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Wednesday, 20 May 2015 00:00

Reading damaged files

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System requirements

Operating system – Windows 95/98/ME/NT4/2K/XP/2K3 and above.
(Detailed information about operating systems is in 'Compatibility' section.)

Agreement

Non-Stop Copy is absolutely free of charge and free to use program. You can freely share it and include into the composition of any other free distribution kits and storage media complying with the following conditions:

1) your distribution kit includes all files of original distribution;
2) all files of original distribution kit shall not be modified or altered;
3) all files of original distribution shall be installed into one catalogue.
Original distribution kit you can obtain from the developer’s official website.

Designation

The program allows copying damaged files from any type of storage media and information form unreadable sectors is zeroed. It also makes several attempts to read information from difficult to read sectors.

The program does not utilize any low-level information reading techniques and owing to this it will work correctly on any type of storage media or any file system supported by the operating system.

Using the program

To copy a file press Select File. The program will ask you to indicate the source (copied) file and name and location of target file (where to copy it). To start the copy process, press Start.

To continue copying file which has not been completely copied by another program, press Select File and indicate a source file (copied) and then indicate incompletely copied file as a target file. If you did everything correct, then the map shall indicate that a part of file has already been copied successfully. To start press Start.

You can also copy in one target file from different source files, for example, if you have several identical file copies. To do that, first launch copy of one of these files and wait until the program copies whatever it can and stop copy. Then press Select File and indicate the consecutive file copy as a source file. Launch copying. If after doing that bad sectors still remain and you have file copies, you can indicate consecutive source file again and so on.

During copy process two buttons are available: Stop and Cancel. Stop button stops the process completely and all information about the state of process at the moment of stopping is saved (see below). After it is stopped, the target file has the same size as the source file. It contains whatever was copied and those parts which were not copied or not managed to copy are zeroed. Cancel button completely cancels the copy process and whatever was copied will be deleted. In general, this button is there if you need to stop the process quickly and you are not any more interested in its result. For example, pressing Stop button at the beginning of copying a large file can lead to a certain delay due to zeroed part of the file which was not copied. Cancel button in this case will interrupt the process at once.

All data about copy process – some information about source file and map of bad sectors – are stored in NSC file. This file is stored in target file catalogue under the name derived from the name of target file adding extension .nsc. In case if copy was performed completely and there are no bad sectors left, then the NSC file is not saved or deleted if it was saved before. During the copy process NSC file is automatically saved periodically that is determined in the ‘Autosave period of NSC file’ option.

It is not advisable to delete NSC file since it can tell you whether the file in this catalog was copied incompletely. Moreover, you will always be able to continue copying from this file.

If you want to check information on any file copied with the help of Non-Stop Copy, press 'Display information' and select either copied file you want to check about or corresponding NSC file. NSC file is saved with attribute ‘hidden’, therefore, to see it you need to turn on 'Display hidden files' in explorer.

Description of the process of copying

The process of file copying is divided into 4 stages: fast copy, preview, precise preview, bad sector copy. The purpose of this division is to copy as many good sectors as possible within the shortest time period and get a detailed understanding of bad sectors.

Fast copying. A file is copied in quite large blocks. The size of block is determined by ‘Fast copy buffer’ option; if ‘Auto’ option is on, then the buffer equals to 1 MB when copying from fast storage media (CD, HDD), and 64kb when copying from slow media (FDD). If there is a bad sector inside the block, full block will be considered as bad. As a result we achieve a much faster passing of bad sector groups and get a tentative picture of file’s bad areas.

Preview. Every bad area is copied sector-by-sector until the first bad sector, moving from the start of bad area and then from the end of bad area backwards. As a result we save the time and get more precise picture of bad sector groups localization.

Precise preview. The program attempts to copy each sector in all bad areas. When this stage is completed you get a real picture of bad sectors.

Copying bad sectors. The program makes several attempts to read and copy each bad sector. The number of attempts is determined by ‘Attempts to copy bad sector’ option. This is the basis of the program’s ability to copy information from difficult to read sectors, as in some cases (for example, old or poorly recorded CD-R) there is still a chance that sectors will be read and recovered.

Such division into stages allows the user to solve the following issues during the copy process: to wait or stop on whatever you have already achieved. If you think that what you have already copied is enough, just press ‘Stop’. Later on you will be able to resume copying if you will not be satisfied by results.

The program can be set up in such a way that the last stage will repeat the file is successfully copied. That is why the program is called Non-Stop Copy. You can set such behavior with the help of ‘Max. no of ‘bad copy’ cycles’ option which determines the number of times the last stage will be repeated.

During the copy process the program tries to control time spent in this or that read operation. Gap between the time intervals is set by options available in ‘Data read time-outs’ section. Unfortunately, one cannot say whether it works or not, it varies from case to case. The program fairly ties to cancel the read operation when time lapses, and the rest depends on drivers installed in the operating system and on drive itself.

Options

‘Fast copy buffer’ determines size of block during fast copying. If ‘Auto’ option is on, this value is selected automatically depending on the type of media containing source file: 1mb when copying from fast media (CD, HDD) and 64kb when copying from slow media (FDD).

‘Attempts to copy bad sector’ determines the number of attempts to copy a bad sector at the stage ‘Bad sectors copy’.

‘Max. number of ‘bad copy’ cycles’ determines the number of times the ‘Bad sectors copy’ will be repeated subject to presence of bad sectors. If this value is 0, the number of repeated cycles is unlimited and the program will carry on trying until absolutely everything is read and copied.

Values in the section ‘Data read time outs’ determine in how many milliseconds the read operation will be canceled for each stage separately and file area which is being read is marked as bad. Don’t get carried away by lowering these values, because the program can really start marking readable file areas as bad.

‘NSC file autosave period’ determines in milliseconds how often NSC file will be automatically saved during copy process.

‘Data medium readiness check period’ determines in milliseconds, how often the program will inquire about medium readiness in case the medium is ejected during the copy process.

Section ‘File’s map colour settings’ allow the user to change the colour of corresponding element on the map.

Command line

You can work with the program via command line.

Usage:

nscopy.exe [Seource File] [Target File] [/e] [/p] [/w] [/c] [/u]
or
nscopy.exe [<File or NSC-file> /i]

where:
Source File – name of the source (copied) file
Target File – name of the target file (where to copy)
File or NSC file – name of copied file, information about which you require, or name of NSC file
/e – exit program after copying is completed
/p – turn off the computer after copying is completed
/w – do not start copying immediately
/c – show file selection dialogue
/i – show information about file copied
/u – do not display messages that require user actions

Compatibility

Full functionality is supported with Windows NT
(NT4/2K/XP/2k3/...)

The program has one restriction for Windows 9x (95/98/ME) – data read time outs don’t work. Although the loss is not huge since it rarely works.

Additional information

Read ‘howto.txt’, there you can find some useful information. For example, how to copy entire catalogues with the help of NSCopy.

Specially for ‘geniuses’ who discovered binary files editors. In case of modifying author’s rights (copyright line is at the bottom of main window), the correctness of program’s work can suffer a lot. Just a little hint.
If you really want ads, nothing prevents you from creating an installer that will advertise whatever you want.

Known problems

- TAB and ENTER doesn’t work in the main window.
- When ejecting disk during the process of copying in Windows 9x, a blue screen appears requesting to insert the disk. I am not sure right now how to solve this problem. If you have ideas, please write to me. SetErrorMode(), doesn’t help here.

Last modified on Wednesday, 20 May 2015 14:43
Data Recovery Expert

Viktor S., Ph.D. (Electrical/Computer Engineering), was hired by DataRecoup, the international data recovery corporation, in 2012. Promoted to Engineering Senior Manager in 2010 and then to his current position, as C.I.O. of DataRecoup, in 2014. Responsible for the management of critical, high-priority RAID data recovery cases and the application of his expert, comprehensive knowledge in database data retrieval. He is also responsible for planning and implementing SEO/SEM and other internet-based marketing strategies. Currently, Viktor S., Ph.D., is focusing on the further development and expansion of DataRecoup’s major internet marketing campaign for their already successful proprietary software application “Data Recovery for Windows” (an application which he developed).