Computing desk
< November 12	<< Oct \| November \| Dec >>	November 14 >

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

November 13

FTP running on CentOs, allow upload but disallow delete

Hi All,

I was wondering what I could do to allow specific (non-anonymous) users to upload files but not delete them.

TIA PrinzPH (talk) 00:48, 13 November 2010 (UTC)[reply]

Program memory size

if i have written a code to load a given program on to the specified size of memory. but the specified size of memory not available in a single stretch to load the program. this problem has to be solved. to solve this problem what input and output will i have to get. 117.204.3.99 (talk) 01:33, 13 November 2010 (UTC)[reply]

It appears that you are learning about fragmentation. Have you read this article and do you understand the concept? -- kainaw ™ 15:39, 13 November 2010 (UTC)[reply]

Illustrator's equivalent of Photoshop's Twirl Filter

In Adobe Photoshop, there is a filter called Twirl where I can adjust by how many degrees I want to twist a an image. I was wondering if there was something close to this effect in Adobe Illustrator CS5 because its Twist effect does kind of the same thing but it comes out jagged and I want a smooth twirl effect for image. The image kind I want to work with is vector so I can't use the filter in Photoshop. --Melab±1 ☎ 02:32, 13 November 2010 (UTC)[reply]

"Himem.sys", a 'software driver' for use in personal computers.

This is a request for help. The subject of memory management using such drivers as Himem.sys is covered well by other pages accessable by the search engine of Wikipedia. However, some versions of Hymem.sys allow the use of a 'switch' which obviously modifies it's operation in some way. When the command: Himem.sys is set as the first command in the Config.sys file, then at boot time for the computer the operating system is loaded into upper memory and run from there. This is a necessary prerequisite for such operating systems as Windows 95 and 98, although it is not mandatory for using the early versions of Dos. The 'switch' is: ... "/ testmem on|off" ignoring the quote marks. Thus the command is either - Hymem.sys /testmem off or Himem.sys /testmem on. What Himem.sys does is obvious, what the other does is not.

My question is this. Since nowhere in Wikipedia can I find the function of this switch defined, nor can I find it defined in any Dos book either, would someone who knows please reply and attempt to explain. I have two dos books that clearly list the switch with Himem.sys without explaination.

Thank you. —Preceding unsigned comment added by Old Radio Searcher (talk • contribs) 03:27, 13 November 2010 (UTC)[reply]

I can't seem to find any reference for himem.sys on any of microsoft's sites, which is irritating, but if I recall correctly, the /testmem switch controlls a memory test that occurs during boot-up. If you have a lot of ram, and you're certain that there's no problem with it, it's worth turning that off to shave a couple of seconds off your boot time.

That's my recollection, but I could be completely wrong, I can't find a reference to back me up on this. APL (talk) 03:45, 13 November 2010 (UTC)[reply]

Google search for "himem.sys command line switches" finds several references, including [1] [2][3]. Mitch Ames (talk) 09:52, 13 November 2010 (UTC)[reply]

Search for a file called MSDOSDRV.TXT. The file, which is included with Windows 9x, describes the functions and switches of various MS-DOS device drivers (including HIMEM.SYS) under Windows 9x. An excerpt from the file relevant to the switch in question:

    /TESTMEM:ON|OFF
       Determines whether HIMEM performs a memory test when your 
       computer starts. By default, HIMEM tests the reliability 
       of your computer's extended memory each time your computer 
       starts. This test can identify memory that is no longer 
       reliable, and unreliable memory can cause system instability 
       or loss of data. HIMEM's memory test is more thorough than
       the standard power-up memory test performed by most computers. 
       To prevent HIMEM from performing the memory test, specify 
       /TESTMEM:OFF. Disabling the memory test will shorten the 
       startup process. The default setting is /TESTMEM:ON.

118.96.167.169 (talk) 01:56, 15 November 2010 (UTC)[reply]

Saving short texts online

Is there a free service that provides me with the possibility of saving short texts online for later access? When I need to do this I use drafts in my email account, but is there another way? —Preceding unsigned comment added by Jib-boom (talk • contribs) 09:05, 13 November 2010 (UTC)[reply]

I am using google docs. -Yyy (talk) 09:25, 13 November 2010 (UTC)[reply]

Pastebin 82.44.55.25 (talk) 12:08, 13 November 2010 (UTC)[reply]

delete program from the list of programs for spec. file types (and generally: delete!!)

How do I delete a program from the list of programs to be used with certain file types? (Where is that list anyways?)

After deleting a computer program (a test version of Microsoft Office 2003), it still appears in the list of programs with which to open some file extensions (e.g., docx): When right-clicking on a docx document & then clicking on "Open with," the first list item is the deleted Office version, even before the [older] working Word version is listed. 1.) How do I delete it from that list?

When I click to open the docx document with this (deleted!) program, I get two error messages, but then the basic Word (-> Office 2003) layout opens. 2.) Why is that still on the computer at all? How can I delete it?

Thanks for answering, Thanks for answering (talk) 12:40, 13 November 2010 (UTC)[reply]

You could try Revo Uninstaller http://download.cnet.com/Revo-Uninstaller/3000-2096_4-10687648.html Before using that, see if Ccleaner can fix it. If Revo does not fix it as-is, you could get Revo running, re-instal MO2003 (with Revo monitoring what was being installed), the get Revo to uninstall MO2003. Edit: there is also ZSoft Unistaller to try. 92.15.30.196 (talk) 16:29, 13 November 2010 (UTC)[reply]

Better algorithm?

I've just been given some code written in fortran that does something like this:

IF (x > 1 .and. x < 2)
A=1
GOTO 10
IF (x > 2 .and. x < 3)
A=2
GOTO 10

..repeated many times...

Now clearly the guy who wrote didnt seem of heard of a switch statement so he could of used break rather rather GOTO. Now after profiling the code (this bit plus the rest of the code) the program does seem to spend alot of time in this function, so it does seem sensible to do some optermisation here if possible. Would switching the code to a switch statement have much of an effect? or turning into IF..ELSE IF..ELSE? The code seems to be effectively a search over 3 planes (x,y,z) so would a search algorithms (some sort of tree i think?) work better? I'm not really an expert in these things so most of what i know i've picked up in its and pieces of the web, Thanks--81.147.110.238 (talk) 12:47, 13 November 2010 (UTC)[reply]

To me that seems just like an extremely awkward way to convert a float to an integer. Mind any special cases like x = 2.0, though. A binary search would be a lot better than what you have now but by no means the proper solution when INT(x) works just as well. --85.77.180.190 (talk) 15:02, 13 November 2010 (UTC)[reply]

Throwing it all out and replacing with INT is the correct solution according to what is shown here:

A=INT(x)
GOTO 10

However, that is not identical to the code shown here. According to what you have typed, functionality is undefined for x=1 and x=2. It needs to check if x "is greater than or equal to" 1. Further, using IF-ELSE would be better than just a lot of IF statements. As such, a switch wouldn't necessarily be any better once compiled. -- kainaw ™ 15:33, 13 November 2010 (UTC)[reply]

Sorry should of been clearer, the numbers i used where just randomly picked from my head when i wrote it into wikipedia, I'll have a look at binary search though, thanks--81.147.110.238 (talk) 15:49, 14 November 2010 (UTC)[reply]

Random Numbers

I'm looking for a simple program which can generate random numbers between 1 and 100 and list the frequency which each number comes up. I searched with google and found plenty of random number gen erators, but couldn't find anything specific to this, ie the listing of frequency. The computer operating system is Windows 7. Thanks. —Preceding unsigned comment added by 82.44.55.25 (talk) 14:45, 13 November 2010 (UTC)[reply]

Use an array. The program will look like this in PHP (since it is pretty much a prototyping language):

$a = array();
for($i=1; $i<=100; $i++) $a[$i]=0; // Preset all values to zero.
for($i=0; $i<999999; $i++) // Generate 999999 random numbers.
{
  $r = rand(1,100); // Generate a random number 1 to 100
  $a[$r]++; // Increment the count for $r
}
for($i=1; $i<=100; $i++) print $i.": ".$a[$i]."\n"; // Print the frequency of each index.

It is rather simple to rewrite this in any common programming language. -- kainaw ™ 15:27, 13 November 2010 (UTC)[reply]

Note that the frequency distribution can hypothetically vary a lot depending on how good the pseudorandom algorithm is. --Mr.98 (talk) 21:29, 13 November 2010 (UTC)[reply]

C++ header file problem

hi all,

i had been writing programms in C++ that was kept in C drive of my computer (it contains files of window), later i had to re install the windows,after doing so i putthe folder ie TC in c drive again. Now whenever i am making a programm and compling it a error shows up { actually every function is flashed as undefined or nut having a prototype but i know root error}

      Unable to open include file 'IOSTREAM.H '

this error shows up with name of every header file. When i press F1(help), under Possible Causes it shows :

The named file does not exit ---i know it exist i checked it out

An #include file included itself ---- i didane understood what it means please explain.

You donot have files set in CONFIG.SYS on your root directory. --- this i suspect most

Under solutions it shows:

Verify that the named file exists -- that i checked

set FILES = 20 in CONFIG.SYS --- could you please tell me how to do this

TAnx :) very much good night --Myownid420 (talk) 17:13, 13 November 2010 (UTC)[reply]

Unable to open include file 'IOSTREAM.H' - note that C++ syntax has changed somewhat from the early days. Modern convention is that C++ standard library headers are specified without the ".h" e.g. #include <iostream> (new way) vs. #include <iostream.h> (old way) - I don't know what your compiler is expecting.
The named file does not exi[s]t - even if the file exists, the compiler may not be looking for it in the correct location. You may need to update the search paths where your compiler is looking for header files (how to do this varies based on the compiler).
An #include file included itself - Circular includes (a circular dependency) occur when you, e.g. have the line #include "example.h" in example.h itself, or in another header file which is itself included in example.h. This is the main reason for "include guards", the #ifndef/#define/#endif constructs that most C/C++ programs use in their header files.
set FILES = 20 in CONFIG.SYS - CONFIG.SYS is a DOS configuration file, usually located in the root directory of the boot drive (i.e. C:\). For recent versions of Windows, it is completely superfluous, and may not even exist. The only reason for it to exist is for legacy support of DOS applications.

My impression is that you are either using a very old version of DOS/Windows, or you are using a very old C++ compiler. Unless you absolutely need the legacy support that an old compiler provides, I would highly recommend getting a modern C++ compiler. GCC is a well-regarded, free compiler available for multiple operating systems. Cygwin and mingw are Windows versions of GCC. -- 174.21.243.119 (talk) 19:39, 13 November 2010 (UTC)[reply]

the problem is that we are being tought C++ in school, i can use new versions of compiler but that will not be the as in our school, so i may feel incompatible .i am using version 3.0 and using windows XP service pack 3. i am open to all suggestions thanx--Myownid420 (talk) 02:45, 14 November 2010 (UTC)[reply]

Version 3 of which compiler? Also, how are you running the compiler (GUI/command line/etc.)? -- 174.21.243.119 (talk) 19:35, 14 November 2010 (UTC)[reply]

It looks like the compiler is Borland Turbo C (the OP says "after doing so i putthe folder ie TC in c drive again"). I think this might be the problem. If the folder containing Turbo C was simply copied into the C drive, anything set up during a full installation won't have happened, and so things like PATH statements may be in error. My suggestion would be to reinstall Turbo C. --Phil Holmes (talk) 18:34, 15 November 2010 (UTC)[reply]

Did Google have first data-center cooling towers?

I've heard that Google's data centers were the first ones to use cooling towers. Is that right? 209.42.105.74 (talk) 18:17, 13 November 2010 (UTC)[reply]

Nope. Water-cooling has existed for a very very long time in the computer industry. Cray-2 is famous for its unique shape, designed to facilitate water-cooling. Even before this, chilled water systems have been used to cool mainframes; and water coolant was commonly used even for pre-digital electronics (like RADARs and power stations). So, if anybody wants to claim that Google was the first to use a cooling-tower, they'll have to come up with some pedantic definitions of "first", "water", "cooling", and "tower." They might be able to make a claim for "biggest" towers specifically for cooling computers, but even that is a bit hard to back up; this New York Times article Google's not-so-very-secret weapon describes their cooling towers in an Oregon data center, but it isn't clear from the article how large they are. Nonetheless, massive chilled water plants are a common part of any large building or infrastructure, especially one that uses massive quantities of industrial equipment or electronics. IBM Poughkeepsie just installed 1700 tons of water-cooling capacity. And, the City of Toronto's cooling system will blow Google's towers out of the figurative water: they use deep lake water cooling, with all of Lake Ontario as a cold reservoir, to provide 270 megawatts of thermal relief for most of their downtown. Nimur (talk) 20:25, 13 November 2010 (UTC)[reply]

To be precise, the CRAY-2 was not directly water-cooled. The processors, memory, and power supplies were immersed in Fluorinert. IIRC, the Fluorinert was also circulated at low speeds from the bottom of the chassis to the top to ensure that it flowed between the densely packed circuit boards. The Fluorinert was then pumped to chilled water heat exchangers, where the heat was ultimately removed by radiators.

To answer the OP, Google was not the first to have data centers cooled by air conditioners. These have been around for a very long time, and I would imagine that these large air conditioners would have cooling towers (according to our article on cooling towers) so the claim that Google was the first to use this equipment in a data center is unlikely. Rilak (talk) 00:19, 14 November 2010 (UTC)[reply]

ipv6 and ipv4 question

hello

i need to view ipv6 website by mein isp not work with only ipv4. how to convert ipv6 to ipv4? —Preceding unsigned comment added by 188.72.107.117 (talk) 21:51, 13 November 2010 (UTC)[reply]

Section header added for the above question. Comet Tuttle (talk) 23:58, 13 November 2010 (UTC)[reply]

As I understand it, and as I understand your question, it's probably beyond your control. Assuming your operating system and browser are IPv6 compatible (and if they're relatively recent they probably are), it's probably either your hardware or possibly your ISP that isn't compatible with IPv6. If it's your hardware you can upgrade, but if it's your ISP, then there's not much you can do other than change ISPs or access the site via one that has upgraded. Maybe the site you are trying to view has an IPv4 version though? --jjron (talk) 05:22, 14 November 2010 (UTC)[reply]

Not really true. There are various ways to get IPv6 working even if your ISP doesn't have native IPv6. 6to4, Teredo, tunnel provider. There will depend on your OS, internet config, router/firewall if any and ISP (although I don't think it's often the ISP itself will be a hinderance unless youre behind a NAT or something). In some cases they may automatically work, but not all or always (and that's of course assuming they are enabled, simply enabling IPv6 may not be enough in some cases). Nil Einne (talk) 11:09, 14 November 2010 (UTC)[reply]

MP3 Download

I was looking at this website which allows one to generate a Morse code translation and then turn that into an MP3 file on this subpage. Has anyone any idea how I might download that MP3 file from the site to my computer? — Fly by Night (talk) 23:08, 13 November 2010 (UTC)[reply]

Where is says "Click here for the mp3 file", that's the link. To download it, right click and select "Save link as..." in Firefox, "Save Target as..." in Internet Explorer, or "Save linked content as..." in Opera. Then a dialog box should appear, selected where you want to save the file, and click save. 82.44.55.25 (talk) 23:48, 13 November 2010 (UTC)[reply]