Wikipedia:Reference desk/Archives/Computing/2012 February 10

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February 10

USB 3 external hard drive

I see external hard drives (HD) that use USB 3.0. My computer has USB 2.0. As I understand it, USB 2.0 speed is slower than the transfer rate of a HD but USB 3.0 is faster (than the HD transfer rate). If I put a USB 3.0 card in my computer, a USB 3.0 external HD would be faster than a USB 2.0 one, right? Would the transfer speed of an external USB 3.0 HD be close to that of an internal HD? Bubba73 ^{You talkin' to me?} 00:28, 10 February 2012 (UTC)

See List of device bit rates#Peripheral. Answer is basically yes. Moondyne (talk) 04:22, 10 February 2012 (UTC)

Resolved

Thank you. Bubba73 ^{You talkin' to me?} 05:09, 10 February 2012 (UTC)

Computers showing incorrect bit rate of songs question

I recently downloaded a song that was around 3 minutes long and was over 8 MB, which for that length in that size would be at 320 kbps, but when I right clicked the audio file, then clicked the properties options, and then clicked the details tab; I saw that it said that it was 192 kbps, which I know is incorrect. It should say 320 kbps based on the size and length. Also, I noticed there have been many past circumstances where I would download a song that was not 320 kbps, 256 kbps, 192 kbps, 160 kbps, nor 128 kbps, but a kbps between those numbers like 260 kbps or 172 kbps for example. However, when I looked at the Details section of Properties, the computer would register it at 320 kbps instead. So, why would the computer sometimes display the wrong bit-rate of songs? Is it the computer or does the error have to do with the way an audio file was compressed or made? What causes these errors? Willminator (talk) 01:29, 10 February 2012 (UTC)

Many audio files use a variable bit rate. It sounds like you are asking for an average bit-rate, which seems like the most intuitive measure of a VBR file; and your program is displaying "something else" (perhaps, bitrate of the first compressed frame, or bitrate identified in the ID3 tag, which might be incorrect). Nimur (talk) 03:14, 10 February 2012 (UTC)

Slow computer

Over the last week, my computer has been very slow. This suggests to me that perhaps something is running in the background. How do I determine if something is doing so and how do I get rid of things I don't want to be there? I haven't downloaded anything other than my emails 72.136.132.216 (talk) 02:17, 10 February 2012 (UTC)

Sorry, I forgot to add that I am running XP. 72.136.132.216 (talk) 02:21, 10 February 2012 (UTC)

I think this works on XP: do ctrl-alt-del and start the Task Manager. Click on the Processes tab. Then the CPU column will show you what percentage of the CPU each process is using. You can click on the CPU heading to have it sort them by CPU usage. Bubba73 ^{You talkin' to me?} 03:02, 10 February 2012 (UTC)

Almost. The "CPU" tab has some weird two digit numbers, most of which are 00. There's a "CPU Time" column which does what you said. You need to click on it twice to sort in descending order. Of course, CPU time might not be the limiting resources, so the "Mem Usage" column and others should be checked out, too.

Then, if you find some process you can't identify taking up an inordinate portion of the resources, kill it and see if things improve or if it manages to restart. If, on the other hand, some process you actually need (like your browser) is the culprit, then you might need to reinstall that app to get rid of whatever has infected it. You could try running some anti-malware progs first, like AdAware and Spybot Search & Destroy. StuRat (talk) 04:41, 10 February 2012 (UTC)

Those two-digit numbers in the CPU column are the percentage of the CPU that the process is using. The "CPU time" column is the CPU time it has used since it has started. I'd look first for something using a high percentage of the CPU (unless something is accessing the HD a lot). Bubba73 ^{You talkin' to me?} 05:12, 10 February 2012 (UTC)

Thanks everyone. I will go through these steps. I frequently run spybot and will do it again before I try these steps.

72.136.132.216 (talk) 17:20, 10 February 2012 (UTC)

Xbox 360s Hdd

Hi, I have an Xbox 360s with a small hdd, I want to buy a new one that has more storage, but I noticed that all the drives are internal. So, I had two questions: is it hard to install the drive? And can I keep the original drive and run it alongside the new one, or will I need to somehow remove the old drive, install the new one, and transfer everything to it? Thank you for any help:-) — Preceding unsigned comment added by 209.252.235.206 (talk) 05:50, 10 February 2012 (UTC)

See our article section Xbox 360 accessories#Detachable hard drives. The drive is a 2.5" notebook drive that's encased in a proprietary case and has proprietary firmware. Here is Microsoft's article on how to use a proprietary transfer cable to copy the contents of the old hard disk from the new one — though I think this article is about the old-style Xbox hard disks, not the "S" disks. Comet Tuttle (talk) 00:57, 12 February 2012 (UTC)

No need for extremely complicated passwords

The advent of brute force and dictionary-based password cracking has compromised many computer systems, e-mail accounts, etc. thanks to the raw computing power of advanced password crackers. The usual response has been to ask people to make up ever longer and more complicated passwords, which in turn may be forgotten by the users.

However, I've thought of a far simpler way, which would both help users stay with relatively simple passwords and solve the brute force cracking problem virtually forever: why not design all computers and encryption systems such that, if you type the wrong password, you have to wait for five seconds before you can type the password again? It would only be a very minor inconvenience for human users, but it would immediately render useless the raw computing power of advanced password crackers, regardless of how performing they may become in the future - who cares if your password cracker can calculate one billion passwords per second if it can only enter one password every five seconds? Even dictionary-based attacks with a relatively small search space would take decades or even centuries to carry out.

So... Is there a technical reason why this has not been done everywhere, or has nobody ever thought of it before? Leptictidium (mt) 10:35, 10 February 2012 (UTC)

It's a technique already widely used; as is allowing only a certain number of incorrect guesses before locking the user account and requiring an admin reset. --Tagishsimon (talk) 10:41, 10 February 2012 (UTC)

Well yes... Maybe I worded my question poorly. My question is "Why is this not done everywhere"? Leptictidium (mt) 10:42, 10 February 2012 (UTC)

That's how it works already. Massive dictionary cracking is mostly done when someone has stolen a copy of a password database and is cracking it on their own computer. -- Finlay McWalterჷTalk 10:42, 10 February 2012 (UTC)

(EC with below) Also the OP doesn't appear to understand how password cracking works. You can't design a local encryption system such that if you type the wrong password you have to wait 5 seconds. If you enforce a software limitation, this is fairly pointless since anyone who wants to crack the password will just break the software to remove the limitation. Actually few would brute force by trying to use the program anyway, this imposes unnecessary interface limitations.

What you can do is make the computation expensive and this is sometimes done. However this is not going to guarantee it will take 5 seconds per password. Someone trying to break the password is likely to have access to far more computing resources, so will be able to do far more then one per 5 second. (You'd generally not want it being much more then 5-10 seconds even if the person has some junky slow old single core.) Worse they may be able to use the GPU or dedicated hardware to vastly speed up computation (possibly in the order of 200x of more) if they're really interested.

And while this works for local passwords, it doesn't work for remote ones (where the server serves many users) since if the computation is very expensive this means it will be very difficult for the company to serve many users without spending a large amount of resources. As FM said, most companies will impose limitations on the frequency or number of tries per account which since it's remote. you can't avoid. But this doesn't help you if the database is stolen. When people do bruteforce passwords on remote computers, they usually rely on parellisation of accounts. (Actually most do this all the time.)

Nil Einne (talk) 13:25, 10 February 2012 (UTC)

Something to be aware of when enforcing a waiting period is that it can be used for denial of service. And the concept is not applicable to encryption, where the premise is that about everybody could have access to the encrypted data and you would remain safe. If it takes only 5 seconds per password to check if it was used for encryption then it takes less than 60 computers to check for the million most common passwords in 24 hours. --145.94.77.43 (talk) 13:11, 10 February 2012 (UTC)

How to create a range of passwords that don't get confused or forgotten

Hi. The above question made me think of this one. Like most people, I use a range of different passwords for different machines, websites, software etc. The ones I use often, I tend to remember, but the others get confused or forgotten.

Worse, some of the passwords I need to use have to be changed regularly, and the system won't allow old passwords to be used.

I don't want to do anything unsafe, like write them down or use just one for the lot of them.

I guess this is a common problem for techies (not me, you! This is the reason for posting here, rather than at the Misc board) so, I'm wondering if you know of any tips out there for creating suites of easy to remember safe passwords. --Dweller (talk) 10:57, 10 February 2012 (UTC)

I use Keepass to generate and store insanely un-memorable passwords. -- Finlay McWalterჷTalk 10:59, 10 February 2012 (UTC)

Sophos suggest generating a nonsense word that you can easily re-generate from scratch each time you need it. See here. On the other hand, xkcd suggests using dictionary words in unusual combinations, like this. - Cucumber Mike (talk) 13:05, 10 February 2012 (UTC)

So now you know, when hacking into a geek's computer, forget trying pet names, go straight for correcthoresebatterystaple. Works every time. - Cucumber Mike (talk) 13:18, 10 February 2012 (UTC)

If it's just for web sites, Firefox's built-in password autofill feature works pretty well. Otherwise, there are various password manager programs you can use. Generating passwords can be done with a "key derivation" function like PBKDF2. You'd choose a "master password" from which the others are generated, and use the name of the web site you want to log into as the salt. 67.117.145.9 (talk) 00:11, 11 February 2012 (UTC)

Hello again. I often use computers that I cannot add software to. Not only that, but the passwords I need to use are often ones that give access to the computer itself, as well as websites etc. So for these reasons, your suggestions don't really help. Are there any good mnemonic devices you've come across that help generate multiple memorable but safe passwords that don't get confused? --Dweller (talk) 16:53, 14 February 2012 (UTC)

How can I tell if I have USB 3.0?

How can I tell if my computer has USB 3.0? I think it is only USB 2.0, ut I want to check. I tried control panel/system, Speccy, and Belarc Advisor, but none of them seem to say. Bubba73 ^{You talkin' to me?} 17:14, 10 February 2012 (UTC)

Open Device Manager (Start -> Control Panel -> Performance and Maintenance -> System -> Hardware -> Device Manager). Look for the entry for Universal Service Bus Controller and expand it. If you see 3.0 mentioned, you're all good. If not, look for 'Super Speed', which indicates USB3.0. 'High Speed' or 'Enhanced' denotes USB2.0. If you don't see any of these, you can right click on each entry, choose Properties and then click the Advanced tab. Again, you're looking for 'Super Speed' for USB3.0, or 'High Speed' for USB2.0, like in this picture. Bon chance! - Cucumber Mike (talk) 17:38, 10 February 2012 (UTC)

An alternative is to figure out which USB controller is installed and look up its capabilities. For example, Device Manager (on Windows 7) reports my machine has an Intel 631xESB/632xESB I/O Controller Hub. Reading the datasheet for that one sees that it supports eight USB2.0 ports (but no USB3). Doing the same for any machine should be similarly straightforward. -- Finlay McWalterჷTalk 17:42, 10 February 2012 (UTC)

Resolved

Thanks, I don't see anything that says 3.0 or Superspeed. I do see "hub is operating at high speed", so it must be 2.0. Bubba73 ^{You talkin' to me?} 23:30, 10 February 2012 (UTC)

TV brightness

I have a perpetual problem with night scenes viewed on Netflix streaming being too dark to see on my CRT TV. No doubt most of the problem is at their end (either when a digital recording is first made or when converted to streaming digital), but I'd like to also be able to fix it at my end. This is what I've done so far:

1) Turned off all the lights and installed black-out drapes to darken the room.

2) Turned the brightness and contrast to max on the TV.

While these help, it's still impossible to see anything at times. I'd also consider getting a new TV. However, the "brightness" rating they give seems to be how bright it is when displaying a white scene. What I need to know is how bright it can be made when displaying a dark scene.

A) How can I get this info before making a purchase decision ? The only way I can think of is to hang out in showrooms and wait for very dark scenes to appear, then trying to compare models. Of course, this would only allow me to compare them at their current settings, as I'm not likely to be able to turn the brightness and contrast to max in the showroom.

B) Also, would a computer monitor used as a TV generally be better, worse, or the same as a regular TV, in this respect ?

C) How would the format, such as CRT, LCD, DLP or plasma compare ?

D) Would a dynamic contrast ratio help (where the back-light level is adjusted depending on the scene) ?

E) Any other suggestions ?

StuRat (talk) 19:42, 10 February 2012 (UTC)

Regarding A, TVs in the showroom will invariably be already set to max brightness/contrast, in order to make them seem as vibrant and eye-catching in a brightly lit store. This setting is typically inappropriate in an actual home viewing setup, and having the contrast too high may be a major part of the problem you are suffering.

D may help, but I would have thought it unnecessary in a darkened room.

To get everything set up well at your end I would recommend using a calibration disc. Many DVD and blu-ray movies will actually have this function, so it may not even require a special disc if you already have such a film in your collection - for example this page discusses the item on THX labelled DVDs. You could also check the manual for your TV set, as some models are capable of displaying built-in test patterns. AJCham 00:38, 11 February 2012 (UTC)

Thanks so far. Any other suggestions ? StuRat (talk) 02:54, 13 February 2012 (UTC)

no isp

1) if you dont have an isp, is there a way to hook a pc to a phone jack and use the internet? thanks, jake (p.s. i forgot my password, to here and my email. must. kill.) 70.114.254.43 (talk) 23:55, 10 February 2012 (UTC)

2) also, two more quastions. can you write a program that starts itself?

3) and, how do i block sites with the hosts file on windows 7? thanks again, jake 70.114.254.43 (talk) 00:02, 11 February 2012 (UTC)

I numbered your questions for you:

1) Not really, although some ISP progs will let you use them for free for a bit to test them out.

2) No, but you can have a program that's started at boot-time by the O/S, then stays dormant until it decides it's time to do something. StuRat (talk) 00:12, 11 February 2012 (UTC)

thanks sturat. 70.114.254.43 (talk) 03:49, 11 February 2012 (UTC)

For a couple of decades at the end of the second millennium, when they had phone lines but didn't have normal Internet yet, you could connect a computer to a PHONE line (a physical phone line), have it make a call (make phone tones, as if it was placing a call), another computer would answer, and then they would "talk" (over the phone line) and you would get Internet at like 0.05 megabits. It cost almost as much as a phone line itself costs (you paid to the company owning the computer that "picks up"), but of course you also had to pay your own phone company (what today would be an ISP) so you would have your own phone line and any charges you accrued at the same rate as a real voice call on that line (so some people paid by the minute, some people got a free local number service from their phone company, didn't have to pay extra locally on their land line phone). I don't know how the companies that picked up the phone when your computer called got on the Internet though, as it seems this just wouldn't scale. There had to be something else, as obviously they didn't have a phone line between your Internet company and every web site you access, so I dunno. --80.99.254.208 (talk) 09:36, 11 February 2012 (UTC)

As an interesting point, I heard that AIM started out as this kind of service too. I forgot to answer your original question, but I heard that some people were still paying AIM even though there's already home Internet, (which is a joke), but you should look it up. It should be possible to pay for AIM, and then dial in on a LANDLINE from your computer and have it talk to aim and get the Internet. It probably works on a cell phone too, but unless you have unlimited minutes you better watch out. Maybe AIM has made this a free service by now, I don't know. The point is, it should be possible to get on the Internet using nothing but a phone if you don't have an ISP. --80.99.254.208 (talk) 09:40, 11 February 2012 (UTC)

Are you talking about a dial up ISP? Or just basic modem communication? The early days of ISPs were bulletin board systems (BBSs), the more progressive of which would have an internet link. But, while this is kind of tautological, if you're connected to the internet, however you're connected is your ISP. So no, you can't get on the internet if you don't have an ISP. Shadowjams (talk) 23:29, 11 February 2012 (UTC)

Another point... I'm going to start feeling old here, but by AIM I assume you mean AOL, which was a large intricate online community (like a BBS) that began to add internet connectivity. By the time of the AOL Instant Messenger I think they offered internet access to all their customers. AOL did indeed have dial-up computers, and I suspect most people here over 25 remember the familiar modem tones when they connected with their modem. Shadowjams (talk) 23:32, 11 February 2012 (UTC)

WRT the hosts file, the path is c:\windows\system32\drivers\etc. The HOSTS file has no extension; there may also be a example version hosts.txt - make sure you don't edit the wrong one. You can edit it using notepad, but will need to do so using an Administrator account. The HOSTS file contains examples, but you can add something like:

127.0.0.1 www.site-to-block.com

which will redirect attempts to visit www.site-to-block.com to the localhost. --Kateshortforbob _talk 11:29, 11 February 2012 (UTC)

How does ISP Work? How they connect all computers of the world with mine? 190.60.93.218 (talk) 12:30, 15 February 2012 (UTC)