is not used as part of OS functions. But you need 128MB+ RAM in order to do this.

Posted by Urban_Yeti on Dec. 31 2004,03:56

Y-ellow all.
And thanks very much. I've been following the advice and doing my own research but I'm not all that much further advanced. Suffering ADD, this stuff really ties me in knots sometimes. However, one thing that occurrs to me is that the bootlocal.sh script in /opt only happens after x is started? IE: only after a user has logged in.

I got SSH to run automatically by editing stuff in rc5.d , rcboot and init.d etc. However the network won't actually come up until I log into X. And even then, it seems to go off waiting for a dhcp response which it won't get because I don't use it on my network. Adding to that, the mouse still won't come up without a re-config of x first. Although I may have indeed fixed that with the mouse script in /opt. I just haven't tried it right now.

I don't know what the difference is between a frugal install and a full HD install. I thought a HD install was a HD install. End of story. I can't boot from a CD so it's not like I can do a live CD thing.

Out of interest and in case you were wondering how I actually got the thing installed. I actually plugged the 200 meg drive into another machine (PII) which COULD boot from the CD. I then did a first stage install to the hard drive on that box. I used all the intended hardware from the target box during this phase but it seems I needn't have bothered as it checks all that on boot anyway. I replaced the network card in the mean time anyway since the 3com card seems to have died.

And also just out of interest. I like the idea of using a projector. But if I could afford a projector, even an old epiphore type, I'd be using it to watch stuff on. Not that I could fit any kind of projector in here and find something flat to project it onto. But I'd often wanted to use a projector like this for live performances. But where the projector is actually projecting back into the audience like they use to do with lasers. The idea is that if there was some degree of focus to the back of the venue, then a computer generated "DOT" on the screen would actually behave somewhat like a laser. Only more colourful and more flexible. But I digress...

The purpose of this project is actually to use up some old technology that would otherwise find it's way into land-fill and be employed as a water-way polluter. The two VGA monitors are old. One of them was given to me with a view to ripping off the VGA cable to make a KVM cable with. The other, a friend found on the street (Literally) during hard rubish collection week. Thinking it was a whole computer (I know some computer illiterate people. Sad by true.) he dumped it at my place along with an old keyboard. I try to let nothing go to waste here and now that there were two identical monitors laying on their backs under my carport, it spawned the idea.

200wats of downlight with filtered gells for colour. Or a pair of computer monitors with coloured phosphor chewing up 200watts with the gain flat out. Do you think I'd take the easy option? The monitors aren't just bolted to the ceiling or anything. My builder mate and I, stripped them down and mounted them _IN_ the ceiling. Behind a long grill which is gold plated no less. (Always carry a suitable sized net, you never know what you might catch.) Now that the studio looks like Saddam's bathroom, I have to get some kind of picture on them. And I haven't even looked at a suitable screen saver to run yet.

I had indeed thought of running a pair of video cards. I tried it but it was looking hard enough just getting x up on the one at the time. Instead I'm stepping back to plan B. which is to simply build a Y adaptor. No buffering since I'll probably be running the monitors near to flat chat anyway. And it doesn't matter that the picture is the same on both.

In the mean time, here's my latest clue. To get X up of it's own accord, would I actually have to boot into single user mode? I have to admit that I'm not really clued up on exactly how X works. Espeically in DSL. Where the log-in is actually on the command line and doesn't seem to call X unless you're actually logged in. Sorry if I seem confused but what can I say. I'm confused. And that's on a good day.

Anyway, thanks very much once again folks. I'm most grateful for your thoughts and advice.
Be absolutely Icebox.

Posted by cbagger01 on Dec. 31 2004,08:08

A full hd-install will create a Linux partition on your hard drive and then uncompress the entire file system from the CD and copy it over to the hard drive. It will probably use up about 125-140MB of hard drive space to do an hd install and you will need some extra space for a swap partition (64MB should do it).

So a full hd install will work on your system but it won't leave much room leftover for expansion or for userfile storage.

A frugal install works differently. With a frugal install, the read-only compressed filesystem is copied over directly from the livecd. So basically it is like running a virtual livecd but from your faster hard drive. The other advantage is that the compressed frugal installation only takes about 50MB of disk space, leaving plenty of room for personal file storage and swap partition. Loading up files from the operating system is slightly slower than a regular hard drive install because the CPU needs to decompress them on-the-fly while the files are loading up but my guess is that the speed penalty is minimal compared to the extra free disk space that is created.

Hope this helps.

Posted by Urban_Yeti on Jan. 03 2005,03:27

Y-ellow all and thanks cbagger for the confirmation.
I'm actually learning quite a lot from this process but I'm not really any further advanced. This stuff can be mind numming for an ADD sufferer at the best of times but DSL is definitely resiting any attempts to change it.

I realize this is probably a function of it being initially a live-CD idea but if anyone can tell me how to turn that off I'd be most grateful.

I chanced inittab so that it would boot into runlevel 3 but it still boots into 5. It seems to be ignoring absolutely everything. I've poked around at every script and file I could find that looked even remotely connected and I just go round in circles.

It doesn't appear to be a frugal install. It takes up about 112 meg on the drive. IT's actually a 220meg drive so there's 45meg of swap partition. I DID type "hdinstall" etc initially so that should be an actual hdinstall shouldn't it? Or am I just using the wrong distro for this job? After looking round DSL seems about the smallest and most complete distro that offered graphics. I'm told I can do this with raw frame buffers but it looks like even more a pain to set up that way.

Anyway, Thanks once again. Any suggestions would be grately appreciated.
Thanks in advance.
Be absolutely Icebox.

Posted by cbagger01 on Jan. 03 2005,18:01

Any changes that are made to files that are part of a true hd install should remain permanent.

The runlevel command may not work properly if the "startx" command is included in your bootlocal.sh file or other startup scripts.

However, changes made to a frugal or livecd system will be undone after every reboot unless the file is backed up using the DSL backup/restore process and the filetool.lst configuration file.

Read up on the DSL start guide for more information.