May 2016 - Talk - lists.gtalug.org

Netgear 5-port Gigabit switch -- $10 ?
by William Park 05 Sep '16

05 Sep '16

Canada Computer is selling - Netgear GS105E ProSafe Plus Switch, 5-Port Gigabit Ethernet - 5 Ports - 5 x RJ-45 - 10/100/1000Base-T - Wall Mountable - http://www.canadacomputers.com/product_info.php?cPath=355&item_id=077172&ut… for $10. Any comment on the item? -- William

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War Story: for want of a nail...
by D. Hugh Redelmeier 20 Jun '16

20 Jun '16

(Actually, for want of a nylon post, but that's less poetic.) Only read this if you are interested in an example of hardware debugging. An older desktop, acting as a MythTV server, started crashing hard. - would start to reboot, get past POST, but didn't get all the way up. - didn't seem to be software because the spot that it stopped was not consistent. It would even crash while I was in grub trying to edit the kernel like to show more boot logging. - Power supplies are often the problem. My tester said all the voltages were there (but of course that's a pretty coarse test). - Often contacts stop conducting as well as they used to. Oxidization? Unplugging and plugging in all the RAM, cards, and devices did not fix anything so that probably was not the problem. - Then I notice the heat sink on the nvidia FeForce 8200 chipset was askew. And something was loose in the bottom of the case. Here's a picture of the motherboard: <http://www.ecs.com.tw/ECSWebSite/Product/Product_Detail.aspx?DetailID=873&M…> The heatsink in question is orange, near the top right. There are two nylon posts that hold the heatsink against the chip (see the white spots on opposite corners of the heatsink?). The one post had perished and let go. Probably slightly explosively since between the head of the post and the heatsink is a spring (a bit like the spring in a retractible ballpoint pen). When I touched the still-functioning post, it broke too. I figured the computer's behaviour was consistent with the chip overheating. I didn't know how to source the right nylon replacement posts. Instead, I used a pair of pairs of cable ties. I used some 20-year old thermal grease (hey, I seemed to have bought a lifetime supply back in the day). I first scraped off the one-time phase-change thermal pad that had been used. I was happy that my jury-rigged computer seems to be functioning correctly now.

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Used computers
by Tim Tisdall 06 Jun '16

06 Jun '16

Where's a good place to get a used computer for relatively cheap? I have a uncle who's struggling with a fairly old machine (I'm not sure what it is, but it has a CRT monitor) and I was hoping to replace it with something slightly newer. Maybe someone knows a good spot to get off-lease computers? What does UofT do with their hand-me-downs?

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Network down after reboot
by William Witteman 01 Jun '16

01 Jun '16

I recently rebooted my Debian desktop, and there is no working network now. Networking has "just worked" for so long that I am at a loss as to what to do. I haven't changed /etc/network/interfaces in forever, but ifconfig -a shows that eth0 is not being configured, and if down eth0 confirms it. I tried fiddling with the Network Tools thing in Gnome, but it hasn't changed anything. Did I miss a change to how this is done and need to learn a new approach? Thanks!

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looking to identify two books in these images
by Dave Cramer 31 May '16

31 May '16

The white book in this one. http://beaver1.fastcrypt.com/~davec/book1.png the orange book in this one http://beaver1.fastcrypt.com/~davec/book2.png Dave Cramer

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pigs with wings
by D. Hugh Redelmeier 29 May '16

29 May '16

I'm going to do the unthinkable: throw out a working notebook tomorrow. An NEC Versa SX from 1999. Running Fedora Core 1. Pentium 2 @ 233MHz 256M of RAM 10G HDD [an upgrade from something considerably smaller] Video: Trident Cyber 9388 Screen: 1024x768. No built-in networking (that's what PCcards are for). Swappable bay for CD writer and floppy drive (I have both). Came with a Windows NT 3.5 license (if I remember correctly). but with Win98 installed. The video is a problem: it is only "TrueColor": 16 bits/pixel. The X driver has a long-standing bug where at each power-on the video might be in a state where the colours are screwed up. The only cure is to power cycle. The fundamental problem is that X doesn't know how to fully initialize the device. Kind of 50/50, if I remember correctly. I'm playing with it now. The screen is bright and clear. I quite like the feel of the keyboard. There is a constant fan noise. The machine was quite nice for its day but things are mostly better now. I bought this 17 years ago, lets say 8 doublings by Moore's law. Current nice notebooks vs this: RAM: 16G (2^6 better) SSD/HDD: 256G vs 10G (2^5 more capacity but a lot faster) HDD/HDD: 2T vs 3.2G (2^10 more capacity and a bit faster) screen: 3200x1800 vs 1024x768 (2^3 better) CPU: 2.4GHz vs 233MHz (2^3 faster clock but more instructions/second too) So: Growth is impressive but Moore's law doesn't seem to have applied.

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Printing Problem - Can't find printer
by Stephen 27 May '16

27 May '16

I am using Ubuntu 14.04 Printer is Epson WF-2630 Wi-fi connection. Hard coded IP address When I try to print, I get a Gnome pop-up saying printer is off-line. Using the web interface to CUPS the reported error is printer not found. I can always ping the printer. I can always print from a windows computer on the same network. I can, from the CUPS web interface "modify" the printer settings. I click through without changing anything. When I am finished, the stalled print job is printed. Any ideas how I can print without "modifying" the printer settings? -- Stephen

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Metapackages for "security testing" ?
by William Park 27 May '16

27 May '16

Does anyone know any Ubuntu metapackage names for security auditing and testing? I'm currently downloading Kali (Debian based) and Backbox (Ubuntu based) to be installed on VM later. But, it would be nicer to "apt-get install xxx". At the moment, I don't know what "xxx" might be. -- William

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NVidia GTX 1080 annoucement
by William Park 24 May '16

24 May '16

Howdy, I only caught the last 30min of the live stream. Made me wonder... Is there way to use its 2560 GPU cores as substitute for the usual 4 CPU cores? -- William

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example of why RISC was a good idea
by D. Hugh Redelmeier 22 May '16

22 May '16

<https://software.intel.com/en-us/articles/google-vp9-optimization> Intel describing how they improved the performance of the VP9 decoder for Silvermont, a recent Atom core. The meat is several not-really-obvious changes to the code to overcome limitations of the instruction decoder. The optimizations seem particular to Silvermont but the article says: Testing against the future Intel Atom platforms, codenamed Goldmont and Tremont, the VP9 optimizations delivered additional gains. These optimizations did nothing for Core processors as far as I can tell. I don't know if it affects any AMD processors. A RISC processor would not have a complex instruction decoder so this kind of hacking would not apply. I will admit that there are "hazards" in RISC processors that are worth paying attention to when selecting and ordering instructions but these tend to be clearer. Another thing in the paper: The overall results were outstanding. The team improved user-level performance by up to 16 percent (6.2 frames per second) in 64-bit mode and by about 12 percent (1.65 frames per second) in 32-bit mode. This testing included evaluation of 32-bit and 64-bit GCC and Intel® compilers, and concluded that the Intel compilers delivered the best optimizations by far for Intel® Atom™ processors. When you multiply this improvement by millions of viewers and thousands of videos, it is significant. The WebM team at Google also recognized this performance gain as extremely significant. Frank Gilligan, a Google engineering manager, responded to the team’s success: “Awesome. It looks good. I can’t wait to try everything out.” Testing against the future Intel Atom platforms, codenamed Goldmont and Tremont, the VP9 optimizations delivered additional gains. Consider 64-bit. If 16% improvement is 6.2 f/s, then the remaining 84% would be 32.55 f/s. Not great, but OK. For 32-bit, 12% is 1.65 f/s; the remaining 88% would be 12 f/s. Totally useless, I think. Quite interesting how different these two are.

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