blgardne@esunix.UUCP (Blaine Gardner) (12/03/86)
Ok, so format does not lock out bad sectors, does DISKCOPY
(CLI or Workbench flavors) do ANY kind of verification on
the data that has been written?
I asked this question a couple of weeks ago and the only
response was a deafening silence on the net.
I have lost several files doing DISKCOPY to unformatted disks,
only to later find one or more I/O errors on the disk. After
running Disksalv I tried to format the bad floppy: no go.
I've had errors ranging from bad sector number to checksum error.
The disk was junk to start with, so why didn't DISKCOPY catch
the errors. It seems to me to be a fatal flaw if there is no
verification of the data written to the disk!
For those with racial bias :-) I've had 3 black (generic trash),
2 dark tan (bulk BASF), and 1 blue (do I dare say it?? sony) fail.
--
=================================================
"The Admiral is well aware of the regulations..."
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Blaine Gardner @ Evans & Sutherland
{ihnp4, decvax}!decwrl!esunix!blgardne
560 Arapeen Drive Salt Lake City, Utah 84108 (801) 582-5847cmcmanis@sun.uucp (Chuck McManis) (12/08/86)
In article <258@esunix.UUCP>, blgardne@esunix.UUCP (Blaine Gardner) writes:
*> Ok, so format does not lock out bad sectors, does DISKCOPY
*> (CLI or Workbench flavors) do ANY kind of verification on
*> the data that has been written?
*>
*> Blaine Gardner @ Evans & Sutherland
Yes it does but effectively No it doesn't. Disassembly of the COPY and
DISKCOPY commands show that they check the return value from the call
to the trackdisk.device, however the trackdisk.device does not check
for anything but the most fatal errors on write (like disk not connected)
It should have a flag for read-after-write verification but it doesn't seem
to. So you are pretty much relying on reliable data transfer.
--
--Chuck McManis
uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.blgardne@esunix.UUCP (Blaine Gardner) (12/10/86)
Thanks for the reply Chuck. Ok, since DISKCOPY doesn't really verify
the data is correct I'm going back to formatting all of my floppys
before using them. I'm tired of loosing data!
Ok C-A when are you going to fix DISKCOPY so that it really does
verify what it has written???
--
=================================================
"The Admiral is well aware of the regulations..."
=================================================
Blaine Gardner @ Evans & Sutherland
{ihnp4, decvax}!decwrl!esunix!blgardne
560 Arapeen Drive Salt Lake City, Utah 84108 (801) 582-5847