Wikipedia:Reference desk/Archives/Computing/2008 September 17

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September 17

LAN/WAN Engineer

What is the most practiical way to become schooled as a LAN/WAN engineer, while already employed F/T ? —Preceding unsigned comment added by Sandrums (talk • contribs) 03:36, 17 September 2008 (UTC)

What country do you live in? Your local college may provide evening courses to teach you the subject, otherwise, a correspondence course. — QuantumEleven 13:37, 17 September 2008 (UTC)

Huge security problem in Linux

If people believe that Linux is reliable (in terms of phishing, virus, and the like), isn't it a huge security problem?Mr.K. (talk) 08:39, 17 September 2008 (UTC)

Isn't what a huge securtiy problem? - Jimmi Hugh (talk) 09:08, 17 September 2008 (UTC)

To believe that something is completely secure. —Preceding unsigned comment added by Mr.K. (talk • contribs) 11:13, 17 September 2008 (UTC)

No one believes it to be completely secure; at least those who actually work on it don't. There is constant work upon the security in Linux, as there are in other systems. People only claim it to be somewhat superior to other systems, and you'll find that the people who work with the security are quite aware that there exists no "perfect" reliability. - Jimmi Hugh (talk) 11:45, 17 September 2008 (UTC)

An end-user who believes that her/his platform is perfectly secure is the security problem, not the platform itself. The Linux platform is generally more secure because the Linux source code is fortified and because the platform is provided with tools such as AppArmor, Clam AntiVirus, Netfilter, Open Source Tripwire, Security-Enhanced Linux, Snort (software), just to mention a few. Rilak (talk) 12:26, 17 September 2008 (UTC)

Also, Linux users who think it is completely secure are likely using a standard install which, under most flavors of Linux, includes a built-in firewall and automatic updates. That is more secure than some other OS that requires the user to somehow know to turn on the firewall and automatic updates. If he or she happened to use Fedora, it installs SELinux by default also. So, in my opinion, the "ignorant" user is more secure using Linux than Windows. Of course, it is harder to find ignorant Linux users than ignorant Windows users. -- kainaw™ 12:59, 17 September 2008 (UTC)

Except that Windows Firewall and Automatic Updates are indeed on by default, and the user is required to have less knowledge of the ins and outs of increasing privelleges of applications so there is less chance of user fault causing bad security. Either way, software inheriting privelleges is bad so none of them are very secure. - Jimmi Hugh (talk) 13:06, 17 September 2008 (UTC)

Does Linux have File Protection? Since you seem to be a complete noob when it comes to Windows, I'll tell you what it is. WFP automatically detects if system files have been tampered with and replaces them instantaneously with new ones. Also, does iptables include outbound protection? You see, Windows' newest firewall prevents viruses from phoning home. Vista also includes an anti-spyware scanner (Windows Defender) enabled by default. There's also black-hole router detection, address space layout randomization, network access protection, and so on; and so on. It seems that the Linux strategy for virus prevention is simply not supporting 99% of the programs on the net. Hey--that's not sophistication...--Tree 'uns 5 (talk) 14:44, 17 September 2008 (UTC)

Back around 1995, I was running Tripwire on Linux, with the statically-linked tripwire executable and the tripwire DB stored on a write-protected floppy disk (later CD-R). If you think change detection on critical files is some new technology, I have to wonder why you're calling other people "noob". -- Coneslayer (talk) 15:49, 17 September 2008 (UTC)

I actually don't use Linux. It's too primitive. I was talking about Windows when I used the word noob, anyway. So learn to read before you put words in my mouth. I actually could go on indefinitely by listing all of the security features Windows has that Linux does not. That was just one that you chose to discuss. Speaking of Tripwire, does it come installed by default or do you have to redesign your system to get it to work? It seems like you have to do that a lot to get things to work in Linux.--Tree 'uns 5 (talk) 16:11, 17 September 2008 (UTC)

Tree 'uns 5... To answer your myriad of questions... Yes. Most flavors of Linux (the popular ones) protect the filesystem, devices, and network access. I assume you don't care about the details. -- kainaw™ 01:43, 18 September 2008 (UTC)

@Tree: $IPT -P OUTPUT DROP Oh my, whats this? Is Netfilter now blocking outgoing connections? No it can't be! Btw, Netfilter is the firewall, iptables is the program that configures it. Rilak (talk) 07:53, 18 September 2008 (UTC)

Linux users justifiably feel themselves to be safe from viruses and malware. I've been using multiple unprotected Linux machines on open Internet connections for ALL of my work for 11 years - and I have never had a single intrusion of any kind whatever. I don't have virus checking software and I don't take any special precautions beyond what the distributions provide by default.

There are many reasons for this wonderful situation - but in practical terms, casual home users and small office setups can simply ignore malware issues when using Linux. Open any attachments you like - visit any website you like - no worries.

HOWEVER: Linux doesn't prevent "social engineering" attacks like phishing (where you're tricked to entering sensitive data into the bad guy's computer) - and it can't stop junk mail, nigerian scams, etc. If someone phones you up claiming to be from Homeland Security or from your ISP and asks for your password so they can "test the line" or something - then if you are stupid enough to tell them, you'll get just as hacked with Linux as you would with Windows...so you can't completely ignore security issues.

In large commercial sites, it is important to be on guard and to keep up to date with the latest patches, etc - because Linux ISN'T 100% secure and a determined hacker could get in if he were sufficiently motivated. However, for a home or small office user - it's unlikely that anyone would be that determined...and if they were, there is probably no way for an occasional user to protect themselves - keeping up with the latest issues is a full-time job! In large organisations, the "social engineering" attack is by far the easiest - and disgruntled IT workers are a serious risk.

SteveBaker (talk) 13:58, 17 September 2008 (UTC)

People who believe that choosing the "best" software removes absolves them of the responsibility to think while using it... will always be getting themselves into trouble. The important differences between GNU/Linux and MSWin are cultural, not technical. One culture distrusts programs without source code from unknown authors; the other eagerly runs whatever it can. So to answer the original question: yes, complacency is the biggest security problem of all. --tcsetattr (talk / contribs) 20:17, 17 September 2008 (UTC)

Excel 2007 and formatted values

I have a cell, A, that has the actual value of 4.556 but is formatted to read "£4.56".

I have a cell, B, that has the actual value of 4 and is formatted to read "4".

A * B = C which has an actual value of 18.224 but is formatted to read "£18.22".

As you can see, when formatted as a currency value, the amount in the cell is rounded up / down to a set digit for displaying. My displayed cells A and B, when calculated on face value (how they are displayed) will calculate to 4 * 4.56 = 18.24; however the actual value displayed in C is 18.22 because the calculation is being done underneath.

I want cell C to show the product of the displayed values of A and B - that is, 4 * 4.56, not 4 * 4.556 so that the sheet looks consistent. Any help? 81.187.252.174 (talk) 12:43, 17 September 2008 (UTC)

C=round(A;2)*B. Note, however, that having the sheet "look consistent" is normally not desired - I for one would prefer to maximize precision. Jørgen (talk) 12:55, 17 September 2008 (UTC)

Select the cell(s) with currency. Go to Format / Cell / Currency, and set the number of decimal places you want. --- OtherDave (talk) 14:44, 17 September 2008 (UTC)

There is a "Precision as Displayed" option in Excel 2000, under Tools > Options... > Calculation. I would assume there is a similar option in Excel 2007. -Phydaux (talk) 13:28, 22 September 2008 (UTC)

windows jingles

is there anyway to turn off those stupid jingles that windows XP plays on being turned on/off; or change their volumes? thanks —Preceding unsigned comment added by 92.16.148.143 (talk) 17:00, 17 September 2008 (UTC)

Start→Settings→Control Panel→Sounds and Audio Devices→"Sounds" tab. There, either set the "sound scheme" to "No sounds" to get rid of all sounds, or set the "Exit Windows" and "Start Windows" program events to "(None)".—Ëzhiki (Igels Hérissonovich Ïzhakoff-Amursky) • (yo?); 17:11, 17 September 2008 (UTC)

windows xp

why does windows xp have norton ? —Preceding unsigned comment added by Ourhero in doom2 (talk • contribs) 18:24, 17 September 2008 (UTC)

It doesn't. Standard Windows XP does not come with any Norton Product. However, the Windows XP that comes when you buy a PC often does, because Norton pays money to Dell, HP or whoever to include it. This is called a software bundle (or, more accurately, crapware) 195.58.125.39 (talk) 18:39, 17 September 2008 (UTC)

Using a Bluetooth headset as output for windows media player

Hi all,

another WM6-related question: I bought me some shiny BT headset and it works well, at least with phone calls. But Windows Media player and other programs still output sound through speaker/wired headset output, so I am forced to wear wired headset if I don't want to disturb a whole metro with awful metal music. How do I force that the headset (if in-range) is used as primary sound output?

Thanks,HardDisk (talk) 19:24, 17 September 2008 (UTC)

If you are using XP, then ther's a guide here. Fribbler (talk) 16:17, 18 September 2008 (UTC)

Rather meant WinMobile 6, but I found BTMusic which does the trick for it.HardDisk (talk) 07:57, 20 September 2008 (UTC)

iTunes album splitting problem

I'm having a problem where a single given album is being registered as multiple albums in iTunes. For example: track 1, track 2-10, and track 11 of Year of the Rabbit are being shown as three different (but the same) albums in cover flow view. Artist, album, track #s, etc. are all consistent, so the problem doesn't appear to be with labeling, so I can't figure out the problem.--SquareOuroboros (talk) 19:33, 17 September 2008 (UTC)

Select all the tracks, edit info for them and retype the "Album Artist" - this will sort them correctly Lewiseason (talk) 20:04, 17 September 2008 (UTC)

The album artist thing seemed to fix things. What's supposed to be the difference between the artist and album artist fields? I'm still confused on that point.--SquareOuroboros (talk) 22:23, 17 September 2008 (UTC)

Many albums don't have a single author, while most songs will be listed as the artist being "Dr. Cool-Aid", others will be "Dr. Cool-Aid feat. The Huxtable Kid" (or something, I'm making artists up). These will be interpreted as different albums, unless the Album Artist is set. 90.235.13.101 (talk) 00:56, 18 September 2008 (UTC)

maybe the sorting field wrecks you, remove it individually for each track. sorting sucks. HardDisk (talk) 20:28, 17 September 2008 (UTC)

AcroRd32Info.exe

I have major problems with Adobe's AcroRd32Info.exe application. Almost every time I try to rename, move or delete a PDF file, the application I use (most commonly Windows Explorer, but, of course, for instance any application able to show file dialogs (open/save) can also be used) stops responding, until I use the task manager to kill AcroRd32Info.exe. Is there any known solution? --Andreas Rejbrand (talk) 20:09, 17 September 2008 (UTC)

Warning, non-neutral POV ahead - Uninstall the Adobe bloatware and install Foxit Reader instead. --LarryMac | Talk 20:14, 17 September 2008 (UTC)

Ditto. Saintrain (talk) 20:31, 17 September 2008 (UTC)

Whilst I agree with the above comments, if you want/need to continue using Acrobat, I recommend you uninstall your version of Acrobat Reader, download the latest version from Adobe's website, and reinstall. It sounds like a part of Acrobat Reader (possibly the explorer plugin) has somehow gotten messed up, the best way to fix it is to reinstall Acrobat Reader. — QuantumEleven 12:48, 18 September 2008 (UTC)

Upgrading MS Office on a new PC

My current Dell PC came with MS Office xp installed, and I have the reinstallation disks. I recently ordered a new computer without Office. I will no longer use my old PC after I get the new one. What I want to do is just buy the Office 2007 Upgrade, for my new PC and use my old Office xp disks to show it that I already have a liscenced copy. Will I be able to do this? ike9898 (talk) 20:51, 17 September 2008 (UTC)

Quoting to Microsoft.com^here, it seems you will have little advantage in upgrading vs buying anew if you plan to spend USD 240 or less. Might I suggest using OpenOffice.org or at least giving it a try?

Oops, forgot to sign. Kushal (talk) 01:47, 18 September 2008 (UTC)

I need Office 2007 Professional; according to your link the upgrade is $160 less than the full version. Anyone know the answer to my original question? ike9898 (talk) 10:41, 18 September 2008 (UTC)

Are zipfile passwords effective anymore?

I keep some personal private information encrypted in zipfiles with a password. But since there is software available to "crack" zipfile passwords, can I be confident that my password-protected zipfiles are secure, or could a curious teenager open them after a few minutes or longer? In other words, are password protected zipfiles sufficiently difficult to open that a teenager is unlikely to succeed, or is the security just illusionary? Thanks 78.149.194.247 (talk) 23:42, 17 September 2008 (UTC)

From what I can tell it depends on what software you've used to encrypt it with. If you use newer versions of WinZip with an Advanced Encryption Standard encryption then they should not be vulnerable to any sort of simple attack. The original encryption algorithm of PKZIP, etc., was very poor and is very vulnerable. So if you are worried about it, I'd get a new version of WinZip and re-encrypt the files with AES. Keep in mind that short and simple passwords are very vulnerable to simple brute-force methods, whereas odd passwords (e.g. mixing of alpha-numeric characters) or pass phrases are much less vulnerable. --98.217.8.46 (talk) 00:34, 18 September 2008 (UTC)

You can also use other programs to do encryption on any file. If you package a zip-file in a TrueCrypt container, you wont have to worry a lick about WinZips dodgy encryption-scheme 90.235.13.101 (talk) 00:58, 18 September 2008 (UTC)

Honestly, TrueCrypt is probably your best bet. Just be sure you don't couple that with a weak key, or someone will be able to get through it by guessing (ie. a dictionary attack). A sufficiently strong key with TrueCrypt is not feasibly breakable. For that matter, WinZip's new encyrption should be secure as well, if it actually implements AES properly. I'd still go for TrueCrypt though, as it's free, open-source, and works on OSX and Linux as well as Windows. Plus it has far more nifty options, like hidden volumes and full drive encryption and stuff. 24.76.161.28 (talk) 05:30, 18 September 2008 (UTC)

I think you mean a weak passphrase; weak key has a different meaning. As far as I know the AES encryption in WinZip (which is publicly documented) is fine. I don't know how widely it's supported, and it only encrypts the file contents, not the file name, if you care about that. TrueCrypt is fine too, of course. You can also get a TrueCrypt-like effect by putting your file(s) in an ordinary zip archive and then putting that archive in a second, encrypted archive. Whatever's most convenient. -- BenRG (talk) 11:42, 18 September 2008 (UTC)

Multiple classes

In what programming languages, if any, can an object belong to two classes at once when these classes do not share a subclass? NeonMerlin 23:44, 17 September 2008 (UTC)

See type polymorphism. In languages such as PHP, an instance may be referred to as one type of object, then another unrelated one. This is because memory is reserved as necessary during runtime, not calculated during compile. So, the instance is very flexible and can be morphed into many different classes as necessary (and cause terrible runtime problems unexpected by the programmer). -- kainaw™ 00:01, 18 September 2008 (UTC)

Hey Kainaw, can you give an example of this please? —Preceding unsigned comment added by 194.223.156.1 (talk) 12:58, 18 September 2008 (UTC)

Examples depend on what you want to do. For example, what if I have a variable $foo of some class. I want to use it as a different class, but it is missing the $bar class variable. I can set $foo->bar='something' and suddenly use it as the new class. However, the methods don't change. What if I want to change the methods? There are multiple ways to do that, such as cloning between classes or going serial as one class and back to an object as the new class. PHP is not duck typed, but is somewhere between static typing and duck typing. Also, when discussing classes, you have be very clear which version of PHP you are talking about as the class handling functions have changed a lot from PHP 3 to PHP 5. -- kainaw™ 00:44, 22 September 2008 (UTC)

Also, multiple inheritance? --71.147.13.131 (talk) 06:38, 18 September 2008 (UTC)

Also multiple interface inheritance leads to objects being of multiple types. Equendil Talk 08:17, 18 September 2008 (UTC)

As a general rule, any language that implements duck typing fits your criteria, because "class hierarchy" isn't well-defined in such a language. --Carnildo (talk) 19:01, 18 September 2008 (UTC)