Wikipedia:Reference desk/Archives/Computing/2014 February 7

src: upload.wikimedia.org

February 7

Video Wikipedia:Reference desk/Archives/Computing/2014 February 7

blocking a malicious website

I use Windows 8.1, updated. I run Malware Bytes Pro and Windows Defender. When I go to some websites (Amazon, etc) with Firefox (updated), Malware Bytes says that it has blacked a malicious websites - 162.210.192.22, 162.210.192.26, and sometimes another one I haven't been able to write down (the message disappears too quickly). Sometimes on IE (current) I can tell that it is trying to connect to something else, but it is being prevented from doing that.

On a lot of web pages when I'm using Firefox, after the page loads, the big green arrow moves up to the download arrow in the upper right corner, as if it is downloading something.

I ran a full scan with Malware bytes and it removed 46 things. I ran complete scans with Windows Defender and Microsoft Safety Scanner - the found no problem. I ran Malware Bytes again and it didn't find anything.

Some sort of malicious software has gotten on my system, and I can't get rid of it. Any ideas?

Also, sometimes two jiggling popups saying "browser extension available" pop up in fFirefox. When that happens I close the browser. Bubba73 ^{You talkin' to me?} 03:36, 7 February 2014 (UTC)

You may well need to run several other tools to get rid of the problem. bleeping computer has a good list. Each tool finds some infections but not others. If you have problems you can start a thread on thier forums and someone will walk you through the process.--Salix alba (talk): 10:27, 7 February 2014 (UTC)

I would first try a clean reinstall of Firefox.--Shantavira|^{feed me} 10:36, 7 February 2014 (UTC)

I seem to be having a similar problem with IE. I don't get a message, but the url flashes several times as if it is trying to connect to another website. Bubba73 ^{You talkin' to me?} 17:40, 7 February 2014 (UTC)

I uninstalled Firefox and did a clean install. So far I haven't gotten the Malware Bytes message about trying to connect to malicious websites, but in the tab in the upper left it flashes several times, back and fourth between the website I want and something else I can't read (too fast). So it appears to be trying to connect to something else. I'm also getting strange, suspicious popups. I updated Firefox and Thunderbird 3 days ago and the problem started after that. Bubba73 ^{You talkin' to me?} 18:05, 7 February 2014 (UTC)

I'm getting help from BleepingComputer. No progress yet. Bubba73 ^{You talkin' to me?} 02:54, 8 February 2014 (UTC)

Yes it can take a few days. They will get round to you.--Salix alba (talk): 11:22, 8 February 2014 (UTC)

I got one message bask within a few hours, asking me to run FRST and post the log, which I did. No reply since then. But thank you for telling me about the site (Bleeping Computer). Bubba73 ^{You talkin' to me?} 21:14, 8 February 2014 (UTC)

Maps Wikipedia:Reference desk/Archives/Computing/2014 February 7

Buying refurbished computers?

What are the pros and cons of buying a cheap refurbished computer like these? Are they any good? (I have in mind just doing fairly simple stuff like running R and LaTeX and browsers.) Michael Hardy (talk) 18:28, 7 February 2014 (UTC)

I have bought three refurbished computers, with good results. One was directly from the Dell Outlet store, for $259. Last year I bought two refurbished quad-core i5s - both from eBay, I think - less than $400 each. I needed to add some memory to both. So I've had good results, but these are not my primary computer. Bubba73 ^{You talkin' to me?} 19:05, 7 February 2014 (UTC)

Personally, I would let all friends and relatives know that you need a second-hand computer. You will probably get one then for nothing. To refurbish: Use the vacuum cleaner and a fine brush to remove the fluff from the CPU heat sink etc. Replace the motherboard battery with a fresh one [1].Also, maybe purchase a lens cleaning lens cleaning disc for the DVD drive. Reinstall the operating system. Also R & LaTeX can be run on Linux so no necessity to reinstall Microsoft. [2] So, no antiviral software to buy each year (or you can down load 'free copy' of avast!). Refurbished units are usually ex-business machines which have been heavily used, so the hard-drive is coming to the end of its life. A refurbished machine is a lot to pay for when it requires no skill to do it oneself. --Aspro (talk) 19:08, 7 February 2014 (UTC)

src: wiki.cancerimagingarchive.net

Scalers?

The article VMEbus includes an image with a "scaler" module. I've encountered these before but never been able to work out exactly what a scaler does in this context or where the term comes from. Any ideas? --Amble (talk) 21:28, 7 February 2014 (UTC)

When I see that word my first thought is that it's a typo for "scalar". But I don't know. Michael Hardy (talk) 21:32, 7 February 2014 (UTC)

Don't think it's a typo, see wiktionary entry 1 here [3], and this WordNet definition here [4]. It seems that there should be a WP article on this. Pretty sure that the VMEbus isn't doing video scaling, but I can't tell if it's doing pulse counting, signal aggregation, or both... SemanticMantis (talk) 21:46, 7 February 2014 (UTC)

Thinks... The VMEbus can carry video right?! So what I remember as the up-converter is now called the Video scaler. So the Etymology is that the module 'scales' up the screen resolution. Have a horrible feeling that some ex-spert is going to shoot this down in flames but as of now it makes sense to me.--Aspro (talk) 22:02, 7 February 2014 (UTC)

The model number in the photo is V830, specs here [5]. In this context it's doing some kind of pulse counting, but I don't understand where the name "scaler" comes from or how (whether) it's different from simple pulse counting. --Amble (talk) 22:07, 7 February 2014 (UTC)

Googling around. AV Tools still recognise the term up-converter. [6]--Aspro (talk) 22:14, 7 February 2014 (UTC)

A scaler is a lot like a blitter except it can resize. Fancy ones will provide math to anti-alias; really fancy ones can do transposes and rotations; very advanced scalers like the ones inside a GPU can perform full affine transforms. In one way or another, these are all DMA engines - very special processing units that do very specific jobs asynchronously from the main control CPU. These hardware units can be used by any sufficiently-skilled programmer for any software task that comes up - but mostly, the applications relate to image processing and DSP-style math.

And here, excerpted from GPU Gems - which every computer engineer should read! - is Texture Bombing, a technique to cheat your performance constraints: you can make a very low resolution texture appear very high resolution by dithering its position and scale stochastically. A programmer might push state matrices in OpenGL or call "StretchRect" in DirectX,and allow the hardware device driver to operate the GPU's scaler unit behind the scenes (the hardware scaler call in that example-program hides inside of the "tex2d" implementation, provided you have an Nvidia device).

Or, if you write software on a modern Unix supercomputer, you might use CoreAnimation and set up Core Graphics' CGAffineTransform math. For example. you could make a scaling transformation. All that spits out is a tiny data structure - four or nine floats, or something like that! You pass those to a function, and an image appears on screen, and it's been scaled correctly. Now, if you run your code on a Mac or a NeXTCube or an iPad, you'll see that the image still gets scaled - and each computer has selected the best possible way to do that scaling - maybe it multiplies and interpolates every pixel in a software for-loop. Were one to (hypothetically) design a power-efficient, 64-bit battery-operated hand-held supercomputer, one might spend a lot of effort to make sure that the scaling occurs with minimum energy impact - ergo, using no CPU or GPU cycles at all - by building that sort of software-API directly into a unique and efficient piece of hardware. Hypothetically. Nimur (talk) 17:35, 8 February 2014 (UTC)

Thanks, Nimur, but I believe the image scalers you're referring to are a completely different item from the VMEbus scaler module I had in mind. --Amble (talk) 16:40, 9 February 2014 (UTC)

It's a piece of equipment used in high-rate, high-accuracy data acquisition applications, including particle physics equipment like hodoscopes and wire chambers, used in part to sort through the torrents of real time signal that pour from detectors and extract some useful content from them. Some basic description of the operation of binary and latching scalers is here, and some idea about how these devices, together with other high-speed electronics, can be composed to produce a useful processing system is in this paper (p17). -- Finlay McWalter?Talk 18:41, 8 February 2014 (UTC)

Well, maybe thirty years ago it was a dedicated piece of rack equipment, or an expansion-card in a general-purpose computer... or maybe even an analog circuit! But today, it's more common to use a digital signal processor; or if using a general-purpose computer, to use a high-resolution data acquisition card (like one from National Instruments), and a GPGPU or a powerful CPU for any real-time data-processing. I'd be really interested to see if any current lab-grade data acquisition products are splitting this basic functionality into a separate piece of equipment! For example, no such device is in the LeCroy product line-up today! Even my WaveRunner, which is at least fifteen years old, has digital (software) gains. The actual work of scaling - whether it's 1-D signal or 2-D images or 3-D geometric models - is now done in software, or in a microscopic digital circuit deep inside a DSP processor. Nimur (talk) 21:53, 8 February 2014 (UTC)

Thanks, Finlay McW. Yes, that's what I was looking for. I have worked on a project that used scalers, but they had been set up quite some time before and I never touched the scalers hardware. --Amble (talk)

Source of the article : Wikipedia