what is demagnetization of computer hard disk?
145532
think of your harddrive like an old fashioned record.  It is basically a blank sheet until something is written to it.  A PC writes data to the disks of a hard drive by applying a magentic field to the surface of the disk and that forces the disk to orientate the surface into a certain pattern.  When the hard drive comes back around and attempts to get that data again it can detect in which order that data was written (1 or 0) and then the hard drive sends data to the rest of the pc to do whatever you want it to.\n\nDemagnetizing a drive is a way to use an extremely powerful magnet to force any data that has been written to the harddrive to "mess itself up" so that it is no longer readable.\n\nNot really practical for Joe User, but I do know that government, law offices and some medical groups will send old hard drives to companies to have them destroyed in this manner.
68649
Over time, files and applications become scattered in various places on your hard disk. Disk Defragmenter brings these scattered pieces together to improve speed and help prevent errors. \n     Steps: 1.  Close all applications. Disable screen savers, anti-virus utilities and other constantly running programs.   \n2.  Open the Start menu and choose Programs, then Accessories.   \n3.  Click on System Tools.   \n4.  Click on Disk Defragmenter.   \n5.  When the Select Drive window appears, click on Settings.   \n6.  Check both "Rearrange program files so my programs start faster" and "Check the drive for errors."   \n7.  Click OK to defragment drive C: (the physical drive).   \n8.  Run the program once a month or so.     \nTips  Run ScanDisk beforehand for best results. This is best done by restarting the computer in MS DOS and typing "scandisk" at the C:&#92;> prompt. Return to Windows afterwards to defragment your hard disk.    If you're having difficulties, press Ctrl+Alt+Delete to make sure you haven't left any applications running. Highlight each application in the screen that appears and click on "End Task" to close the application.
739404
Well using some very basic terms...basically a hard drive is made up of what they call metal platters.  Think of a dinner plate but much smaller and made of metal.  There is what is called an armature that moves back in forth over the platters and attached to the arm is a little tiny device called read/write head.  This device uses magnetic fields to change the polarity in a very small part of the metal platter.  If the charge the device creates is less then a certain amount then the computer reads it as a 0 and if the charge is greater than a certain amount the computer reads it as a 1.  This produces the binary code that computer process all commands in.\n\nThe read/write both records and retrieves the magnetic charge on the different areas of the platters and most hard drives have anywhere from 4 to 8 platters.\n\nThere is also of course a whole lot more to hard drives such as caching and learning about sectors/head/tracks and cylinders.\n\nI would recommend maybe getting a computer book from Barnes and Nobles or Borders.  Also you might want to check www.howstuffworks.com and doing a search on hard drives!
781140
Data written is not a physical substance. When you write data to your HD/Floppy, all you are doing is changing the magnetic orientation of the disk and nothing else  and when you delete the data you change the orientation again. Nothing is actually created or destroyed.
2874
In the context of administering computer systems, defragmentation (or defragging) is a process that eliminates fragmentation in file systems. It does this by physically reorganizing the contents of the disk in order to store the pieces of each file close together and in order (contiguously). It also attempts to create large regions of free space using compaction, to impede the return of fragmentation.\n\nAims of defragmentation\nReading and writing data on a heavily fragmented hard drive is slowed down as the time for the heads to move between fragments on the disk surface can be substantial. The disk operates at speeds millions of times slower than the CPU; thus the desire to process more efficiently encourages defragmentation. Operating system manufacturers often recommend periodic defragmentation in order to keep hard drive access as fast as possible.\n\nFragmented data also spreads over more disk than it needs. Thus one may defragment in order to compact data storage before splitting a single partition into two or more partitions (for example, with GNU Parted, or PartitionMagic).
162518
To answer the 1st part of this question, police will use some sort of data recovery software to gather data.  Basically what they should do is take a snapshot of the machine and then do a bit for bit data transfer from one hard drive to another, then they can play with their second drive to recover data while preserving the original for evidence.\n\nTo answer the 2nd part of the question.  In order to completely delete data off the disk it is possible and not really that difficult.  Do a web search for "how to zeroize a drive" and there is software out there that will do it for you.  The software will read the drive and mark any sectors that are not "write protected" and it will go back and write all 0's to the data storage portion of that sector.  Takes a long time depending on the size of the drive and the number or "wipes" you want to do, but after doing this, then the data is gone.
426244
if you heat them beyond 170 degrees Fahrenheit (80 degrees Celsius) the magnets will quickly loose their magnetic properties. Sustaining these temperatures for a length of time or heating the magnet significantly higher than this will permanently demagnetize it.  \nOther types of magnets such as Samarium-Cobalt have higher heat resistance.  There are also other types of Nd-Fe-B magnets that are not as susceptible to heat induced flux degradation.\n\nAs per wikipedia\nPermanent magnets can be demagnetized in the following ways:\n------------------------------------------------------------\nHeating a magnet past its Curie point will destroy the long range ordering. \nContact through stroking one magnet with another in random fashion will demagnetize the magnet being stroked, in some cases; some materials have a very high coercive field and cannot be demagnetized with other permanent magnets. \nHammering or jarring will destroy the long range ordering within the magnet. \nA magnet being placed in a solenoid which has an alternating current being passed through it will have its long range ordering disrupted, in much the same way that direct current can cause ordering. \nIn an electromagnet, ceasing the flow of current will eliminate the magnetic field. However, a slight field may remain in the core material as a result of hysteresis.
483065
I wouldn't even worry about it. The stuff on those disks is superfluous at best, borderline malwear at worst. It's all completely unnecessary, and frankly, you're better off without it on your pc, for the space it frees up if nothing else.
161461
Demagnetizers were used on cassete tape heads to keep the heads from developing "residual magnetism" and slowly erasing your recorded programs each time the tape was played.\nThey were also used on larger reel to reel tapes to blank a tape before recording, they were called bulk erasers.\nEither one will have enough intensity to work on a screwdriver.\nA magnetized screwdriver needs to be de-magnetized if you have any doubts at all.
201560
chkdsk = check Disk... it allows a personal scan of ur PC to make sure it's in its up top working order and there is no currpted files... it also allows it to fix the problem and restore it back to the normal state.  Very good to use when you are haveing hard ware issues
1129449
hdd store data in cd/dvd kind of media. not magnetic kind present in floppies.\n\nData is stored in hdd by lasers in form of pits stops etc. (Magnet proof)
84928
There is a software called Easy recovery that has tools for testing the mechanical and logical functions of any hard drive.  You need another hard drive if you are going to attemp any data recovery though.  Check the website.
1067518
if you have made partitions correctly and formatting only c drive then data from c drive only will be destroyed.it won't affect other drive data.if you are formatting whole hard disk then only total hard disk will get formatted.
610566
To format the hard drive before you dispose of it (ie get rid of all the data stored on it) get a magnet and rub it across the disk (silver part in the second image in the link below). This should erase all data on it.\n\nGOOGLE IMAGE RESULTS FOR HARD DRIVE:\nhttp://images.google.co.uk/images?svnum=10&hl=en&lr=&q=hard+drive&btnG=Search\n\nHope this Helps!
868519
By deleting files you don't need anymore, or moving files to another drive.  Without knowing what's on your D: drive, I can't really be more specific than that.
526990
It can be demagnetized by being placed into an electromagnetic field.  Old ringer phones would produce such a field when the bell rang but I don't think a cell phone will produce an electromagnetic field sufficient to demagnetize a motel room key.\n\nAn interesting side note:  If you have an eel skin billfold, it will, over time, demagnetize your credit cards, motel keys, etc.  I don't know why but it will.
238356
The Hard disk is layers of magnetic disks that has open spaces for storing file, however the files are stored permanently, unless you delete it, the hard disk also causes fragmented files that can slower down the computer, to defragment, use the disk defragmenter on your computer, and also I have a trivia for you: the read ang write head of a hard disk is 100 mm. away from the magnetic tape so don't move or bump your computer when it is on, so be careful.\n\nThe CD-ROM drive (or Compact disk-Read only Memory drive) is used to read CD-ROM, CD-R, CD-RW and other more but there is a difference, it only reads the data inside the CD, so for your safety, you cannot delete the files accidentally you know, CD-ROM drive have different speeds, highest today is 52x, but the slowest is 32x, so watch your CD's modification of how high it can take so it doesn't crack. it has also an eject and close button equipped so you cannot damage the opening sequence, also, this drives also have volume adjusters to adjust volume, and lastly, most drives today has a emergency eject button, its purpose is you can eject the disk even though the computer is off, just push a paperclib in the hole near the eject and close switch until the covers springs out and pull, and most of all, it has a headphone socket so you can listen to your audio even without speakers.\n\nMODEM is the acronym for Modulator-demodulator, it connects and disconnect line connections,it can be internal or external, external are better than internal but make sure \nyou have enough desks space and sockets!, the internal is installed to your computer in a PCI slot, it has its own power supply and makes enough space for other equipment, but you have take out the cover of the PC to take the modem to the computer shop. also you need an ISP (Internet Service Provider or Internet Package Solution) and net browser(Microsoft Like Internet Explorer, Macintosh Fire fox and Others) before you connect to the internet.\n\nSo happy day!