Copy with verify per block

With Windows (2000 or XP) is there a way to perform verify and rewrite
as part of copy operations?

What I am looking for is some option where for each e.g. 1MB written it
is check read and rewritten in case of error.

On command line I have tried copy with option /v. This seems to verify
after complete copy. Errors are reported but there are no retry of
writing the blocks found to be wrong.

If not part of Windows is there some utility with copy operation like
that I can use?

This is to debug an unreliable interface not a faulty drive.

TIA, Richard

Previously Richard Foersom wrote:
With Windows (2000 or XP) is there a way to perform verify and rewrite
as part of copy operations?

What I am looking for is some option where for each e.g. 1MB written it
is check read and rewritten in case of error.

On command line I have tried copy with option /v. This seems to verify
after complete copy. Errors are reported but there are no retry of
writing the blocks found to be wrong.

If not part of Windows is there some utility with copy operation like
that I can use?

This is to debug an unreliable interface not a faulty drive.

TIA, Richard

One thing is that this would have to be implemented on a very
low level, maybe the hardware driver. Otherwise it will just
get the date from the buffer-cache and not the device in the
verify. Come to think of it, the /v may very well also get
the copy from the buffer-cache unless the file is larger than
avaliable memory.

As to rewrite on error, I don't think this is available anywhere,
except maybe space-probes and some archiving storage
solutions. Ordinarily write errors are so rare, that typically they do
not call for rewite, but for unit replacement. Also there are many
reasons why a re-write is not a good error recovery strategy. One
exception is some tape technologies, that will verify-read written
blocks with a second head and write again to a different place on the
tape. An other one is MOD drives, were again, the drive does verify
each write and does reallocation and re-write in case of a marginal
read signal. These technologies are designed for long-term storage (I
have an MOD drive) and the error-resilience is implemented in the
drive. The OS never gets to see it, as it typically cannot do this.

As to your problem, I think you may have to disable or bypass the
buffer cache. I am not even sure that is possible. There may be
some option to use a ''raw'' device. An alternative is
to write files so large that they do not fit into memory and then
re-read them.

Arno

Richard Foersom wrote in
With Windows (2000 or XP) is there a way to perform verify and rewrite
as part of copy operations?

What I am looking for is some option where for each e.g. 1MB written it
is check read and rewritten in case of error.

On command line I have tried copy with option /v. This seems to verify
after complete copy. Errors are reported but there are no retry of
writing the blocks found to be wrong.

If not part of Windows is there some utility with copy operation like
that I can use?

This is to debug an unreliable interface not a faulty drive.

Assuming IDE, make sure it runs in UDMA mode.
The interface will not be allowed to corrupt the data.


TIA, Richard

"Richard Foersom" wrote in message
...
With Windows (2000 or XP) is there a way to perform verify and rewrite
as part of copy operations?

What I am looking for is some option where for each e.g. 1MB written it
is check read and rewritten in case of error.

On command line I have tried copy with option /v. This seems to verify
after complete copy. Errors are reported but there are no retry of
writing the blocks found to be wrong.

If not part of Windows is there some utility with copy operation like
that I can use?

This is to debug an unreliable interface not a faulty drive.

TIA, Richard

Why don't you write your own copy program that
1) copies 1MB of data
2) flushes the I/O
3) reads the 1MB from the destination file and compares it
4) repeats until all data is copied?

Regards,
Alvin.

Previously Alvin Andries wrote:

"Richard Foersom" wrote in message
...
With Windows (2000 or XP) is there a way to perform verify and rewrite
as part of copy operations?

What I am looking for is some option where for each e.g. 1MB written it
is check read and rewritten in case of error.

On command line I have tried copy with option /v. This seems to verify
after complete copy. Errors are reported but there are no retry of
writing the blocks found to be wrong.

If not part of Windows is there some utility with copy operation like
that I can use?

This is to debug an unreliable interface not a faulty drive.

TIA, Richard

Why don't you write your own copy program that
1) copies 1MB of data
2) flushes the I/O
3) reads the 1MB from the destination file and compares it
4) repeats until all data is copied?

This will still read from cache.

Arno

"Arno Wagner" wrote in message
...
Previously Alvin Andries
wrote:

"Richard Foersom" wrote in message
...
With Windows (2000 or XP) is there a way to perform verify and rewrite
as part of copy operations?

What I am looking for is some option where for each e.g. 1MB written it
is check read and rewritten in case of error.

On command line I have tried copy with option /v. This seems to verify
after complete copy. Errors are reported but there are no retry of
writing the blocks found to be wrong.

If not part of Windows is there some utility with copy operation like
that I can use?

This is to debug an unreliable interface not a faulty drive.

TIA, Richard

Why don't you write your own copy program that
1) copies 1MB of data
2) flushes the I/O
3) reads the 1MB from the destination file and compares it
4) repeats until all data is copied?

This will still read from cache.

Arno

Can't you flush the cache like "sync" under UNIX? I think I recall a command
to do this for removable storage.

Alvin.

"Alvin Andries" wrote in message
...

"Arno Wagner" wrote in message ...

Why don't you write your own copy program that
1) copies 1MB of data
2) flushes the I/O
3) reads the 1MB from the destination file and compares it
4) repeats until all data is copied?

This will still read from cache.

Arnie is a certified moron.

In Windows, use FILE_FLAG_NO_BUFFERING to bypass the OS cache.
However, the disk can still read from the cache (several MB now),
and only SCSI has an option to bypass the cache on reads. Does SATA2?

Can't you flush the cache like "sync" under UNIX? I think I recall a command
to do this for removable storage.

Safe Removal, or SysInternal's sync.

Previously Alvin Andries wrote:

"Arno Wagner" wrote in message
...
Previously Alvin Andries
wrote:

"Richard Foersom" wrote in message
...
With Windows (2000 or XP) is there a way to perform verify and rewrite
as part of copy operations?

What I am looking for is some option where for each e.g. 1MB written it
is check read and rewritten in case of error.

On command line I have tried copy with option /v. This seems to verify
after complete copy. Errors are reported but there are no retry of
writing the blocks found to be wrong.

If not part of Windows is there some utility with copy operation like
that I can use?

This is to debug an unreliable interface not a faulty drive.

TIA, Richard

Why don't you write your own copy program that
1) copies 1MB of data
2) flushes the I/O
3) reads the 1MB from the destination file and compares it
4) repeats until all data is copied?

This will still read from cache.

Arno

Can't you flush the cache like "sync" under UNIX? I think I recall a
command to do this for removable storage.

This does flush the buffer to disk, but does not clear the read cache.
I am not aware of eny command that emties the read cache.

Arno

Arno Wagner wrote in
Previously Alvin Andries wrote:
"Arno Wagner" wrote in message ...
Previously Alvin Andries wrote:
"Richard Foersom" wrote in message ...
With Windows (2000 or XP) is there a way to perform verify and rewrite
as part of copy operations?

What I am looking for is some option where for each e.g. 1MB written
it is check read and rewritten in case of error.

On command line I have tried copy with option /v. This seems to verify
after complete copy. Errors are reported but there are no retry of
writing the blocks found to be wrong.

If not part of Windows is there some utility with copy operation like
that I can use?

This is to debug an unreliable interface not a faulty drive.

TIA, Richard

Why don't you write your own copy program that
1) copies 1MB of data
2) flushes the I/O
3) reads the 1MB from the destination file and compares it
4) repeats until all data is copied?

This will still read from cache.

Arno

Can't you flush the cache like "sync" under UNIX? I think I recall a
command to do this for removable storage.

This does flush the buffer to disk, but does not clear the read cache.

I am not aware of eny command that emties the read cache.

That's nicer words for you being clueless, babblebot.
The system cache is not the problem as long you can bypass it.


Arno

Folkert Rienstra schreef in berichtnieuws
ws.net...

Can't you flush the cache like "sync" under UNIX? I think I recall a
command to do this for removable storage.

This does flush the buffer to disk, but does not clear the read cache.

I am not aware of eny command that emties the read cache.

That's nicer words for you being clueless, babblebot.
The system cache is not the problem as long you can bypass it.

Dear Folkert,

Although your claim is quite true its allso quite worthless to the
poster(s), in more ways than one :

Apart from making it look like you know something the poster(s) do(es) not,
*but not posting that information*, you allso use a condition in your
statement that could, for all we know, evaluate to "false".

You seem to have no problem with defining the a poster as "clueless". But
than how should we define you ? Especially when seeing that your
bad-mouthing is your *only* response in this thread.

Regards,
R.Wieser