Wikipedia:Reference desk/Archives/Computing/2017 January 10

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January 10

Memory use by R (programming language)

Is R's memory management less efficient than other languages like Java or Python? The R (programming language) article could use some expansion around this issue. --Hofhof (talk) 12:30, 10 January 2017 (UTC)

This is a very difficult topic. R is primarily used for complex mathematical calculations. Most people work with vectors and add/remove objects in the vectors many times. R uses malloc to reserve memory. Doing so for each item added to a vector would make R deathly slow. So, R reserves large chunks of memory and then internally manages the memory in the block. To over-simplify it, R requests a big chunk of memory from the operating system, even if it doesn't really need all of it. Then, R reserves/releases memory inside the block itself. The entire block is always reserved by R from the OS perspective. So, you can say that the memory management is better suited for what R does since it is handled by R. You could also claim that the memory management is wasteful since R reserves more memory than it will use. In my opinion, it is not proper to compare memory management in R to memory management in Java or Python because you are comparing two radically different things without even getting into the specifics of exactly how R's memory management works. 209.149.113.5 (talk) 18:28, 10 January 2017 (UTC)

Websites for asking questions from certain nationalities

For example I'm trying to identify a music video that's probably German or Austrian and I thought maybe I would have a higher chance of people identifying it for me on a website frequented by German or Austrian people. I've found www.gutefrage.net but I'm looking for more.

I'm also looking for a website where I can reach Czech people to identify a probably Czech movie. I've found http://www.csfd.cz/ but it one of those sites where you have to have a certain amount of points before you can post so I can't use it.

Languagesare (talk) 14:35, 10 January 2017 (UTC)

• [1] seems to be the de WP equivalent of our reference desk. I cannot read Czech but you can try to find a similar page.

If you meant that you want to ask in English I am out of ideas. (Sweden has this but that is not exactly what you had in mind.) Tigraan^{Click here to contact me} 14:57, 10 January 2017 (UTC)

You could ask, in English, there. Just as we sometimes get foreign language Q's here, I'm sure somebody will be able to translate there. StuRat (talk) 17:27, 10 January 2017 (UTC)

Thanks, I did that. Languagesare (talk) 19:19, 10 January 2017 (UTC)

Scroll speed in Chrome vs IE

I'm visiting my father and he's asked me to look at something on his laptop. It's an Asus X540S running Win10.

The issue that he's asked me to look at is that in IE, his two finger scroll on the trackpad will move the page at an acceptable rate. In Chrome however, it is very quick! He, at first, was telling me that it just snaps to the bottom of the page, though it doesn't. It's just so quick that his older eyes couldn't quite catch it. It's even so fast that I would find it annoyingly quick and I have much more dexterity in my fingers than he does.

I think that slowing it down system-wide would be fine but I can't find a way to do even that. Is there a way to slow it down system-wide or more specifically in Chrome? 50.244.0.245 (talk) 17:32, 10 January 2017 (UTC)

I suggest looking into the Chrome addon "Chromium Wheel Smooth Scroller" or one of the many variants. It adds a lot of scrolling settings - which includes how many lines to scroll and how fast to do it. 209.149.113.5 (talk) 18:21, 10 January 2017 (UTC)

I've noticed that on Wikipedia that some pages with a large amount of information take a long time in IE before it will do any scrolling whereas Chrome doesn't have that problem. Bubba73 ^{You talkin' to me?} 18:23, 10 January 2017 (UTC)

The Chromium extension doesn't do anything for the trackpad. I'm not seeing other options for the trackpad... Other ideas? 50.244.0.245 (talk) 20:55, 10 January 2017 (UTC)

double the number of CPUs by an option

This video says that CPU chips have twice the number of advertised cores for spares if some of them quit working. Is this true? Is it safe to do this? What happens if one of the cores dies after you do this? Does this increase the size of the memory cache too or leave it the same? Bubba73 ^{You talkin' to me?} 18:21, 10 January 2017 (UTC)

I have not watched the video. Your description is not accurate. CPUs do not have spare cores laying dormant, waiting for the active core to fail. If you don't know much about computers, you might think that you have double the cores in a CPU by using various tools to inspect the CPU. As an example, I have a rather old computer. It has two quad-core CPUs. That means that it has 4 cores per CPU and 2 CPUs for a total of 8 cores. If I look at the CPUs through the operating system, I see 16 cores, not 8. That implies that there are 8 cores on each CPU, not 4. Of course, there are only 4 cores. The CPUs have hyperthreading enabled. Each physical core shows up as two logical cores to the CPU. I can turn off hyperthreading and see only 8 cores if I want (I don't want to). In the end, you simply need to know what you are doing and what you are looking at. 209.149.113.5 (talk) 18:36, 10 January 2017 (UTC)

The video description begins: "NOTE - This video is a joke..." Dragons flight (talk) 18:38, 10 January 2017 (UTC)

Whoops, I didn't see that warning. Bubba73 ^{You talkin' to me?} 19:00, 10 January 2017 (UTC)

Resolved

The important part of user:209.149.113.5's reply is that the 8 logical cores on the real CPU each support hyperthreading, and (to some extent) behave as 16 core. LongHairedFop (talk) 20:07, 10 January 2017 (UTC)

Yes, I know about that. Three of my current nine desktops have hyperthreading. Bubba73 ^{You talkin' to me?} 21:39, 10 January 2017 (UTC)

But note that some mainframes (e.g. IBM zSeries) do indeed often have more cpus than sold and available to the customer. They can be activated remotely if the customer buys an upgrade. Apparently, it is cheaper to always ship the hardware than to build different versions and occasionally go through a real hardware upgrade. --Stephan Schulz (talk) 22:34, 11 January 2017 (UTC)

Some CPUs allow you to enable/disable cores, with proper firmware (e.g., BIOS/UEFI) support. Also, CPUs can be sold with things that are physically present but faulty or disabled by the manufacturer. CPUs can be sold with a locked CPU multiplier. Chips that have a fault affecting only part of the chip may be sold with the faulty portion disabled; for instance, if a defect affects only one core, it can be sold as a CPU with fewer cores, rather than thrown away. As mentioned above, this particular video may be a joke, but there's some basis in reality for similar things. --47.138.163.230 (talk) 04:06, 12 January 2017 (UTC)

Also another thing that came to mind later: fancy, expensive "enterprise" hardware can support all kinds of things, like multiple physical CPUs and hotswapping of CPUs, not found in your average consumer device. Systems where high availability and reliability are required, such as banking and finance, industrial equipment, control systems on vehicles, medical equipment, etc. frequently feature multiply redundant components, including CPUs. In such systems you can often have backup CPUs which are normally idle, there to take over if a primary CPU fails. --47.138.163.230 (talk) 11:30, 12 January 2017 (UTC)

Folder Locking Software

Require a folder locking software that opens up a security window to enter password whenever I click on the ‘folder’, something like the ‘BitLocker’ drive locking software. Drive locking seems to be impossible (daunting, risky, tried and tired). It will also be good if the same software can lock files, images, video clips, movies and music files, and so on. Anything you guys used, you guys are happy with that I could use too? 103.230.105.26 (talk) 18:46, 10 January 2017 (UTC)

Here is a list of best encryption software [2]. If you happen to use OS X, there is built-in encryption capability [3]. SemanticMantis (talk) 20:20, 10 January 2017 (UTC)

Microsoft Office also has a built-in option to password-protect files. - CHAMPION ^{(talk) (contributions) (logs)} 03:42, 11 January 2017 (UTC)

Also, you can password-protect a zip file. - CHAMPION ^{(talk) (contributions) (logs)} 03:52, 11 January 2017 (UTC)

You should take care if using zip. The initial standard encryption is broken and has been for a long time, see Zip (file format)#Encryption. Probably most recent tools will either simply not support this for writing or warn you but it's possible some don't. Newer better methods are supported although as our article mentions it can be a bit messy what tool does what. 7-zip mention in the above link at least (AFAIK) is fairly standard in encryption. You also need to consider if the encryption is able to encrypt the headers including filenames and checksums (well hopefully checksums, since if the format uses hashes people don't have to decrypt your archive to work out what's stored if it's standard and not encrypted).

However the biggest concern with encryption archives but also to some extent, directory or partition like software is you need to take far greater care in not screwing up. It's a pointless for example to encrypt an archive of the sensitive stuff if you earlier stored it unencrypted on the same disk and didn't wipe that after making the encrypted file. Or if you later decrypt the content, perhaps to view it and store this on the same disk. This is less likely with directory or partition like encryption systems since they generally allow the files to be used by the OS without needing to decrypt them separately and likewise to be stored directly encrypted.

I'm assuming content being recovered from the drive/s of the computer isn't a concern this this has never been mentioned before, only from the removable drive but even so there are still risks, which is why whole disk encryption is far better especially if you don't know what you're doing and don't understand the tool. In most cases of course you do have to worry about content being recovered from the disks of the computer since if the removable drive can be stolen so can the computer. Especially if it's a laptop. And in that case you need to encrypt not just the removable drive but the drives of the computer. And even then you should be aware of the limitations, e.g. if someone steals the computer when the decryption key is in memory because it's on and unlocked. Malware. Etc.

Nil Einne (talk) 11:39, 11 January 2017 (UTC)