Seagate External Hard Drive Fix
Formatting Disk
Two levels of formatting
Formatting a disk for use by an operating system and its applications and files are two very different types of formatting. First, a low level (closer to hardware) in the form of program will mark the surface of the disc of industry figures and other information to be used later in normal operation by the disk controller. This is intended to be the of the permanent record, and is often completed at the factory.
High-level formatting occurs during installation of the operating system, or When you add a new disk. This included the format of the file system. disk system and distributed file will specify a boot block optional, and the volume of diverse information and directory for the operating system.
The low-level formatted floppy
Formatting Low disks (and early hard disks) is performed by rolling the HDD.
The process is easier described with a standard 1.44 Mo mind. The low-level format the floppy normally writes 18 sectors of 512 bytes each on each of 160 tracks (80 on each side) of the disk, provide 1,474,560 bytes of storage on disk.
The sectors are physically larger than 512 bytes, because they contain numbers sector, CRC bytes, and fields of synchronization, indicating the correct speed at which read data off the disk. These extra bytes are not normally included in the figure cited for the overall storage capacity of disk.
Different sizes of low level can be used on the same medium, for example, important documents can be used to reduce the size of inter-record gaps.
Several freeware, shareware and freeware (eg GParted, fdformat, NFORMAT and 2M) has much more control over formatting, allowing the shaping of high-density 3.5 "disks with a capacity of up to 2 MB.
Techniques used are:
head / track sector angle (forward movement of the sector numbering change and follow step by step to reduce side mechanical delays)
interleaving sectors (sector gap and thereby minimize the number of sectors per track to be increased)
increasing the number of sectors per track (while a normal 1.44 MB format uses 18 sectors per track, it is possible to increase this figure to a maximum 21), and
increase the number of tracks (most readers could not tolerate the extension to 82 tracks, although some could handle more, others could jam).
Linux supports a variety of sizes area, and DOS and Windows to support a large-sized record-DMF format a disk. [Citation necessary]
Low-level formatting (LLF) of hard disks
Low-level formatting of a disk of 10MB IBM PC XT hard.
User instigation formatting Low (LLF) disk drives were common in 1980. Usually this parameter causes MFM disk, so that sectors of bytes can be successfully written to. With the advent of RLL encoding, low-level format grew increasingly rare, and most hard Modern drives are embedded systems, which are low-level formatting at the factory with the dimensions of the physical geometry, and therefore not subject to intervention user.
Early hard disks were quite similar to floppies, but low-level formatting is usually done by the BIOS rather than by the operating system. This process has involved the use of debugging program MS-DOS to transfer control to a routine hidden at different addresses in different BIOS [Citation needed].
In the early hard drives were often imprecise mechanisms head-motion based on the technology of stepper motors which finds tracks by advancing step by step a number of steps. Ideally the right track then appear under the head. But a disc formatted horizontally often could not operate in a vertical orientation, because of force of gravity pulling on the mechanism and moving the head slightly out of alignment with tracks written in the horizontal position. It is usually necessary to LLF a drive for the orientation, it was designed to be used.
Early hard drives also tend using a magnetic storage material with low resistance to demagnetization (coercive field). A MFM / RLL disk containing data that was rarely written would eventually develop errors in the data itself due to opposite magnetic fields that define data bit of softening and neutralize each other. Although the data would become unreadable, it was not due to faulty media. The process of low-level format can erase these sectors soft and firm up new frontiers in the mud, allowing the reader to run again as if it were brand new for a little longer. Some older disk utilities such as Spinrite's sector included a refreshing who read and rewrite all sectors to strengthen the sector magnetic fields.
Transition away from LLF
From the early 1990s, the formatting low-level hard drives become more complex as technology improved with:
the move from FM to MFM to RLL encoding,
introduction a little box, which stores more sectors on outer tracks compared to the more intimate short runways. This improves storage density and allows faster transfer rate on the outermost tracks.
the transition from track numbers encoded on a separate tray for the servo, to encode track numbers in the same area of the disk data, simplifying the hardware and
increase the mechanical speed of the order.
Rather than face growing problems with BIOS versions, the disk vendors started doing low-level formatting at the factory. Today, an end user, in most cases, should never perform a low-level formatting an IDE or ATA hard drive, and in fact, it is often not possible to do so on modern hard disks outside the factory.
The main reason for low-level format can not be done because readers Modern engines do not step to find the tracks, and there is no way to determine where the tracks should be recreated media. Instead of modern drives the heads are positioned using a servo analog continuous, often called the voice coil because it works almost exactly like an audio speaker analog.
Modern readers find tracks based on special data control servo permanently written to the disk platters at the factory by the manufacturer of the hard disk, using highly specialized equipment. Early servo-controlled using a separate tray entire disk to store the data read-only servo, but it was ineffective. store modern readers servo data embedded directly among the regular tracks and sectors, and operate in a way that data is absolutely servo never crashed for any reason. Data Loss servo leads to loss of the ability to locate the data tracks.
Servo data is why modern readers can operate in any position relative to the beginning of MFM and RLL drives. The positioning of the head is based on data integrated directly into the media itself if the reader always knows exactly where the heads should be placed, and the servo can immediately compensate for any movement that would otherwise misalign shock MFM drives and get the step by step in line with the tracks, which requires a search to track zero resynchronize step.
reset disk
This section needs additional citations for verification.
Please help to improve this article by adding reliable references. Unsourced material may be challenged and removed. (July 2009)
While it is impossible Making LLF on most modern hard drives (since the mid-1990s) outside the factory, the term "formatting low level "is always used (wrongly) for what should be called Resetting a hard disk to its factory configuration (and Even these terms may be misunderstood). Reset should include identifying (and sparing, if possible) the areas that can not be written and read on the reader, and rightly so. The term has however been used by some to refer to only part of this process, in which all sectors of the disk that is written, usually by writing a zero byte to every addressable location on the disk, sometimes called zero filling.
Ambiguity present in the term "low-level format" seems to be due to both inconsistent documentation on websites and the belief by many users all processes under a "high-level (file system) format" should be called a low-level format. Instead of correcting this idea erroneous (clearly indicating such a process can be performed on specific drives), drive manufacturers have actually described various software reset as LLF utilities on their websites. Since users generally have no way of determining the difference between a true LLF and reset (they simply observe the results of running software in a disk drive must be partitioned and "formatting High-level "), both the user misinformed and mixed signals from various drive manufacturers have perpetuated this error. Note: Whatever the possible misuse of these terms may exist (search websites of manufacturers of hard disk for all these terms), many sites are services publicly available reset (perhaps a floppy disk or CD image files), both to replace each byte and check for bad sectors on the hard disk.
A popular method for the scene that the "zero fill" the operation of a hard disk is write a zero byte on the disk using the dd utility of Unix (Linux also available) with the "/ dev / zero" listen to the source file (if =) And the drive itself (or the entire disk or partition specific) output file (of =).
High-level formatting
Formatting top level is the process of setting up an empty file system on the disk and install a boot sector. This takes little time alone and is sometimes regarded as a format "fast".
In addition, the entire disk can be scanned for possible defects, which takes much longer, up to several hours on large hard drives.
In the case of disks, two top and low-level formatting is usually performed in a single pass by the software. In recent years, most floppies have shipped preformatted at the factory as DOS FAT12 floppies. It is possible to format them again to other formats, if necessary.
Reformatting
A high-level format procedure is sometimes done a disk operation to clear the hard drive. What is commonly called a reformatting. Although it can not completely erase all data disc (see below), it deletes critical areas, such as the boot sector and partition table. This gives the appearance of a disc vacuum in the operating system, making all existing content available through normal methods.
Reformatting is often the implication that the system operating and all other software will be reinstalled after formatting is complete. Rather than fix a system suffering from malfunctioning or compromising safety, it is sometimes considered easier to erase everything and start from scratch. There are several familiar process, such as "wipe and "Reload" nuke and pave "," re-image ", etc.
Formatting DOS, OS / 2 and Windows
Under MS-DOS, PC-DOS, OS / 2 and Microsoft Windows, disk formatting can be done by the format command. The program format usually requires confirmation prior to prevent accidental deletion of data, but some versions of DOS have an option AUTOTEST undocumented / and if it is used, confirmation is usually ignored and format begins immediately. The WM / FormatC macro virus uses this command to format drive C: when a document is opened.
There is also undocumented parameter / U makes a unconditional format which overwrites the entire partition, preventing the recovery of data through software (but see below).
Retrieving data from a formatted disk
As with the regular deletion, data on a disc is not completely destroyed in a high-level format. Instead, the area on the disk containing the data is simply marked as available (regardless of the structure of file system uses the format), and retains the old data until it is replaced. If the formatting is done with a different file system than previously existed in the partition, some data can be replaced if that is not the same system files were used. However, in some file systems (eg, NTFS, not FAT), the index file (Such as $ MFTS under NTFS, "inodes" in ext2 / 3, etc.) can not be written in the same exact spot. And if the partition size is increased, even the FAT file systems overwrite more data at the beginning of this new partition.
From the standpoint of preventing the resumption of sensitive data with tools of recovery, data must either be completely overwritten (every sector) with random data before format, format or program itself must perform rewrite this as the DOS FORMAT done with diskettes, filling every sector with the data byte value in hexadecimal F6.
See also
deleting data
data remanence
Data Recovery
Drive mapping
References
^ NOSPIN Group, Inc. (e). Low level formatting an IDE hard disk. Accessed December 24, 2003.
^ The PC Guide. Site version: 2.2.0 Version Date -: April 17, 2001 Low-Level Format, Zero-Fill and Diagnostic Utilities. Preview September 24, 2007.
^ Trail of data by the disc method Patentstorm Seagate Research patent 5777816, the use of a dedicated servo surface.
^ "AXCEL216 / MDGx MS-DOS Undocumented + Hidden Secrets". http://www.mdgx.com/secrets.htm # FORMAT-U. Retrieved 7/6/2008.
External links
Secure Deletion of Data from Magnetic and Solid State Memory by Peter Gutmann
Differences between a quick format and a regular format during a "clean" installation of Windows XP from Microsoft Help and Support. Useful for anyone setting their own computer and need advice on the subject!
support.microsoft.com How to Use the Fdisk Tool and the Format Tool to Partition or repartition a hard disk
Help: I hacked. Now what do I do? – Microsoft Tech Net: Why should you wipe a drive compromise for metal nu. Article by Jesper M. Johansson, Ph.D., CISSP, MCSE, MCP + I
Categories: rotating disk storage media | File system management | DOS on IBM compatible PC | OS / 2 | Windows administrationHidden categories: All articles linked | stubs by February 2007 | stubs from July 2008 | Articles lacking sources from July 2009 | All articles lacking sources About the Author
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