Description of the Full Copy read mechanism, console output and logfile content

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Contents: Read mechanism | Console output | Logfile content

Read mechanism

For a fast copy process the file to copy is read in blocks of 64 KB. If a not readable part is detected the block size is decremented step by step down to 512 bytes, so that as much data as possible can be read successfully. Defective parts are scanned in blocks of 512 bytes until a readable block occours. After that the block size is incemented up to 64 KB again.

The small block size of 512 bytes will lead to very slow execution especially if the noit readable part is very long. For example, a defective part of 64 KB will be divided into 128 blocks to scan. But here is an advantage. If a defective part containes some blocks that are readable this blocks will surely be detected.

Console output

Progress information and defective parts will be shown during the whole copy process. This can result in an output like shown in the example below:

1 Full Copy v0.1 build 2004/12/28, (C)2002-2004 by Michael Berthold

2 Visit for info

3 task: copy 78414084 bytes from 'M:\Files\Video.mpeg' to 'C:\Temp\Video.mpeg'

4 err23: reading failed for 4096 bytes at position 0x13B000

5 err23: reading failed for 12800 bytes at position 0x147200

6 err23: reading failed for 12288 bytes at position 0x152000

7 err23: reading failed for 9216 bytes at position 0x15C400

8 >> bs:512 r:1467392 s:5632

Lines 1 and 2 show general information about the application. The file to copy and it's destination is shown in line 3.

In lines 4 to 7 the not readable parts of the file are listed. Every line begins with the error number starting with prefix err. Normally the error nuber will be 23, which identifies a read error (crc error). Next, the number of bytes which could not be read is given. The smallest amount is 512 bytes. The last number is shown in hexadecimal format and it states the position of the defective part inside the file.

The last line is 8. It conains the current progress. The number bs: states the size of the block to read from the file. Next number is r: which states the number of bytes read so far. The last number s: states the number of bytes which could not be read currently.

Logfile content

Next to the copied file a logfile is created which contains a list of all defective parts. The logfile is named like the copied file with the file extension .skiplog added, i.e. Video.mpeg.skiplog.

The content is formated like the console output. It would equal line 4 to 7 in our example above.

Last change of page 2004/12/29, Copyright ©2004 Michael Berthold

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