Re: [SLUG] Affordable wireless AP hardware to support 30+ connections
On Tue, Nov 01, 2011, Jeremy Visser wrote: And I think what Adrian is saying is not that 30+ devices on open source is impossible, but the commercial APs have some hacks to improve performance. I'm not sure precisely what Adrian is referring to though, to be honest. You can ask :) I'm trying to encourage wireless development, not giveout answers which I don't have the time to try and fix. So if you're looking to deploy this kind of thing and you have issues with it, find a developer (or hack on the code yourself) and ask questions. That way things will improve. :) Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Affordable wireless AP hardware to support 30+ connections
The problem, unfortunately is:
* Supporting 30+ connections on a single AP is doable;
* .. and the commercial APs do it;
* .. but that source isn't open source.
So in short, you can likely support 30+ clients associating to an Atheros based
device (but there's limitations on hardware encryption keycache slots and I
haven't ever tested Linux/FreeBSD to see how they cope if you associate more
than the available keycache slots) but without the { hacks, clever things } done
by commercial firmware, it's going to be hit and miss.
If you'd like to _write_ those hacks, I'll tell you what they are and help you
write them for contribution back to Linux/FreeBSD. (As figured out by yours
truely,
not by any kind of reverse engineering or via NDAs.)
Adrian
(Yes, I hack on 802.11 stack stuff and Atheros driver source these days.)
--
SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/
Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Article, Linux, APC.
On Thu, Jun 23, 2011, David Lyon wrote: It's not so much that Linux is dead, but rather it is perhaps finished. The computers 'to-die-for' now, are no longer the Windows machines but the Android and Apple computers. .. Apple - linux derivative? Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Article, Linux, APC.
On Thu, Jun 23, 2011, David Lyon wrote: Of course. gnu tool chain, has a command shell... if it has a shell where you can enter linux commands.. it's a linux derivative.. just a very beautiful one.. .. except that it's got a gnu toolchain, but uses chunks of the BSD userland and network stack. There's likely no Linux code in the kernel; or they'd have to release the source. Adrian (I should finish my coffee before posting on the internet.) -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Is Linux Dead a worthy Debate for a SLUG meeting?
I think something to keep in mind (and not because I'm a stickler for such things) is that what's important here is free software. Everything quoted so far leverages free software. Linux is a small part of it. I think the GCC developers may be a bit peeved if all the credit went to Linux rather than them (and the Redhat backing it in the past); similarly with LLVM and all the open contributions being made there. (Yes, that includes by Apple.) It doesn't matter whether Linux dies or not (for value of die), IMHO what matters is that all the free software that makes a useful system useful is still there and ticking along. Adrian On Thu, Jun 23, 2011, Marghanita da Cruz wrote: Linux powers my Motorolla mobile phone, my Kogan netbook, my LED Digital TV and my Webserver. I hope it is not dead. What proportion of Mobile Phones are Android's, I-Phones or I-Pads? Marghanita -- Marghanita da Cruz http://ramin.com.au Tel: 0414-869202 -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: [Jobs] Systems Admin - Build Engineer
On Tue, May 24, 2011, Del wrote: My experience would put that salary at a high level helpdesk person, with what they are asking more towards the 80-100K range. Or am I being somewhat ambitious with my views? No, not ambitious. I had the job pushed at a few people I know by the recruitment agent late last week. They want a degree qualified Linux Admin with extensive development experience as well as able to be a MySQL DBA. When I found out the salary on offer my response was you are joking, right?. +1. The above is basically why I stopped hunting for thos kinds of contracts outside of very narrow markets (eg financial contracts); most (local) places seeking all of the above expect(ed) to pay the equivalent of $60k - $65k pa for it. Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] USB wifi N adapter? With benchmarks?
I've not had any luck with Linux 802.11n in USB form. 802.11n is quite finicky it seems. The atheros 11n adaptors are currently under heavy, heavy development by the ath9k crowd (which includes a lot of atheros employees) so I can only assume that if it isn't stable now, it will get more stable later on. Adrian On Tue, Feb 08, 2011, Dave Kempe wrote: Hey, just wondering if anyone here can recommend a USB wifi for use with Ubuntu Lucid that can do 802.11n and can sustain a decent transfer speed? I am having lots of trouble finding a stable N adapter that actually works at 5.4Ghz. Even a driver family suggestion would be good, as the two atheros cards I have tried have been a disaster. I need current purchasable hardware, USB only cos the boxes are little media centres. -- Regards, Dave Kempe -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Debian/Ubuntu way of having multiple memcached daemon's
On Mon, Dec 20, 2010, Simon Males wrote: I feel like I'm am stepping close to the territory of building my own packages. You are. There's likely some post-install script being run. :-) I suggest looking at what it'd take to make the memcached startup/shutdown script take a -list- of memcached instances to restart, then restart those. That way you can hand that up to the package maintainer so they can include it in a future update. That said, I wonder if there's a way you could create a fake package that just has your restart script, but somehow signifies it relies on the memcached package. Sort of like how library version upgrades signal restarts of daemons. So when you upgrade the memcached package, everything relying on it somehow is also reconfigured/restarted? Or is that a dirty hack done in the libc package itself? Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] dynamically creating a loop device MINOR numbers?
The horrible, O(n) way is to just to loop over 0 .. n, see if it doesn't exist, if it doesn't then create and use it. It's slow, it's racy (ie, don't run the script without locking :-) but it's a traditional UNIX way of doing things. PTYs were once allocated that way, fe. :-) Adrian On Sun, Oct 10, 2010, Zenaan Harkness wrote: If I want to dynamically create loop devices, how would I dynamically create loop device minor numbers in some way, from a shell script, eg.: # setup: UNIQUE_NAME=unique_login_name LOOP_DEV=/dev/loop/$UNIQUE_NAME MINOR_NUMBER=some_hash_or_what_??? mknod $LOOP_DEV b 7 $MINOR_NUMBER chown root.disk $LOOP_DEV losetup $LOOP_DEV /home/$UNIQUE_NAME/source mount $LOOP_DEV /home/$UNIQUE_NAME/target ... # tear down: umount /home/$UNIQUE_NAME/target losetup -d $LOOP_DEV rm $LOOP_DEV Each dyn created loop device will have unique lifetime. So they will be losetup -d'ed at different times, so eventually, the minor numbers will need to be reused. Is there any easy way to do this, whilst creating loop devices with names which I assign, as in the example above? (I began a thread on this a few days ago (and no replies yet), which I will update if you just post here on slug, at http://forum.kernelnewbies.org/read.php?12,2126 ) TIA Zen -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] dynamically creating a loop device MINOR numbers?
On Sun, Oct 10, 2010, Zenaan Harkness wrote: On Sun, Oct 10, 2010 at 2:13 PM, Adrian Chadd adr...@creative.net.au wrote: The horrible, O(n) way is to just to loop over 0 .. n, see if it doesn't exist, if it doesn't then create and use it. It's slow, it's racy (ie, don't run the script without locking :-) but it's a traditional UNIX way of doing things. Think I'll avoid that on principle. Providing a minor # at all seems strange to me. Like Linux should do it. Why do I want or need to know about these MINOR #s anyway?! All I want is an lo dev; far away from this cold nightmare (with apologies to Frederick Loewe). At least losetup is an ELF exe, so if it does the anything similar it should be a little quicker, non-racy, and debugged than my own shell script, notwithstanding statically pre-allocated dev nodes. One can hope :) Well, the binary/kernel may: * loop over /dev/loopX, hoping you've got them there; * do some ioctl on a device (eg /dev/loop), be told a device that's been created for it, and open that * clone the device - eg you open /dev/loop, it creates /dev/loopX and makes your FD map to that I know the latter is what FreeBSD's cloning devices do. That way it's not prone to race conditions. Don't assume that binaries are debugged and work properly. You may find it's only assumed to work in certain, low-frequency-of-use situations. :-) I suggest reading what losetup does to obtain a binary. Pay special attention to ensure if it is looping over /dev/loopX, it actually -is- doing some form of locking. :) 2c, Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Listing local wifi access points?
On Mon, Oct 04, 2010, Erik de Castro Lopo wrote: darrin hodges wrote: The aircrack-ng http://www.aircrack-ng.org/ suit contains a utility that will list AP's. Sorry, any program whose getting started tutorial [0] has a first step of Determine the chipset in your wireless card is going in the wrong direction. I have absolutely no interest in cracking other peoples wifi. What I'd like to do if figure out which channel in my local area is the least congested so I can park my AP on that channel. * get a windows box with a wireless card * grab inssider * run inssider * done/done. Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Listing local wifi access points?
On Mon, Oct 04, 2010, dave b wrote: * get a windows box with a wireless card * grab inssider * run inssider * done/done. ... Yes that works. However, imho the windows part is a real turn off ;) Only if don't already have it installed. :) You know kismet runs on a lot of os's ... http://www.kismetwireless.net/screenshot.shtml .. but having to pick the right monitor mode for the right card just to get it to work was an absolute pain. I finally managed to get it working on my netbook w/ an atheros chipset; but it was fiddly. And I'm -hacking- on the wireless code at the moment. :) (I then just rebooted back into XP mode to run inssider, as all I wanted was RSSIs.) That said, Kismet is great if you want to do detailed wireless debugging. :) It just isn't easy. :) That (all) said, it wouldn't be hard to write a *NIX Inssider clone; it just uses the card-reported RSSI from channel scans. Kismet does a lot more and thus wants monitor/intercept/debugging modes (which is why it's fiddly.) adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] A distro which recognises Wi-fi on Asus eee 1005p?
On Thu, Aug 05, 2010, Jon Jermey wrote: I'm trying to get Linux running from an SD card boot on an Asus eee 1005p but every distro I have tried so far fails to recognise the Wi-Fi (Atheros). Wired connections are working. Does anyone know of a distro which recognises wireless out of the box on this specific model or, failing that, a reliable set of instructions to get one working? You just need to compile the latest wireless-compat source tarball for your kernel. It'll include much more up to date ath9k drivers. I have one of these very-recent atheros chipset eeepc laptops and it works fine. Just need to remember to recompile it every time the kernel is updated. Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: A distro which recognises Wi-fi on Asus eee 1005p?
On Thu, Aug 05, 2010, Richard Ibbotson wrote: On Thursday 05 August 2010 00:54:07 Adrian Chadd wrote: I have one of these very-recent atheros chipset Eeepc laptops and it works fine. Just need to remember to recompile it every time the kernel is updated. Been through that a few times with my EeePC 701 and 1005HA. More recently with Ubuntu 10.04 I find that my 1005HA works fine. It's possible that they've fixed this in the last few days. The kernel upgrade I did last week didn't support it. adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] LVM
You won't be able to. If you configured them up as a stripe (ie, no mirroring) with interleaving every x megabytes on each disk, you'll basically end up with a virtual hard disk with holes evenly spread out across 1/3rd of the image. I don't know of any (easy) tools to recover from that. I can think of what I'd write to try and recover -something- but it'd involve writing a whole lot of rather hairy looking filesystem-scraping code. I'm sure there are tools to do this kind of partial data recovery but they're bound to be -very- expensive. Adrian On Wed, Jun 16, 2010, Gerald C.Catling wrote: Many thanks to all that responded to try to solve this LVM problem. I could not recover any data from the crashed system. I could not find any method of mounting drive 2 or 3 as individual drives and the system would not create a volume group without the now non-existant first drive. Once again, many thanks. I will have to try RAID 1. Gerald -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: LD_PRELOAD
It can be done in code. You can use dlopen() / dlsym() to load in shared objects and their symbols at runtime. Adrian On Sun, Jun 13, 2010, james wrote: On Sunday 13 June 2010 10:00:04 slug-requ...@slug.org.au wrote: I can't find any info on this, so it's prodly so obvious that only dumbkorfs ask :-) I have a program using a web cam. All is perfect except that I need to export LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so before running it. How can I compile the links into the code, rather than a PRELOAD env setting? You can't. Instead, create a wrapper script containing: #!/bin/bash export LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so exec your-webcam-program I do have a wrapper, that does work, so thanks What I was trying to learn is how skype did do exactly that. 2.0 had to be wrapped, but 2.1 (beta) uses the cam without preload. I accept 'You can't' I certainly cant despite trying lots :-) James -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] 500 node mesh network for Parramatta
Speak to a lawyer and find out what the telco licence requirements are? Adrian On Fri, Jun 11, 2010, Richard Hayes wrote: Dear list. Parramatta council is keen on e-government (Don't laugh they are willing to spend money to do it) and minimising the Digital Divide. So, I am proposing to create a Mesh for disadvantaged people. Optus is offering to pay for a number of DSL connection into the mesh but volunteers would design and build the network. Customers would pay a small fee maybe $10-15 per month to get a computer, printer and 1Mb wireless connection. I think a group of the usual suspects, SLUG, Sydney Wireless, Computer Bank etc with some funding from Parramatta could build a 500 node MAN covering lots of Parramatta and give access to many disadvantaged groups. Hardware: Donated WRT54s or Refurbished PCs with Linux Cheap wireless cards with large antenna (7db gain) or Cantenna?? The Council is keen and willing to spend some money but it needs technical help from geeks. Any thoughts / suggestions?? Regards, Richard Hayes 0414 618 425 -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Error in Time() command
On Wed, May 26, 2010, Dion wrote: Martin, That is a very good idea. Thank you! What makes this especially helpful and I'm anoyed I didn't think of it myself, is that an empty app or loop with only the output pulse included, can be used to approximate the overhead of the rest of the system. Effectively giving a potentially more precise measure of the speed of my actual code. That won't be true under a variety of reasons. Two things that come to my pre-caffienated mind is the behaviour of your system when it approaches CPU use saturation and task scheduling isn't immediate(er), and saturation of your memory throughput and/or CPU cache capacity. Both may change the overhead of your sampling method, including the time it takes to run the driver code. An idle system, with nothing else running, may have all of the kernel code needed to handle the parallel or serial port IO (via say, /dev/lpt0 or /dev/ttyS0) needed in L2 cache. Thus when you do the syscall, the relevant code pages don't have to be read in from memory. But when you start loading your system up, the probability of those pages being there stops being potentially close to 1 and starts dropping - and every L2 miss will impact on how long it'll take for the sampling to occur. Note it may not be the -same- overhead each pass as whether those cache lines are available depend on a whole lot of possibilities. Now, these effects (L2 cache/memory throughput) may only add fractions of microseconds of jitter under load. It may be enough for you. Scheduling latencies (more related to system HZ settings, as mentioned previously, but there's more to it than just that) may add considerably more. There's other things that may give rise to variance. If microsecond jitter matters, then another source is TLB (in)validation. Although the TLB isn't necessarily flushed when going user-kernel-user (eg, a syscall, or doing a privileged instruction such as speaking to an IO port), it is at least partially flushed when changing processes. Hazarding a somewhat-caffienated guess, you'd see this has multiple clusterings of jitter deltas, rather than it clustering around one mean. Don't even get me started about what happens when the scheduler decides to change the CPU your process is on - or, which may be more annoying, leaves your process/threads on their CPUs, but scheduling other processes/threads on your CPU from time to time. The behaviour of your sampling overhead may thus change. There's a lot going on under the hood in your hardware. Controlling for all of the variance is going to be tricky. Equating the variances (so you can elimiate that constant part from your work) is going to be even trickier. 2c, and I hope I haven't scared you off, Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Best API/abstraction? [Was: Time Pedantry] servers?)
On Thu, Apr 08, 2010, Del wrote: So which language / library has a great abstraction for time and date stuff, helping you deal with the intricacies of this craziness? Zend Framework (PHP) -- Zend_Date. The date handling functions in PHP are pretty limited but this extension library of an extension library works well. Whatever library the Remember The Milk (www.rememberthemilk.com) folks use is pretty good. I can type in second friday after the third tuesday in november at 4pm and it gets that, and sends me the reminder notice at the correct time even if I tell it I've changed my time zone to Chatham Islands Daylight Savings Time in the mean while. It also understands that repeat every three weeks means 21 days after the event was first scheduled but repeat after three weeks means 21 days after I actually got around to doing it (after postponing it several times). Right, but that's just for parsing dates. But does your code, which uses timestamps for calculation, get one day later correct when DST changeovers occur? When leap seconds occur? Most users/developers only see date parsing and storage as the only issues. There's also date manipulation (eg now plus a day), date comparison, etc. Most developers never have to care about things such as the occasional leap seconds. But this means next day does not necessarily mean current unix timestamp + 86400 seconds and some environments I've been in matter. (Say you're billing thousands of dollars every -second- per client and your clients are happy to sue if you fuck up...) Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Beating the filter
Do your bit to enable end-to-end host IPSEC, rather than IPSEC tunneling. 2c, (and it's half tongue in cheek.) adrian On Thu, Apr 08, 2010, Chris Deigan wrote: On 06/04/2010, at 7:25 AM, Alan L Tyree wrote: Maybe everyone in SLUG already knows how to do this, but I don't. Maybe some kind slugger would write a very short tutorial and we could email it to everyone that we know. There's a dozen different ways, none too difficult to figure out (I have no doubt there's a plethora of sites around with instructions on how to see Facebook from behind corporate filters/whatnot). So many that I've seen, however, give no warning or even thought to the security implications of the methods involved. Realistically, people who wish to bypass the filter usually aren't going to want to pay money to do so; and the general principle for bypassing it is to use a remote system which (a) You can access (b) Is not affected by the filter to relay data on your behalf. The end result: people use whatever they can find for free. I haven't seen much argument to agree with me, but unfortunately I doubt most in the general public might realise the potential for abuse this holds if instructions circulate to the effect of use some random proxy/vpn. Incase it isn't clear, anything you transmit/receive will be readable by the proxying machine. Whether the administrator of that machine will be reading your data is another question entirely, but the concern is that they can. Couple this with how they intend to produce revenue to support such a service (after all, hardware/power/bandwidth isn't free) and such a service becomes even more questionable. So remember kids, evade censorship responsibly. - Chris-- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Solaris is dead. Long live Linux.
On Sat, Apr 03, 2010, Scott Sinclair wrote: Are they now on a 90 day trial, or are existing installs excluded from the whole pay for it change? Either way, I can see pain in my future It's ok; they can migrate their ZFS setups to FreeBSD. Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] SLUG Membership decline
FYI: PLUG has had similar discussions and similar issues. It may be worthwhile having the bodies discuss things informally to see what ideas can be brainstormed. On Fri, Apr 02, 2010, meryl wrote: On Fri, 02 Apr 2010 08:14:03 +1100 jon jonjer...@optusnet.com.au wrote: 1. Make it possible to obtain and renew membership online Yes, I'd become a member if I could do it online or via snail mail. 2. Take advantage of the increasing interest in Linux on the desktop by setting up an Applications SIG and/or focussing on applications at some events. ... So most of the talks and events scheduled by SLUG hold no interest for me. Here! Here! I totally agree, the majority of list of 2009 presented talks appeared to be waaay too techy to entice me to come along and SLUGlets talks appear to be too short to offer anything substantial to take away use. I raised this same issue about a year ago (iirc), I mentioned that LUV's plans for Software Freedom Day http://softwarefreedomday.org/melb looked like a very appealing program of talks and workshops that I'd be really keen to see something like that organised on a regular basis, at SLUG-meets, for us Sydney-siders. * New and upgraded applications demonstrated and discussed * Distros compared and evaluated * Using Linux with various peripherals -- scanners, printers, tablets, multiple screens * Bash programming techniques -- but keeping it simple * OpenOffice techniques and macros * GIMP, Inkscape, Scribus techniques In addition to the above, (a very good list Jon!) I'd also like to see basic/beginning Python, basic/beginning Rails/Ruby, troubleshooting problems; i.e. using run levels, wireless setup etc... cheers, Meryl -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] LAMP - researching setup for hosting on multiple servers
The other thing to think about is whether you need to use an SQL backend at all for this kind of shared data. May web solutions are written using SQL backends and this kind of session persistence because the web site coders / designers don't know any better. Adrian On Sat, Dec 19, 2009, Peter Rundle wrote: Personally I would try to stop using the sessions, and store the client data in the cookie (assuming its not too heavy) your servers are then just a pool of state machines. You can yank any at any time with no loss of service (assuming you take it out of the load balancer first) Yes I agree, I think this is the best solution as the application has so many queries to do on the database in any case before it presents any pages I hardly think that the minimal data stored in the session is worth any speed saving. Then it doesn't matter which server you hit for the next query. If the load balancer is worth anything at all it will auto detect that the server is not there and remove it from the pool automatically. If you have a load balancer that doesn't do this, get a new one. I know its the best way of doing it but that's never appealed to me for PHP, PHP's object orientation and the like have always struck me as hacked on, and cludging it into the traditional 3 tier system just seems to create work rather than save time down the track. I mix my php and html and I'm proud of it ;- I split off into include files commonly used functions and the like but to me PHP is about presenting stuff, It seems silly to have wrappers all over the place. LOL, I mix my html and php too and agree that that is the whole point of PHP it's a template markup language, but I don't put Mysql specific syntax SQL statements in there too, as I think that is bad practice. Better to do spanName:/spanspan?=$member-getName()?/span and $member-getName can get the name value from the database (or the member class can have pre-fetched it and just return the variable contents. Then when you have to restructure your database because you got the entity relationship wrong you only have to change the member-getName method. Also there is good value in using prepared statements such as (select name from member where id = ?, array(this-id)); And these I put in the member data class thus the same php code can run on a mysql database or a postgresql. If you can the best option is usually to have your writes going to one location and then accept reads from another. As most activity on most pages is read intensive you can have your mysql set up with a small pool of multi-master replication or a cluster, and your writes go to there, those are master slave replicated out to either each web server or a distribution server, so all the heavy duty queries get done on those rather than slowing up your database with writes. Yep, all those options become viable once you break the single server dependency. Thanks for your input. Cheers Pete -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] where does postfix store email?
Because it may be storing the inbox folder in /var/spool/mail/${user} or
/var/mail/${user}.
Adrian
On Wed, Nov 25, 2009, Ben Donohue wrote:
Hi all,
yes I know this may seem obvious but I'm scratching my head...
I have email setup as postfix and dovecot for imap.
Email is working fine in and out.
I'm using thunderbird as mail client and the server type is set to imap
mail server port 143.
Now this is supposed to leave all the email on the server, being imap,
isn't it?
If I look in my home folder I see...
drwx-- 3 donohueb donohueb 4096 Sep 18 12:03 .
drwxr-xr-x 5 donohueb donohueb 4096 Sep 16 14:10 ..
-rw--- 1 donohueb donohueb 2827 Nov 25 12:45 Drafts
drwx-- 7 donohueb donohueb 4096 Sep 18 12:03 .imap
-rw--- 1 donohueb donohueb0 Sep 16 14:10 inbox
-rw--- 1 donohueb donohueb 584016 Nov 25 11:16 Junk
-rw--- 1 donohueb donohueb 73968068 Nov 25 12:20 Sent
-rw--- 1 donohueb donohueb 23 Sep 18 12:03 .subscriptions
-rw--- 1 donohueb donohueb 4647947 Nov 25 12:21 Trash
why is inbox zero length and an old date and where is the email stored?
Ben
--
SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/
Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
--
- Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support -
- $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA -
--
SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/
Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: LTS worth anything? (was: Re: [SLUG] Announcement roundup from October meeting)
On Mon, Nov 02, 2009, Robert Collins wrote: Ubuntu LTS gets 6 monthly driver-only updates :). Which can be a good and bad thing. Adrian, who has been bitten once or twice in the past from the driver updates to LTS. Stupid SCSI firmware. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Advice Request for moving a Ubuntu installation to a larger disk and 4Gb RAM
On Wed, Oct 28, 2009, Alan Tyree wrote: That's interesting, Daniel. So what are my tradeoffs. Run the normal kernel: faster but only 2.5gb; Run the bigmem kernel and suffer the performance but have more memory. Hm, does Linux actually -copy- data around when doing PAE? The whole point behind PAE is to give you a larger amount of address space usable by concurrent processes. So each process will have a differently mapped set of PAE RAM pages as needed, along with the shared kernel stuff. I know that FreeBSD will do some data copying to and from devices that are not PAE aware (ie, hardware that only addresses up to 4gig of memory space, and drivers which haven't been converted over) but for individual processes it isn't all that bad. Aside from the work mentioned above, I also edit some really big video files and do ffmpeg transformations on them. Right. In which case 64 bit is for you. So, is there some way of choosing which of the above is the best option for me? I'd suggest trying both out and see. Typically for things like graphics/video editing, I suggest 64 bit almost exclusively now because the programs are written assuming they can hold a lot of data in RAM. Adrian (Who isn't Daniel, but has hacked on a bit of PAE code in his time.) -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] attaching lots of disks to PowerEdge 860?
On Tue, Sep 29, 2009, Dean Hamstead wrote: Take a look at Coraid. These guys made up ATAoE and their disk arrays are surprisingly cheap. http://www.coraid.com/ The last time I read the ATAoE spec, i found it had no real guarantees for data integrity or specifying how to handle packet loss on the ethernet segments. But then, I'm a stickler for this sort of thing.. :) http://www.auspcmarket.com.au/show_product_info.php?input[product_code]=EL-PC-343Binput[category_id]=277 or this much cheaper icute case, of which i have its little brother http://www.mwave.com.au/newAU/mwaveAU/productdetail.asp?SKU=16010594) and then drop in a cheap CPU, a motherboard with a lot of sata connectors and some cheap 4 port sata2 cards. I bought a pair of 5 disk SATA hotplug(ish!) boxes from auspcmarket for experimentation. They work fine enough. The trouble was finding a PC case with sufficient 5.25 halfheight bays which let you mount a half height disk in it. ;) Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] web based firewall config tool wanted
So why not talk tot hem about what would be required, versus trying to craft a whole management ui? :) On Wed, Sep 23, 2009, Grant Parnell wrote: They don't have an openvpn client setup as far as I can tell. That is pfsense and m0n0wall (monowall). Otherwise excellent choice. Adrian Chadd wrote: Uhm, m0n0wall and its decendants? On Wed, Sep 23, 2009, Grant Parnell wrote: I'm finding it difficult to believe there's no simple web based firewall configuration tool. I'm going to be running a cut-down Ubuntu-Hardy off compact flash (read-only root filesystem) with mini-httpd and wish to be able to configure either shorewall or ufw or even iptables directly with a web browser. I can add in the bit that does the OpenVPN client config. I guess for round one it'll be non-customer configurable and I'll just login with SSH and use ufw. I have looked at Fwbuilder and am tempted to go with that. It would essentially push out the configs via SSH and execute them... assuming the unit is reachable. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] web based firewall config tool wanted
Uhm, m0n0wall and its decendants? On Wed, Sep 23, 2009, Grant Parnell wrote: I'm finding it difficult to believe there's no simple web based firewall configuration tool. I'm going to be running a cut-down Ubuntu-Hardy off compact flash (read-only root filesystem) with mini-httpd and wish to be able to configure either shorewall or ufw or even iptables directly with a web browser. I can add in the bit that does the OpenVPN client config. I guess for round one it'll be non-customer configurable and I'll just login with SSH and use ufw. I have looked at Fwbuilder and am tempted to go with that. It would essentially push out the configs via SSH and execute them... assuming the unit is reachable. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Dreamweaver clone for Linux ?
On Thu, Sep 17, 2009, david wrote: So you are suggesting that all those people running Drupal etc are insecure? Just curious, because I'm just setting up a Drupal site for someone. The PHP core has had a few interesting vulnerabilities over the last few years but by and large the available software base is written by people with no understanding of security and it shows. Drupal may or may not be secure. The drupal modules you use may or may not be secure. Etc, etc. :) Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] 40 Years of Unix
On Sat, Aug 22, 2009, Daniel Pittman wrote: Demise?! :-) I have to agree with Jeff: the only places I have really seen the shell vanish it has been moving ??? albeit painfully slowly at times ??? to being replaced by a more powerful programming model, universal scripting. For example, much of the traditional Unix shell use on MacOS has vanished, replaced by OSA and AppleScript, or by Automator. In KDE they are gradually crawling towards more ubiquitous desktop wide scripting. I presume that GNOME is doing more or less the same. So all of these are to do with scripting/automating GUI tasks rather than anything generic. Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] setting up squid proxy
On Tue, Aug 18, 2009, Ben Donohue wrote: Any clues or doco on where to start first? I have an internal DNS server so all squid should have to do is lookup the correct address and forward to that. You can do it a multitude of ways. The easiest way is this: http_port 80 accel defaultsite=www.cacheboy.net vhost act-as-origin visible_hostname mirror3.us.cacheboy.net # Since all requests must go via a cache_peer, don't ever allow # direct forwarding. Make sure your cache_peers (which are origin servers) # don't allow forwarding (ie can act as proxies too!) never_direct allow all # allow requests from everyone http_access allow all cache_peer michelle.cacheboy.net parent 80 0 no-query originserver login=PASS name=www.cacheboy.net no-netdb-exchange no-digest cache_peer_domain www.cacheboy.net www.cacheboy.net cache_peer_domain www.cacheboy.net none That says: * port 80 is a http accelerator, with a default site listed, a virtual host and acts as a HTTP origin * the visible hostname of the proxy is X * don't ever go direct to the internet - ie, you must use a cache_peer to satisfy a request * allow requests to everyone * define a backend parent server which is an origin server; pass auth details to it; don't query it for cache digests, ICP, etc * map www.cacheboy.net into it Or have I got something wrong here. Nope. The documentation just sucks. :) Adrian Any pointers appreciated. Thanks. Ben -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] where to get an Ethernet hub (NOT a switch)
On Sun, Jul 19, 2009, Amos Shapira wrote: 2009/7/19 Matt Hope matt.h...@gmail.com On Sun, Jul 19, 2009 at 09:36, Amos Shapiraamos.shap...@gmail.com wrote: I'm looking for an Ethernet hub to be used for network troubleshooting (trying to find which of our hosts is involved in the load on our office uplink). Would something like this be useful instead? http://www.enigmacurry.com/articles/building-an-ethernet-tap/ Yes very much. Now I have to find a way to build it since I don't have the resources (tools, time) to do it myself. Doesn't this break the relevant electrical specifications for ethernet over twisted pair? :) It may work, but ethernet certainly isn't intended to work this way. Who knows what the side effects will be. Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] The growing size of programs
On Sat, Jul 04, 2009, pe...@chubb.wattle.id.au wrote: Does anyone have suggestions for a low-memory setup? As far as web browsing goes, you're stuck. There's no money to be made working on low footprint browsers and noone in the academic/open source community has picked up on the handful of fledgling, lightweight browsers and updated the rendering models to cope with modern stuff. X windows is increasingly suffering from the same issue. There's plenty of abstraction layers between the application itself and the rendering engine(s), a lot of them assume computers with accelerated hardware and/or fast memory to video display busses. Throw the same code on something with an ISA-era graphics card and you can -watch- things draw. When I first started using Unix (1979), we were on a PDP11-70 with 32 to 64 simultaneous users --- with 256k of real memory. I'm still doing the same sorts of tasks: reading and writing email and news; writing and typesetting documents, and programming. My *mobile* *phone* has more grunt than that machine --- let alone my laptop, even the old one I've been describing. I suspect there's a lot of bloat in there somewhere. Welcome to 2009. :) It is only going to get worse. Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Ubuntu friendly 12' netbook
My experience with the acer aspire one running XP has been one of pleasant happiness. I'm not a normal user though; I install very little extra software on my user machines. Now to get Linux/Xen and FreeBSD working on it.. Adrian On Tue, Jun 09, 2009, Kyle wrote: My only one experience with an Acer laptop has left me with the impression; I will never buy another Acer laptop. I can't quantify it, but it has effectively been slow since the day it was bought. Granted it runs MS, but it was always slow. Kind Regards Kyle Voytek Eymont wrote: I have no idea if Acer does Linux, BUT, (as I'm also on a netbook research for someone (though, with XP)): there is a new Acer out with 11.6 and 3g slot: btw, is there a site with Linux netbook compatibility ? -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Problem viewing articles in Slashdot ( Optus Cable )
On Sun, May 31, 2009, Jesus Jr M Salvo wrote: 4) Using wireshark, I can see that I get a TCP RST during after the HTTP GET is sent. This started happening yesterday. I let it pass thinking it might be a fluke, that maybe someone else will complain and it will be all fixed by today. However, I am still experiencing the problem. So I am thinking that it maybe related only to Optus ? That sounds like a busted load balancer or webserver to me. It could also be a busted squid proxy at Optus. If only Optus would talk to me about Squid support services, stuff like this wouldn't happen... :) Adrian - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Lenovo wins $150m NSW schools deal or April Fools joke?
On Mon, May 18, 2009, Marghanita da Cruz wrote: So, the school kids are being taught to develop content for four colour industrial printing, rather than websites? Personally, I would think that school kids and FOSS developers time is better spent improving tools and adding to content in the online world. What really erks me, is that no doubt a PDF newsletters will be produced and emailed around to be printed on home and school printers (no commercial printer in sight). - Tell me I'm wrong. I'd rather they'd be taught the difference between the two, so hopefully those who are smart enough to get it will have the oppertunity to. Don't dumb stuff down. Kids are smarter than you'd think. And god knows that FOSS developers could do with being exposed to stuff -outside- of the cool+hip FOSS environment(s) today. Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] HOT SWAPPING - Internals of the sync/umount call
On Sat, May 16, 2009, Grahame Kelly wrote: Rather than stating what I suspect is just a belief, have you look at the Kernel source code at all? If so I would be very interested at exactly where you state such activity happens. According to Linux Internals Doco (and hereijn I refer to the Linux Drivers themselves) Once the device has been un-mounted the OS warrants that the device, its linked control blocks, buffers etc. are indeed-flushed and data secured on the device medium. The applicable driver HAVE already unloaded any cache data before the umount command returns with its resultant response. And I assume that you 100% believe that when the drive says YES SIR I HAVE SYNCED it has actually done this? :) I have never experienced this in all the years working with Linux. Either you haven't un-mounted the device correctly (that is checked the return status byte if in a script), or the OS release you refer to is/was buggy, Or you've been lucky! FWIW, SATA devices are hot-swap and the are ... a little less than 8mm of coverage for those connections. Just sayin' SATA I, II and forthcoming III specifications originally covered hot- swapping. So it would be expected at the hardware level. Its optional. And it is not always implemented correctly. I have some notes somewhere from some previous experiments with various desktop-y SATA chipsets under FreeBSD/Linux and I found that they didn't all do hotswap as advertised. ;) Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] hot swapping hard drives
Uhm, I'm reasonably sure there's more to hot swap than the physical and electrical connections. I'd thus do a little more research on the topic (like reading the datasheet(s) for your motherboard and SATA chipset) to ensure that the hardware supports it. There also may be a requirement for you to manually tell the OS to detach and attach disk devices. Adrian On Sat, May 16, 2009, Grahame Kelly wrote: Hi David. As long as the drive in un-mounted you can safely remove/insert a device. You just need to make sure the drive Power connections allow hot-swapping, but generally you will get away with it normally if you haven't such PSU plug h/w. Just be aware that your PSU will require better surge power - so if your current PSU is a bit iffy, it will probably fail in time has been my experience. Hope this helps. Cheers. Grahame From: david da...@kenpro.com.au Date: 15 May 2009 11:58:14 PM To: slug@slug.org.au Subject: [SLUG] hot swapping hard drives I've just installed a sata hard drive bay for a second drive, the kind that has a little front door so you can slip the drive in and out. The point of installing it was to make it easy to change drives when doing backups, but I had assumed that I would have to shut down before taking the drive in or out. When I unmount it, Gnome announces that I can now remove the media, which surprised me a bit. Should I assume that this means I can safely hot swap this drive as long as it's unmounted? The nice man in the shop assured me that I needed all sorts of mobo magic to be able to do that, but of course he was talking Windows. I would hate to splat 500G of backup. Thanks, -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] recovering xfs
And what is being logged in dmesg? Your kernel should be spewing a whole lot of error messages if your physical media is returning errors. Adrian On Thu, May 14, 2009, fos...@tpg.com.au wrote: Problem dd sat and looped on a single point last night. I have downloaded a statically linked version of dd_rescue and I am now trying this. Fingers crossed. ssh r...@server '/root/dd_rescue /dev/vg1/lv1 -' | cat /dev/vg1/lv1 It is coming up with this error though: dd_rescue: (info): ipos: 34031.5k, opos: 34031.5k, xferd: 34031.5k * errs: 7, errxfer: 3.5k, succxfer: 34028.0k +curr.rate:11628kB/s, avg.rate: 149kB/s, avg.load: 0.1% dd_rescue: (warning): /dev/vg1/lv1 (34031.5k): Invalid argument! -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] recovering xfs
On Thu, May 14, 2009, fos...@tpg.com.au wrote: Still working on this, the whole thing appeared to lock up and we have rebooted.We have now replaced a drive in the raid and hopefully this will work better. Of course this is going to take ages to rebuild. lets hope you don't throw another disk during the rebuild with all of that parallel IO going on. :P Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] dns attack
Yes. See recent NANOG mailing list archives. On Tue, Jan 27, 2009, Alex Samad wrote: Hi I was wondering how many other people are getting flooded with named[29134]: client 63.217.28.226#17705: query (cache) './NS/IN' denied dns DDOS attacks ? -- Mr. Vice President, in all due respect, it is--I'm not sure 80 percent of the people get the death tax. I know this: 100 percent will get it if I'm the president. - George W. Bush 10/18/2000 St. Louis, MO During the third presidential debate -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [Fwd: Re: [SLUG] IOWait definition]
iostat can be a bit special.I -think- under linux its the amount of time spent waiting for pending disk IO to complete. Now, some chipsets and their drivers seem to spend a lot of time in IOWAIT compared to others. The traditional difference was polled vs dma'ed disk IO - with polled IO, the driver would submit a request and then sit there and wait for it to complete. That time spent waiting was IOWAIT. DMA'ing controllers would spend less time in IOWAIT because they'd submit a request, kick it off, it'd happen in the background, and then the kernel would be notified when it completed. Almost no time was spent in IOWAIT - just the time scheduling the DMA commands and handling the response. Now, I've seen some low-ened SATA chipsets on some reasonably speccy hardware (eg some of the nvidia-driver Sun workstations) with large amounts of IOWAIT time. I don't know if its a driver thing or a hardware thing (or both), but there are definitely issues. Now, you could go groveling through the kernel to try and figure out whether IOWAIT includes nfs activity (which I believe would be the disk IO related to NFS, but it could be other things I guess) and first see if doing userspace disk IO does a lot of IOWAIT. Grab bonnie or some other hard disk throughput testing thing, run it, and see how much time is spent in IOWAIT. If you've got almost no IOWAIT time when doing it locally but IOWAIT time when doing it over NFS, you could be right. If you have IOWAIT time on both, I'd poke the disk/controller/ driver combo. 2d, Adrian On Thu, Oct 09, 2008, David Kempe wrote: Grant Street wrote: I have a machine with a good proportion of IOWait 20-30%. It does have local disks and it performs operations on NFS mounts. I just wanted to be sure if IOWait includes NFS activity or not. I also want a way if it is NFS to be able to say for sure if it is a bottleneck on the nfs client or server. NFS is not a linux machine so visibility is not allways the best. dstat might help you correlate stuff. http://dag.wieers.com/home-made/dstat/ dave -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [Fwd: Re: [SLUG] IOWait definition]
On Fri, Oct 10, 2008, Adrian Chadd wrote: Now, you could go groveling through the kernel to try and figure out whether IOWAIT includes nfs activity (which I believe would be the disk IO related to NFS, but it could be other things I guess) and first see if doing userspace disk IO does a lot of IOWAIT. Grab bonnie or some other hard disk throughput testing thing, run it, and see how much time is spent in IOWAIT. If you've got almost no IOWAIT time when doing it locally but IOWAIT time when doing it over NFS, you could be right. If you have IOWAIT time on both, I'd poke the disk/controller/ driver combo. I just re-re-read the OP and stuff and realise my assumptions don't match your request. I assumed you wanted to know if IOWAIT included disk IO time -and- nfs server time. But you're asking if IOWAIT include NFS client time (ie, time spent on your box talking to the NFS server.) Anyway, doing a bonnie++ or such test will still tell you. Run it locally and run it over NFS. See if you get IOWAIT increases for both. That should give you some hint as to whats going on. I've never seen IOWAIT for NFS client traffic (ie, traffic from an NFS client talking to an NFS server) but who knows, this is linux.. adrian 2d, Adrian On Thu, Oct 09, 2008, David Kempe wrote: Grant Street wrote: I have a machine with a good proportion of IOWait 20-30%. It does have local disks and it performs operations on NFS mounts. I just wanted to be sure if IOWait includes NFS activity or not. I also want a way if it is NFS to be able to say for sure if it is a bottleneck on the nfs client or server. NFS is not a linux machine so visibility is not allways the best. dstat might help you correlate stuff. http://dag.wieers.com/home-made/dstat/ dave -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Choosing a sensible host
I also offer commercial VPS/hosting services; you can get ssh access to the virtual web server group if you ask very, very nicely. I've also capped bandwidth costs so you don't get turned off or charged excess if somehow you go over. Adrian On Mon, Sep 22, 2008, Dean Hamstead wrote: maybe try http://www.bur.st/ Dean Mary Gardiner wrote: On Mon, Sep 22, 2008, Jim Donovan wrote: Can anyone suggest a better host which also allows SSH logins? http://www.anchor.com.au/ is a SLUG-friendly Aussie company that has SSH logins. Dreamhost is a widely used US company and costs US$6 per month. They have had 'incidents' in the past with uptime, but most people seem quite happy. http://www.dreamhost.com/ If you'd actually prefer something more server-like, then http://www.linode.com/ has US-based virtual servers for US$20/month. -Mary -- http://fragfest.com.au -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] DODO
On Fri, Aug 29, 2008, Haw Loeung wrote: yeah I ran into the TPG proxy admin at my local woolies (overheard him talking to someone about it and had to interrupt!) He said they are running squid on rhel4 I think. He didn't say what version, but I got the impression it wasn't actively being upgraded. squid-2.7.STABLE3 on CentOS 5.2. Last updated Squid in July 2008. Have you patched it with Steven Wilton's transparency hacks to handle non-HTTP crap on HTTP ports? Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] DODO
On Wed, Aug 27, 2008, Lindsay Holmwood wrote: Unfortunately TPG have a *very* broken transparent HTTP proxy. Trying to work around it's bugs is a nightmare for web developers (I know, i've been there). I wonder if they're still using Squid.. (Squid's much better at transproxying these days.) Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] /var/run too small - how do I change it?
On Thu, Jul 17, 2008, Daniel Pittman wrote: Like ramfs it grows on demand, with a cap, rather than preallocating space. ramdisk is a reasonably inaccurate description of it, really, because this is a purpose built ram backed filesystem rather than emulating a block device. In fact, I'm reasonably sure its meant to be more like a swap backed FS which just -happens- to be cached in RAM. I used to configure very minimal swap on machines w/ large amounts of RAM - why bother with lots of swap? If the app server has to start paging then performance will bottom out very quickly! - however then tmpfs'es started showing up in Linux and these want more swap space so long-held temporary files don't hold up precious RAM. 2c, Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Linux and other software made in India... and lessons we can't understand...
On Fri, Jul 11, 2008, [EMAIL PROTECTED] wrote: but you gotta give it to them, they have done wonders with software and computers... You really may be surprised if you saw where Australians ended up in technology companies. such a pity our political leaders aren't actually smart enough to figure out how they have done it but they don't mind spending our hard earned money on some wining and dining and partying to try to figure it out Damn those politicians. Its obviously their fault and not the fault of the people who elected them in the first place! Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Hyperthreading
On Fri, Jul 04, 2008, Rev Simon Rumble wrote: I have an Intel Xeon 3 gig CPU and have hyperthreading turned on in the BIOS. I've been trying to work out what the advantages and disadvantages of this are. ok. The CPU appears as two CPUs to the machine, which means that non-threaded apps don't appear to use the whole CPU. Is this a correct assumption? For example, using Devede to convert video, the transcode Yes. process only uses 50% of CPU in top. If I run another CPU-intensive process, the CPU usage in top goes close to 100%. Yes. So would I be correct in assuming that hyperthreading is useful for keeping the system responsive under load, but if running single-threaded CPU-intensive processes, it'll run faster without hyperthreading? Mostly. You need to understand what hyperthreading is. Imagine you can break up your CPU into building blocks. You've got logical control blocks, integer math blocks, instrution execution blocks, all that kind of jazz. You won't be using -all- of the execution blocks all of the time - code is generally not 100% optimised and isn't keeping the whole CPU busy. 100% CPU usage on a single code/thread is actually not 100% of the CPU is busy, its There's no way to do any further work without causing some of the work to sit in a queue and wait. Hyperthreading is a way to make two threads of execution share the same building blocks. The two threads can then try and do more work by using the blocks unused by the other. Whether its faster or slower depends on your kind of work. Some kinds of work involves keeping almost all of the blocks busy - adding a second thread and trying to run other jobs actually slows both of them down. For example (and I apologise for becoming technical) - if you have blocks A,B,C,D, and your job involves work being done on A+B and the results being consumed by C with all of the blocks staying active (ie, you don't have A+B doing work, then they sleep whilst C does some work, then C sleeps whilst A+B does work) then your CPU may show up as 100% busy even though block D is sitting there idle. If you introduce a second thread via hyperthreading and it wants A+D to do work, then you've got a problem - thread 1 wants to fully use A+B+C but every time the second thread wants to do work it wants A+D and A can't do twice the work :) So whenever thread 1 is running (A+B+C) then thread 2 can't run; whenever thread 2 is running (A+D) then thread 1 can't run; this shows up as both CPUs running at 100% but results in less work being done. Some kinds of work involves keeping only a few blocks busy - adding a second thread allows more work to be done without interfering with each other. Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: 6 comm ports ?: [SLUG] more RS232: USB-RS232, PCI ?
It depends on which card you're using. If you're using a card that exports lots of 8250/16450/16550 chips then sure, the default serial driver only tries to probe 4. Lots of multiport serial cards have their own driver, do their own thing and aren't supported by the PC serial driver; they have different restrictions. Adrian On Fri, Jun 27, 2008, Voytek Eymont wrote: On Fri, June 27, 2008 6:57 pm, Jobst Schmalenbach wrote: http://www.verbatim.com.au/technotes/Linux_S.txt this says, inter alia: Since Linux only support 4 serial ports (ttyS0, ttyS1, ttyS2, ttyS3) under the default condition. Most likely, ttyS0 ttyS1 are supported by mother board's built-in serial controllers and ttyS2 ttyS3 are free for additional I/O card. so, if I have 2 ports on main board, what will I need to do to get 6 ports in total ?? -- Voytek -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Is someone is snooping my wireless?
On Tue, Jun 24, 2008, Daniel Morrison wrote: I have never understood that whole don't broadcast your ESSID thing. Security by obscurity, surely? I had one place in dim memory that implemented that specifically so arbitrary devices wouldn't associate-by-passing and tie up valuable slots on their WAP. Read, too many associations, AP blows up.. Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] : Increasing filesystem reliability (was : Filesystem which allows online fsck?)
On Thu, Jun 12, 2008, Erik de Castro Lopo wrote: In the above situation we are seeing machines have difficulty when coming up after a powerloss. I suspect that we end up with problems that even Ext3's journalling isn't enough to cope with and I suspect that its actually the loss of disk metadata which is causing the problems. [snip] Does anyone have anything else to suggest? Invest in small UPSes and cleanly shut the server down on shutdown? Can you enable entire journalling, rather than just metadata journalling? Can you disable write-caching on the disks, so the disks aren't lying when they say they've committed some stuff to disk? I seem to recall there are brands of disks which will go to great lengths to lie to you that the data is on the disk when its still in cache, all in the name of (windows) performance. Its funny, as the whole argument with the ext3 journalling block device versus the XFS journalling was to work better on PC-class hardware. (Ie, when you don't have enormous PSU Capacitors and an NMI which get triggered on power-loss, giving you just enough juice to tell the disk controllers to -STOP- and not scribble random crap over important metadata sections. God, where'd that email get to?) Adrian (Anyone remember why Linux ext2's defaults versus BSD FFS's defaults were so bad?) -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: Compromised Linux box stories (Re: [SLUG] upgrading complicated installs)
On Mon, Jun 02, 2008, Jeff Waugh wrote: Yet there are so many who go nuts when the idea of accreditation is raised. :-) [This cheap shot does not indicate my support for or against the idea!] Heh. They don't suspect the real issue with accreditation? That suddenly Universities will have to teach a real CompSci and Software Engineering degree, and that degree will probably be 4 or 5 years long, including internships and honours-level project (mandated like the Electronic/Electrical engineering degrees seem to here at UWA); because Writing Good Software is Hard ? Ah, if only writing software held the same risks and building bridges. :) Adrian (Who should really get a CompSci degree from a reputable CompSci university sometime.. anyone know any?) -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: Compromised Linux box stories (Re: [SLUG] upgrading complicated installs)
On Mon, Jun 02, 2008, Michael Lake wrote: Adrian Chadd wrote: Ah, if only writing software held the same risks and building bridges. :) It does. Here is the classic: http://en.wikipedia.org/wiki/Therac-25 http://catless.ncl.ac.uk/Risks/3.09.html This dates from way back in 1986. Oh yes, there are specific areas like this where screwups kill people. I meant writing software in general. Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: Compromised Linux box stories (Re: [SLUG] upgrading complicated installs)
On Mon, Jun 02, 2008, Rick Welykochy wrote: Daniel Pittman wrote: [2] formmail. I say no more. The perl language has been pretty bullet proof. I do recall one string-based exploit in the many many years I have been using it. Shit code can be written on all platforms. That said, yup, scripts like formmail are written by monkeys in the 11th level hell and sent to torment sys admins. I was running an ISP and in my early days I stupidly allowed some customers to upload their own perl CGI scripts to our (only) main web server. After watching the machine being brought down to its knees due to inexperienced coding (don't ask) I learnt my lesson very quickly. They only way to allow user-supplied scripts nowadays is via some sort of virtualisation scheme with solid sandboxing. Even then, poor coding can gobble up heaps of resources needlessly. The trouble is that the entry barrier for coding is so low, you can code without any clue. Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] opening com port in terminal
On Tue, May 27, 2008, Voytek Eymont wrote: suspecting that perhaps the com port might be faulty, I've rebooted the PC with Knoppix 4 CD, and, Knoppix's minicom (after configuring) reads all 4 sensors correctly (even if still says 'off line') but, when I reboot with centos (with sensors still plugged in), I get nowhere as far as I can see, both centos' and knoppix's minicom are set same .. and you've compared dmesg's and such to see if the serial ports are being identically detected and registered? Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Easy way to duplicate a setup?
.. setup a scripted install using your favourite distribution. (It has hooks to do that, right?) .. get PXE booting working) (Your hardware PXE boots by default, right?) adrian On Mon, Apr 28, 2008, Alex Samad wrote: On Mon, Apr 28, 2008 at 12:51:47PM +1000, DaZZa wrote: OK guru's. :-) I'm in a situation where I need to duplicate on a mass basis - to the order or 3000-5000 units - a Linux setup off a headless box. All the destination boxes will be identical in specification, and the same as the original. At this point (trial - only 15 to do), I've made an image of the disk using DD to a USB attached drive - which works, and gets the new boxes working, but takes 3+ hours to dump the image back to the new boxes. 3+ hours over 5000 machines is not really acceptable. :-) Is there a better way to do this? Something which will make a smaller image and dump back quicker - most of the disk is empty, there's only about 15 gig of actual data/setup on a 160 gig drive - and still maintain the partition setup/bootability like using DD does? Willing to listen to anyone who has a cluestick and is willing to apply it. buy a disk duplicating enclose (or hardware raid/swraid ) and use it to duplicate drives Thanks. DaZZa -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- Natural gas is hemispheric. I like to call it hemispheric in nature because it is a product that we can find in our neighborhoods. - George W. Bush 12/20/2000 Washington, DC -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] uptime and multicore/multithreaded cpu's
On Thu, Apr 24, 2008, Andrew Cowie wrote: He had such a bad time of trying to explain latency to senior IT that finally he gave up and hacked the kernel so that it reported artificially high load averages to trick out the external monitoring agents so the IT managers wouldn't feel that they could lump more services onto the box, thereby increasing their utilization at the cost of completely destroying responsiveness. Thats why Squid reports service time statistics for request lifecycles.. :) Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] working wvdial.conf file for Vodafone Huawei E220?
Argh. not more HSDPA. (I've just spent last week hacking on stuff for Maxon BP-3 modems). Good! Maybe you'll know where to snaffle a datasheet or two to help me hack up something to send/receive SMSes from *NIX ? Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] SIM cards as cheap data storage?
Uhm, I'd check the bulk prices of small flash drives (256meg); you might find you can pick them up cheaply. A cute hack I saw recently (from telstra!) was to use a USB uC to pretend to be a CDROM storage device to store a few hundred bytes of a pretend ISO CDROM. This way autorun.inf was run, and IE was spawned. :) Adrian On Tue, Apr 15, 2008, Sridhar Dhanapalan wrote: I am looking for a cheap data storage solution for many people. The requirements are as follows: * CHEAP (very important) * storage space isn't important - maybe a couple of hundred kilobytes max. * media can be lost and replaced without much trouble/cost * media can be easily read/written by an ordinary Linux computer * media and media reader must be reasonably durable * scalable: the media should be distributable to millions of people Flash memory is too expensive - I'm looking for cards that cost $1 each. I was thinking that SIM cards (like what you get in your phone) would fit the bill. Is it possible to use these as a generic storage medium? All the information I could find on USB SIM card readers mention that the SIM is accessed as a serial rather than a storage device. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] SIM cards as cheap data storage?
On Tue, Apr 15, 2008, Sridhar Dhanapalan wrote: On 15/04/2008, Adrian Chadd [EMAIL PROTECTED] wrote: Uhm, I'd check the bulk prices of small flash drives (256meg); you might find you can pick them up cheaply. I mentioned that the media needs to be less than (or very close to) $1 each, and that I don't even need 1MB. When you say SIM are you referring to the radio SIM, or are you including smart cards? Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Network Real-Time Hot Filesystem Replication?
On Sun, Apr 06, 2008, Amos Shapira wrote: I've been using DRBD for a few months now (just in stand-by mode, but been following the forums and docs during that time) and all indications are that: 1. You CAN'T mount a non-cluster-aware file system even read-only on the secondary node since the primary will change FS-structs under the feet of the read-only node and cause it to crash (because non-cluster-aware filesystems assume that they are the only ones who touch that partition). 2. You CAN mount read-write on multiple nodes if you use one of the cluster-aware filesystems (GFS and OCFS are regularly mentioned, but if you find any other cluster-aware file system then it sounds like it will work too). IIRC they assume a single back-end device. Does DRBD give you a journaling block device which will stall updates until they've been pushed? How will the FSes tolerate the device IO being possibly milliseconds later than the master? Have you tried this suggestions? From all I read about DRBD this will cause all secondary nodes to crash. I looked into it about a year ago and I couldn't find any simple way of doing this using free software. There's CODA/AFS as possible solutions but they still push the notion of master/slave rather than equal peers, which Chris mentions he needs (ie, constant synchronisation between each member rather than periodic pushback..) Chris, try looking at CODA/AFS support? Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Auntie excludes us
On Thu, Mar 13, 2008, Rev Simon Rumble wrote: This one time, at band camp, James Dumay wrote: Perhaps this would make a good open source project to produce a player (and perhaps the backend services) needed for Television stations to distribute their media. More likely, reverse-engineer where the streams are coming from, how they're presented, and build an alternative front-end in a cross-platform manner. .. or people could just accept the fact that, for now, flash video is the thing and dumping resources into the fledgling open-source flash toolkit (whatever its called) is probably the best short-term bet. I vaguely remember hearing h323 container support into flash popping up so a flash player can just pipe data into hardware rather than doing the (bulk of the) decoding itself but I'm just not on top of any of that technology. Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] [ot] cheap sms?
Is there any reason you can't use a *G dataplan to fire off the data versus SMS? At 10c a SMS you're up for a $6k bill each month. At 160 bytes a transaction (normal SMS length), 2000 a day is roughly 300 kilobytes uncompressed. * 31 days is ~ 10 gig of data. Maybe with compression you could squeeze that 2:1 into a data plan for (hopefully far, far under) $50 a month. Just a thought, Adrian On Tue, Mar 11, 2008, Richard Hayes wrote: Dear list, I am doing remote telemetry with a small linux box (of course) and then using sms to transfer the data. Can anyone recommend a supplier of cheap sms for large quantity? Within a few months 2000 per day. regards, Richard Hayes 0414 618 425 begin:vcard fn:Richard Hayes n:Hayes;Richard org:Nada Marketing adr:;;PO Box 12 ;Gordon;NSW;2072;Australia email;internet:[EMAIL PROTECTED] tel;work:+(61) 2 8669 9835 tel;fax:+(61) 2 9327 4908 tel;home:+(61) 2 9436 0121 tel;cell:0414 618 425 x-mozilla-html:FALSE url:http://www.nada.com.au version:2.1 end:vcard -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] [ot] cheap sms?
On Tue, Mar 11, 2008, Martin Visser wrote: On Tue, Mar 11, 2008 at 12:52 PM, Adrian Chadd [EMAIL PROTECTED] wrote: At 160 bytes a transaction (normal SMS length), 2000 a day is roughly 300 kilobytes uncompressed. * 31 days is ~ 10 gig of data. ^^^ ~ 10 Meg me thinks Oops, didn't group reply; 160*2000 32 160*2000*31 992 What did I do wrong? Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] [ot] cheap sms?
On Tue, Mar 11, 2008, Phil Scarratt wrote: 992 is in bytes Yeah I just noticed that. My bad. Still, 10 megabytes @ 19 cents a megabyte is still a lot cheaper than the cost of 2000 messages. It just means you can do it over GPRS versus going for a current-generation 3G dataplan.. Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] hard drive failure, back-up, and other unhappiness
External drives are ok for me as long as it has some Raid on it (at least Raid 5). Single drive backup is like an optical backup with a lot of rewrites ;-) (I should really be replying to the OP, but ..) Of course, the -sensible- method of doing it is to cycle through backup media, rather than having an active and backup disk set. All you need is one bad backup and everything is toast - or, in my case (which didn't hurt me as I -have- lots of backup disks that I swap in once a week into my enclosure, as well as hourly/daily/weekly incremental tarballs going off-site) lightning damaged the fileserver and the currently active full backup going to the external disk. Both were very charcoalled :) (Yet another problem solved thirty years ago that people keep reinventing..) Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: Wireless problems: what does RX too short data frame payload mean?
On Wed, Mar 05, 2008, Mary Gardiner wrote: Looks like it might be their problem, right now. I'd still like to find out what causes the RX message, as my disk has to wake up all the time to write it out to the logs. There's at least a minimum frame size in Ethernet; I'd not be surprised if Wireless Ethernet had similar restrictions. Encrypted sessions generally pad frames out so the original packet size can't be gleaned. ISTR even WEP did this. Just find the line and insert a NUL character or NOP instructions appropriately ?:) Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Oracle 9i database and samba
On Thu, Feb 28, 2008, Simon Wong wrote: Hi all! Can anyone confirm whether Oracle 9i running under Windows will work if it's DB files are stored on a samba share? I have to try and run Mincom's Minescape under Windows but want the data and DB shared via Samba. .. why do you think this would be a good idea? Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Oracle 9i database and samba
On Fri, Feb 29, 2008, Simon Wong wrote: .. why do you think this would be a good idea? because the instance of Windows will be running under VMware server (or Workstation) and I like to keep the data outside the VM where it can also be shared with other instances of the app. What are you thinking? That I'd be asking Oracle and your application vendor whether your proposed setup is fully supported. Backending databases onto random network attached storage is a very bad idea unless you Know What You Are Doing; and if you're on here asking then you probably don't fall into that category. The other poster who runs Oracle off a netapp filer is surprising to me, as I've had no end of issues with databases on network attached storage, but -my- experiences haven't been with Oracle on Netapp NFS, just MySQL on Linux NFS. In any case, knowing what I know about the wildly different flavours of NFS implementations, I'd not be putting a critical SQL DB on it (or heck, even hash tables with shared writers!) unless my vendor told me it was ok. In short: Ask your vendors. Thats what you're paying them for. :) Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Oracle 9i database and samba
I think I phrase the question incorrectly to start with. If I just want one instance of the Oracle DB (the Design File Server) can I run it installed in a VM and have it's DB files stored on Samba shared to it from the host OS? Again, why are you asking here versus the two vendors in question? I strongly suggest you just ask your vendors and get them to sign off on it. I sincerely doubt anyone here is qualified to tell you yes or no; and Minescape looks like a serious piece of mine design and operations planning software. Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Asus Eee 4G 7 Micro Laptop
On Wed, Feb 27, 2008, Martin Visser wrote:
And right on cue, here comes my employer's eeePC killer -
http://www.engadget.com/2008/02/19/hps-umpc-2133-revealed/
You have to wonder though whether in 10 years we have really come that far -
http://www.hpmuseum.net/display_item.php?hw=233 . The sub-notebook category
all but dissappeared and now it seems to be back with a vengeance.
Google for libretto PC and picturebook PC - I hope this resurfacing is
as successful (but brings better software!) than the Apple Newton - Palm Pilot
-
{Windows CE devices} - {Mobile Windows CE devices} path.
Adrian
--
- Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support -
- $25/pm entry-level VPSes w/ capped bandwidth charges available in WA -
--
SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/
Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Asus Eee 4G 7 Micro Laptop
On Fri, Feb 22, 2008, Martin Visser wrote: There were dozens at LCA last month - geek envy abounded. They seem very solid. The Linux Action Show guys did a pretty thorough review in their latest podcast - http://www.linuxactionshow.com They are quite amenable to installing other distros if you don't like the default ( boot off a SD card if you want) Compiz apparently works a treat. It seems this form factor (and capability) is neatly filling the gap between regular notebooks and PDAs that tablets and UMPC have failed to fill. I'd be pretty confident that they other main vendors will be quickly trying to come up with competition. (And no, even though I work for one of them - I have no inside knowledge - I have only been watching the public ruminations) I like them. Its going to be my eventual replacement of my old sony picturebook, which exists in the same form factor. That form factor is surprisingly useful in all kinds of places. Now, if only you could fold the screen all the way back over the keyboard and read books on it.. :) Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re. Am I dumb??? or is Debian still better than Ubuntu?
On Wed, Feb 13, 2008, Adam Bogacki wrote: Re. Am I dumb .. etc. Nope. You've just seen the light. I tried ubuntu but went back to Etch .. then sid/lenny .. because it gave me more flexibility between text GUI and access to more interesting software. Nothing beats the original. I've had no trouble with ubuntu. I just do the server install, install ssh, then things just work. My only beef with ubuntu right now is that the 7.x Xen support is actually broken compared to debian etch, and has been since sep 2007. For some reason hwclock on debian hangs hard when running under ubuntu, but the debian shipped version doesn't seem to have this issue. Of course, both have issues with the default xen example configs and udev, but thats a different beef. :) Adrian (who runs Xen VMs for about 25 geeks now, and has had a pretty wide exposure to Xen under lots of distributions..) -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Am I dumb??? or is Debian still better than Ubuntu?
Why are you downloading the desktop image? Why not install the server image? adrian On Tue, Feb 12, 2008, Richard Hayes wrote: Dear list, I want to setup a server so remote users (ie brother in-law) can access a box with Aussie IP address. Currently foreign IPs can not assess eBay Australia he sells lots of stuff through eBay. So, I downloaded the 7.04 Ubuntu desktop image and burnt it to a CD. Then I tried to install it on an old Compaq box but I don't have spare mouse to use the desktop stuff. Tried three old ones but no success. After 30 mins of stuffing around I could not do anything without a mouse so I decided to download the 32M cd image of Debian and configured the box in 2 mins. The download of all the software will still take another 2 hours. But I found in much easier to manually configure the box than use the automatic stuff. How many other people prefer the text setup rather than graphical system?? Am I dumb or what?? regards, Richard Hayes 0414 618 425 begin:vcard fn:Richard Hayes n:Hayes;Richard org:Nada Marketing adr:;;PO Box 12 ;Gordon;NSW;2072;Australia email;internet:[EMAIL PROTECTED] tel;work:+(61) 2 8669 9835 tel;fax:+(61) 2 9327 4908 tel;home:+(61) 2 9436 0121 tel;cell:0414 618 425 x-mozilla-html:FALSE url:http://www.nada.com.au version:2.1 end:vcard -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Data Leakage Prevention and Detection
On Tue, Feb 12, 2008, Barrie Hall wrote: I've always seen this as an HR issue, not a technical issue at all. Employee signs a contract which says don't send our documents outside without permission, don't take sensitive stuff out of the office on a USB stick, etc, etc, if you do and we catch you we will dismiss/warn you. Catch someone, make an example of them, problem solved!! The stakes are higher when the data is worth quite a lot of money. Corporate espionage is a reality.. Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Data Leakage Prevention and Detection
On Tue, Feb 12, 2008, Rev Simon Rumble wrote: This one time, at band camp, Adrian Chadd wrote: ideally you want your data security right down to the individual syscall level. Various products like what Cisco offer let you specify what access to what data various applications have, but i don't know how useful it is protecting people from copy/pasting data around. I know at least the secure versions of IRIX and Digital UNIX were doing useful things like tagging individual IPC data with security ACLs, preventing you from copy/pasting between high-low security contexts. That was fun to work inside. :) But the nice security vendor man installed a box on our network and gave me a certificate that promised we were secure! :) Adrian -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Data Leakage Prevention and Detection
Thats why you don't do it like this. Well, you do this, but only as part of the solution. ideally you want your data security right down to the individual syscall level. Various products like what Cisco offer let you specify what access to what data various applications have, but i don't know how useful it is protecting people from copy/pasting data around. I know at least the secure versions of IRIX and Digital UNIX were doing useful things like tagging individual IPC data with security ACLs, preventing you from copy/pasting between high-low security contexts. That was fun to work inside. :) adrian On Mon, Feb 11, 2008, Jamie Wilkinson wrote: This one time, at band camp, Ricky wrote: - first, you classify data Eg.engineering.doc is commercially sensitive or customer_creditcard.xls is personal privacy - setup rules in your DLP, likely to be an appliance box sitting behind the firewall - stops data from going out the LAN Application-aware firewalls are time consuming to develop, but I am concocting in my mind a tool that scans signatures out of all your documents, then has a tcpdump running on your firewall comparing traffic signatures -- sort of like snort, but in reverse -- and sending TCP RST to the sender if a violation was detected. I can also think of ways around it (SSL, for example, is a trivial workaround, so you'll need to also MITM all your users... a wildcard certificate ought to fool the client browsers). Do things like this really exist?? Well, I imagine Lotus Scrotes could, because the document never really leaves the database, but how would you build a system that reliably worked in a heterogenous environment like a small-medium office, that actually worked, and you could sell to people and still retain your soul? -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Data Leakage Prevention and Detection
Its not a difficult problem with a real security model. You'd be able to say stuff like USB ports are low security level; and documents in these groups can be copied | documents in these groups can't be copied | etc. Unfortunately operating system vendors push crap security models from the early 90s as its backwards compatible with expectations, and you end up with lots of third party applications to fill in the gaps, with reasonable amounts of success. Adrian On Tue, Feb 12, 2008, Rev Simon Rumble wrote: This one time, at band camp, Martin Visser wrote: I tend to think that such devices are probably more security theatre as Bruce said it in his keynote, as it is hard to do reliably. If you allow users adhoc access to mail or web browsers, while you can catch sequences of numbers like 1234 if you are watching for credit card numbers, are you watching for one two three four, onetwothreefour, eentweedrievier and I,II,III,IV as well? This is simple encryption that people can easily detect, but with modest obfuscation are possibly hard for automated systems to correctly detect. In order to effectively limit data leakage I think you need :- Indeed, and I bet these places still have active USB ports on their PCs. To resolve this problem reliably takes a real systematic approach. But the snake oil vendors push security as product, not process. I would think that some kind of watermarking would be a better approach, so that each version of a sensitive file is striped in some way on checkout, so at least you can track who circulated the file. Of course watermarking can be defeated. Then again, the dodgy dossier used to justify the Iraq war by the British government still had tracked changes accesible, showing the changes to the official intelligence made by Blair's spin doctor. -- Rev Simon Rumble [EMAIL PROTECTED] www.rumble.net The Tourist Engineer Geeks need vacations too. http://engineer.openguides.org/ In politics, what begins in fear usually ends in folly. - Samuel Taylor Coleridge -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Asynchronous Distributed Filesystem
Under Linux? DRDB? http://www.linux-ha.org/DRDB/ On Wed, Jan 16, 2008, Joel Heenan wrote: SLUG, We have a requirement in a new project to have a distributed filesystem. Files are written to one of 32 * 200MB volumes and we need to keep them in sync with a DR site. Rsync, I believe, will be just too slow to replicate changes - unless there is some way to make the rsync daemon hook into the kernel and know what changes have been made? RHEL GFS I think will not work across such differences and won't do it asynchronously. unionfs is I think too experimental. Continous Access, using our SAN to replicate the data, at this point has to be discounted because of licensing. How do other people generally solve this problem? Thanks Joel -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Asynchronous Distributed Filesystem
On Wed, Jan 16, 2008, Joel Heenan wrote: Hi, In response to Adrian I'm looking for a solution that will work well under RHEL. I hate to say it, but you bought RHEL, so ask Redhat. Thats part of the benefit of buying a product with support - you can ask their engineers what will work well and then go to them when you have trouble. :) -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: [activities] If you could ask Microsoft a question, what would it be?
On Mon, Jan 14, 2008, Melissa Draper wrote: You're going to throw lab rats at them?? I wanna watch. Don't lab rats suffer enough? Seriously, if you get someone from Microsoft in to talk about something and you start hounding them with questions about FOSS, making them feel awkward and generally not wanting to be there, then they'll probably not want to come back. adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Question on pixels.
On Tue, Jan 08, 2008, [EMAIL PROTECTED] wrote: Is there a command that tells you the dimensions of your monitor in pixels. Yes. Sometimes. :) I've asked around and received some extraordinary responses, including 1. Of course not, what a fatuous question. 2. Dunno, the dimensions are a function of the refresh rate. 3. Dunno, but it can't be a constant, because I read somewhere that the pixels can be stretched. Wow. ok, 1 is a stupid answer; 2 is somewhat true. 3 is almost true, but its more due to how CRTs work and how LCDs pretend. :) This last one threw me, but I think it meant that a single pixel can be replaced by, say, four of the same character (= stretched). Can anyone give me an answer? Sure. Background time. LCDs? There are discrete pixels, which are then broken up into RGB elements. You don't get more or less pixels; although some monitors do something called interpolation which is a fancy way of taking resolution X and mapping it onto a larger resolution Y, figuring out what the colour/intensity of the pixels in between should be. Google for it, there's probably better descriptions out there. In short with LCDs: don't rely on interpolation to give you -any- great colour images; its just there for the times where the graphics resolution != the native LCD resolution (eg, when the BIOS is starting up the computer.) Now, there's a funny way that graphics cards interface with some monitors and can ask politely for information. I think its called DDC. CRTs? CRTs, especially monochrome ones, don't have a specific resolution per se. Its just an electron beam scanning over the phosophorus in the front of the monitor, and that phosphorus is what displays the picture. The resolution depends on a few things: * there's generally a granularity to the phosphorous, so if you make the beam too narrow you end up with bleeding between pixels; * there's generally some kind of metallic mask sitting there somewhere, which limits the resolution in one or the other direction; and * colour monitors (which I guess you're thinking about!) do have discrete pixels at least in one direction (horizontally or vertically); again, google for how colour CRTs work to get an idea. * And finally, yes, the refresh rate does affect the CRT resolution. Next - refresh rate. Its a fun one. refresh rate affects CRTs by just overtaxing what the electronics and the tube itself can do. Refresh rates can limit LCD resolutions by trying to push too much data over DVI. DVI has a fixed upper speed and doesn't fail gracefully like VGA (read: blurring and artifacts.) This is why you need 1 DVI connector to drive those enormous apple monitors - because one DVI connector couldn't support the data rate needed to drive that resolution at the refresh rate. Ok, so enough of the background. There's this funny protocol called DDC. Its a plug and play type protocol, which generally means pray that everything supports it right. It lets a VESA-compatible VGA card probe the monitor for its capabilities. Under Ubuntu there's a package called read-edid. It installs 'get-edid' and 'parse-edid'. Here's what it shows for my setup, a dual-head radeon card with a VGA and DVI LCDs. One monitor didn't report anything, one monitor reported its info. The monitors are recentish, and this PnP protocol has been around since mid last century iirc, so its probably a quirk somewhere.. [EMAIL PROTECTED]:/var# get-edid | parse-edid parse-edid: parse-edid version 1.4.1 get-edid: get-edid version 1.4.1 Performing real mode VBE call Interrupt 0x10 ax=0x4f00 bx=0x0 cx=0x0 Function supported Call successful VBE version 200 VBE string at 0x0 ATI RADEON 9200 VBE/DDC service about to be called Report DDC capabilities Performing real mode VBE call Interrupt 0x10 ax=0x4f15 bx=0x0 cx=0x0 Function supported Call successful Monitor and video card combination does not support DDC1 transfers Monitor and video card combination supports DDC2 transfers 0 seconds per 128 byte EDID block transfer Screen is not blanked during DDC transfer Reading next EDID block VBE/DDC service about to be called Read EDID Performing real mode VBE call Interrupt 0x10 ax=0x4f15 bx=0x1 cx=0x0 Function supported Call successful parse-edid: EDID checksum passed. # EDID version 1 revision 3 Section Monitor # Block type: 2:0 3:fd # Block type: 2:0 3:fc Identifier L1910S VendorName GSM ModelName L1910S # Block type: 2:0 3:fd HorizSync 30-83 VertRefresh 56-75 # Max dot clock (video bandwidth) 140 MHz # Block type: 2:0 3:fc # Block type: 2:0 3:fc # DPMS capabilities: Active off:yes Suspend:yes Standby:yes Mode1280x1024 # vfreq 60.020Hz, hfreq 63.981kHz DotClock
Re: [SLUG] Let the UMPC wars start :)
On Mon, Jan 07, 2008, Alex Samad wrote: Is 512M really enough memory ? Yes? What target market is it targetting again? Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] linux filesystem
On Wed, Jan 02, 2008, Alex Samad wrote: sounds like xfs it is then .. of course, you could benchmark how it performs, you could try a few things, like pull the power out whilst you're working on stuff and see how jfs, xfs and ext3 hold up. (Personal experience: xfs was nicer to use, ext3 is pretty nice nowdays compared to the rest and seems to handle bad power on consumer disks w/ no battery backed up RAID much better than the others. But this was all from my own personal experimenting from about 5 years ago; I'm not sure if things have changed substantially since then.) Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [LINK] Re: [SLUG] Looking for expertise/guidance on Linux/satellites/small form boards
On Sat, Sep 29, 2007, Howard Lowndes wrote: Thanks Peter, there is some good meat there esp about the TCP tuning. I am aware of the latency involved with geostat sats, but for data transfer that would not be a major issue, whereas it would be a significant issue if voice were to be incorporated. On the other hand, low orbit sats would redce the latency but would also enable uptrans (and downtrans) only within certain windows. Satellite VoIP is possible. You just need to know what you're doing. (And accept 500ms RTTs..) Adrian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
