Messages in this thread |  | | Date | Tue, 17 Sep 2002 23:58:22 +0200 | From | Rogier Wolff <> | Subject | Re: [Linux-usb-users] Re: Problems accessing USB Mass Storage |
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On Tue, Sep 17, 2002 at 10:13:13PM +0100, Mark C wrote: > On Tue, 2002-09-17 at 21:13, Thomas Dodd wrote: > > > > > Give that a go Mark. > > > > Try a few values like 25, 50, 75, and 100. with bs=1k and > > unset (default 512 byte). > > If I'm reading this correctly, I have been trying: > > [root@stimpy mark]# dd if=/dev/sda of=tmp/tmp.img skip=50 \ > bs=1k dd: reading `/dev/sda': Input/output error > 0+0 records in > 0+0 records out
Guys,
When dd is told to skip a certain number of input blocks it doesn't seek past them, but reads them and then discards them. Thus if you're not supposed to read sectors 1-100 then this will not work.
Try the following program:
/* seek.c (C) R.E.Wolff@harddisk-recovery.nl */ /* gcc -Wall -O2 seek.c -o seek */
#include <stdio.h> #include <unistd.h> #include <string.h> #include <errno.h> #include <sys/types.h>
#ifndef O_LARGEFILE #define O_LARGEFILE 0100000 #endif long long lseek64 (int fd, long long offset, int whence);
int main (int argc,char **argv) { long long off; long long tt;
if(argc < 2) exit(0); /* don't seek at all */
if (strncmp (argv[1],"0x",2) ) sscanf (argv[1],"%Ld",&off); else sscanf (argv[1],"%Lx",&off);
if (argc > 3) { if (strncmp (argv[3],"0x",2) ) sscanf (argv[3],"%Ld",&tt); else sscanf (argv[3],"%Lx",&tt); if (argv[2][0] == '+') off += tt; else off -= tt; } errno = 0; if ((lseek64 (0,off,SEEK_CUR) < 0) && (errno != 0)) perror ("seek"); exit (0); }
with the command:
dd if=/dev/sda of=firstpart
(Get the partition table)
(seek 0x100000;dd of=secondpart) < /dev/sda
Get everything beyond 1Mb. If this works, then we have to figure out how low we can make the "0x100000" number to get all of the data.
Hypothesis: The partition table specifies that the data starts on sector 200, and they didn't implement sectors 1-199..... Cheap basterds.
(My memory stick is just over 128 * 10^6 bytes, and not even close to 128 * 2^20 bytes....)
Roger.
-- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 ** *-- BitWizard writes Linux device drivers for any device you may have! --* * The Worlds Ecosystem is a stable system. Stable systems may experience * * excursions from the stable situation. We are currenly in such an * * excursion: The stable situation does not include humans. *************** - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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