Multiseat setup via Userful
As I had blogged a while back, multiseat use broke following the normal upgrade to Ubuntu 8.10. I had also suggested a fix but it turns out that the fix didn't work. So we had a clear regression -- multiseat use of a single Ubuntu workstation with two screens, two keyboards and two mice no longer worked. Consequently, the kids ended up 'serializing' access to their computer letting the second screen go idle.

Shortly after Christmas, that computer suffered a catastrophic disk failure (and as an aside, I hate LVM when that happens...). So I reinstalled, this time using the Ubuntu rather Kubuntu variant. This should allow use of Userful Multiplier --- a commercial multiseat solution with free two-seat licenses. The base package even comes via the Ubuntu repos.

I still had a couple of minor issues. One was possibly related to the Radeon card (as in: don't drive one monitor in dvi mode and one in analog mode but rather use both in analog mode via a dvi/analog dongle) so the live cdrom offered by Userful just went into a perpetual 'reconfigure, reboot, reconfigure, reboot, ...' loop. Another hitch was that their license manager no longer wanted to use the license key I had requested in November when I tried in vain to use Userful with KDE. And of course I wouldn't a new key as the home ip address hadn't changed... Now, with a newly requested key from another IP address, things appear to work at last using the default Gnome setup --- and the kids are back in proper 'parallel' use of their workstation.

All in all, Userful Multiplier is a nice and useful product especially as long as stock XFree does them the favour of no longer competing in the basic two-seat case.

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Multiseat update under Ubuntu 08.10
The aforementioned multi-seat setup allowing two kids with two screens/keyboards/mice connected to one computer required a minor update under the new Ubuntu release. The Xephyr 'x11-server inside an x11-server' that is used to display two distinct sessions on two distinct monitors didn't seem to recognise the mice and keyboards anymore.

Somehow not explicitly specifying them helped. I.e. the calls to the script /usr/sbin/Xephyr-path.sh from /etc/gdm/gdm.conf now read

[server-Xephyr1]
name=Xephyr1
command=/usr/sbin/Xephyr-path.sh -display :0 -br -dpi 100 -xauthority /var/lib/gdm/:0.Xauth -screen 1280x1024
handled=true
flexible=false

[server-Xephyr2]
name=Xephyr2
command=/usr/sbin/Xephyr-path.sh -display :0 -br -dpi 100 -xauthority /var/lib/gdm/:0.Xauth -screen 1280x1024+1280+0
handled=true
flexible=false

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Easy multi-seat (two screens, keyboards, and mice off one computer) setup
This is 'back to school' season aroun here. So on Saturday we went and set up two desks for our two kids. And with that I finally converted 'their' computer to a working multi-seat setup. At first, I had fiddled with two distinct (ATI Radeon) graphics cards. Somehow I never got x11 to recognise both cards properly.

But two cards are not needed. As the machine is running a standard Kubuntu setup, I just followed this excellent three-part tutorial for Ubuntu multi-seat setup which describes the process using nothing but standard Ubuntu software. From setting up a 'big desktop' spanning two screens (which is easy enough using one card via the vga and dvi outputs), it is fairly straightforward to modify the gdm.conf setup to spawn two gdm greeter instances using the Xephyr nesting xserver.

So far, all is well. We'll see what possible shortcomings we will find. The GL extensions are not supported, so some eye-candy will be unavailable.

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Into the sunset
I finally got around to dropping four old computers off to recycling. Triton, a community college nearby, had a recycling event where students volunteered, and so I finally got around to dropping two generations of old computers off.

Old computers, I hear you ask, well how old? Real old. The older two were from an age where the bios didn't yet boot off cdroms -- circa 1995. We had bought those in Kingston just off the Queen's campus. These were respectively a pentium 90 and a pentium 100, which still have traces on the web as miles.econ.queensu.ca (e.g. in a number of Debian changelogs) and rosebud.sps.queensu.ca which was of course Lisa's office machine and for a while the only internet address showing SPS.

The next two were purchased around 1999 in Toronto on College St just north of U of T's main St George campus. Those, an AMD k6-2 300 and a Celeron overclocked to 450 MHz (woot :) lived happily in the basement of our Toronto home, forming the first lan I built. If I recall they were initially connected using a crossed ethernet cable and a second nic to the ISP. Oh boy.

At least those latter two still boot off Knoppix. And do they ever feel slow. To think now just how many Debian packages I must have built on at least three of these over the years... And each machine must have gotten at least five decent years of usage out of them. One of the second generation computers eventually morphed into the kids play computer but even retired from that a while ago.

In any event, it was good to have them recycled, and also good to have been able to do so without paying a fee as is increasingly common. So cheers to Triton. I may be back in a few years as there are still a few computers spread across the house.

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NAS'ed
I had been eyeing an inexpensive network-storage device -- for the non-geeks: think of a hard disk with an ethernet port and some controlling software -- for some time. I was aware of some of the hacking efforts around a few of these but somehow nothing really appealed. I was sort-of looking for nslu2-with-a-disk, and preferably not too expensive.

Lo and behold, that's what I saw today in my techbargains feed: a Buffalo LinkStation Live which contains a 500gb SATA for $199 after rebates. Some quick googling lead to these wiki pages which looked promising: anything from enhancing the stock Linux setup by enabling a few more services to a custom Linux distro (similar to my wrt54 router running linux) to reportedly some work-in-progress for a native Debian installation. Nice!

So off I went, ordered the thingie for local pickup for an additional 5% off and picked it up a little later at the local Circuit City (where visits are seemingly a recurring event these days). The documentation is very brief and insist that you install something on Windows -- just to find that the little box autoconfigures itself just fine. Presumably some network discovery is going to find the assigned dhcp address which is needed for the web interface. A few minutes later, a new (fixed) IP address was assigned, ntp was enabled and that was about that.

After dinner, I quickly followed this tutorial to get the box a bit more Unixy without going too far (yet) from the default: start up telnet via a simple Java command-line tool, login, then enable ssh, set it up in /etc/init.d, add some extra binaries. All very quick and simple [ with the caveat that the addons.tar didn't want to get there via the Java tool, so manual scp once 'inside' did the trick ].

NFS, which I like for shuffling files around, appears to be little trickier for this ARM-based LinkStation Live. So at least for now I am content with simple rsync'ing of my backup directories on the few machines here. Much better than the current setup with mutual backups between workstations and semi-permanently being out of space.

All in all a rather pleasant gadget and recommended at the price. The extra $100 in rebates are valid from today to the 12th.

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Dear Samsung,
Your ML-3051N is a lovely little 'network printer. Hopefully, it will serve us well in the next few years as a replacement for the thirteen year old HP Laserjet ML we bought (for about five times the price: a native postscript printer was rather expensive in 1994) a long time ago. And you even mention that it can talk to Linux! But still, I have a few things to talk to you about:

1. as you mention Linux, it's a tad odd that you enumerate various flavours (RH 8 to 9; FC 1 to 3; Mandrake 9 to 10.2; SuSE 8.2 to 9.2) but happen to exclude the two variants that run around here: Debian and its cousin Ubuntu. Besides, the versions of those other flavours are a tad old, no?
2. as you ship Linux software on a cdrom, it is even odder that the install shell script fails (note: spaces between #! and /bin/sh may not be a good idea). Fails not once, but twice: you say /bin/sh, but you meant /bin/bash as you use features of the latter. Oh well, I guess we all made that mistake in our youth. Irregardless, the software never installed. Which is a pity as this would be about the first 'household appliance' I bought with native Linux support. So close, and yet so far.
3. the control panel is a cumbersome way to set a static IP and to turn the odd protocol off.
4. did I really have to install all this windoze stuff on my wife's laptop just to learn that the printer does in fact have a nice web interface? You could have mentioned that with Linux info, no? It is in fact a rather nice and complete web interface.
5. as you supply networking support, do you really have to enable every possible protocol under the sun? I mean slp, snmp, multicast dns, dynamic dns, raw tcp, ipp, ethertalk, netware ...? I still see my cable modem go down 'seemingly randomly' rigth after I print even though I now disabled just about everything but raw tcp to port 9100 as well as ipp to 613. Still, dropping the cable connection just because the printer wakes up is odd, isn't it?
6. Cups, foomatic and all the other printing goodies do not yet know the ML-3050 family, so we are making do with the ML-2151NPS settings for postscript. Works fine, so I won't bother copying the ppd file from the cdrom to the handful of computers around here.

Updated to fix a markup error. And the shebang space is standard, I am told.

Postscriptum: Turns out it was 'just' the power surge. Putting the cable modem and the router onto a different wall outlet, and a surge-protector and battery backup ups to boot, fixed the issue.

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Too good to be true?
Robert Cringely opens his new-look digs (now in blog format which is funny given how his columns predate the term by a good while, even though they always were `web logs') with a stunning column about a new disk technology coming to market next year:

[...] disk drives that held up to three times as much data in the same space, were more reliable, actually cheaper to build, and used 70-95 percent less energy to run.
[...]
Our metal foil drive costs less, not more, and spins up so quickly that data can be read from disk as fast or faster than it can be read from flash. Who needs a hybrid disk drive?
[...]
The market potential is one billion computer disk drives and one billion mobile phone drives per year. And it all starts around this time next year when metal foil drives will begin to appear under well-known brand names.

Bring'em on.

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Some notes on wrt54g configuration
If I post'em here, I may end up not losing them in case I need to revisit this one.

OpenWRT Configuration

1. Initial flashing worked much better with the automated loop from the GettingStartedTips

     
           while true; do
              cat <<END | atftp --tftp-timeout 1;
           verbose
           trace
           connect 192.168.1.1
           put openwrt-g-code.bin
           END
              sleep 1;
           done
   

   This assumes that you have a Linux box plugged into the box with a tftp client pushing the binary image to the wrt54g which will read it thanks to the ping trick described User Guide
2. If something goes wrong see Troubleshooting: power cycle, and hit reset for 2 seconds just after the DMZ light goes on. This sets the box back to defaults with address 192.168.1.1.
   Telnet in, and run mtd erase nvram; reboot
3. For first use, edit dnsmasq.conf as per Using and here.
   Set the gateway and router (options '3' and '6' at end) to address of the lan interface the wrt54g clients should see.
4. For testing off the princinpal 192.168.1. network, set the ip addressit to 192.168.2.1 per nvram set lan_ipaddr=192.168.2.1; nvram committ' and editing of /etc/dnsmasq.conf followed by reboot
   That worked -- laptop now gets 192.168.2.179, and pings outside sites like Google just fine.
5. ipkg update works as well, ipkg install dropbear gets ssh so that telnet can be disabled.
6. . Configure firewall to allow ssh from outside / forward ssh from outside a la Section 6 and 7 of GettingStartedTips. Same for http.
   Add additioanal -s a.b.c.d option to allow ssh only from given address a.b.c.d
7. Configure wireless per Q24 in the OpenWrtFAQ

   	nvram set wl0_wep=on
   	nvram set wl0_wep_bit=128
   	nvram set wl0_key1=DEADBEEF12345DEADBEEF12345
   

   Also set the wl0_ssid, and define a specific list of MAC addresses we talk too:

   	nvram set wl0_maclist='XX:XX:XX:XX:XX YY:YY:YY:YY:YY:YY'
   	nvram set wl0_macmode=allow 
   

8. Put it all together for the drop-in replacement on 192.168.1.:
   • nvram set lan_ipaddr=192.168.1.x
   • switch /etc/dnsmasq.conf accordingly
   • adjust firewall /etc/init.d/S45firewall
That's it.

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New gateway
Returning from work yesterday, I found that the hard disk of the old, old gateway box was giving in. The computer is old, really old -- purchased in 1998 on College Street in Toronto -- and it had acted admirably as my gateway / firewall / nat box for all that time. First as the principal workstation, as well as webserver, name server etc pp and later with fewer and fewer services. But I kept a large /home on it for too long, and turned a backup / partition into additional swap space when more virtual memory was called for. For this lack of a backup partition I was now paying as the fsck could not repair /dev/hda1 and I never rebooted the box for lack of a second / partition.

But then it didn't matter. In December, I had finally bought what Cringely so aptly called a disruptive technology: one of those inexpensive Linksys WRT54G. Somewhat procrastingly, I had started to both configure the box using the admirable OpenWRT Linux operation system one can load onto it, and migrate essentially all services of the old gateway. So today and yesterday I finished the setup, which worked well enough. Now it is the new gateway, redirecting http to the bigger server in the basement, same for ssh from less than a handful addresses, rejecting the rest and is otherwise NATing away. Luckily, in the interim I had the older Speedstream 801.11b gateway I had once bough along with a Speedstream 801.11b card that turned out to be a piece of crap. Still, it was easy to cover the basics with it for a day to not be off the net, but it doesn't of course offer the magic of iptables needed for the finer-grained firewalling and access control, which I intend to add soon and the host of other Linux goodies that are available for OpenWRT thanks to Linux networking.

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