When you do get a working tape drive, here is an example of read making the next write 'go bad'...
Fixed Blocks... which I don't use... (Use a parameter on testtape.exe to test both cases.)
Jason.
ps. Why did it get a protection-fault? maybe it's the cygwin1.dll snapshot, but I only get it with *that* example where the API is failing.
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run1: fixed-block, with 'proper' reads of block-length c:\testtape
Opening Tape Handle stblk.mt_blkno=0 ST0: Status: 41030000 BOT ON-LINE Setting length 512 records. rc=0 ST0: Status: 41030000 BOT ON-LINE rewind... rc=0 ST0: Status: 41030000 BOT ON-LINE write... rc=512, errno=0 ST0: Status: 01030000 ON-LINE stblk.mt_blkno=1 backspace... rc=0 ST0: Status: 41030000 BOT ON-LINE stblk.mt_blkno=0 read... rc=512, errno=0 AC23456789 ST0: Status: 01030000 ON-LINE stblk.mt_blkno=1 write... rc=512, errno=0 ST0: Status: 01030000 ON-LINE stblk.mt_blkno=2 backspace... rc=0 ST0: Status: 01030000 ON-LINE stblk.mt_blkno=1 read... rc=512, errno=0 BD23456789 ST0: Status: 01030000 ON-LINE stblk.mt_blkno=2 rewind... rc=0 ST0: Status: 41030000 BOT ON-LINE Closing Tape Handle
run2: with first-read only reading 1 character: c:\testtape read1
Opening Tape Handle stblk.mt_blkno=0 ST0: Status: 41030000 BOT ON-LINE Setting length 512 records. rc=0 ST0: Status: 41030000 BOT ON-LINE rewind... rc=0 ST0: Status: 41030000 BOT ON-LINE write... rc=512, errno=0 ST0: Status: 01030000 ON-LINE stblk.mt_blkno=1 backspace... rc=0 ST0: Status: 41030000 BOT ON-LINE stblk.mt_blkno=0 read1... rc=1, errno=0 A ST0: Status: 01030000 ON-LINE stblk.mt_blkno=1 write... rc=512, errno=0 ST0: Status: 01030000 ON-LINE stblk.mt_blkno=2 backspace... rc=0 ST0: Status: 01030000 ON-LINE stblk.mt_blkno=1 read... rc=-1, errno=28
ST0: Status: 01030000 ON-LINE
stblk.mt_blkno=2
rewind... rc=0
ST0: Status: 41030000 BOT ON-LINE
Closing Tape Handle
9 [main] testtape 102 handle_exceptions: Exception: STATUS_ACCESS_VIOLATION
6056 [main] testtape 102 open_stackdumpfile: Dumping stack trace to testtape.exe.stackdump
//#include <io.h> #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <sys/mtio.h>
int fh; struct mtget stblk; struct mtop opblk;
#define BLKLEN 512 #define RBLKLEN 512 //#define RBLKLEN 65535 // var blks only
char buf [BLKLEN] = "0123456789";
void disp_stat () {
int stat;
char buf [256];ioctl (fh, MTIOCGET, (char*)&stblk); stat = stblk.mt_gstat;
/* Display tape status */ sprintf (buf, "Status: %8.8X", stat); if (GMT_EOF(stat)) strcat (buf, " EOF"); if (GMT_BOT(stat)) strcat (buf, " BOT"); if (GMT_EOT(stat)) strcat (buf, " EOT"); if (GMT_SM(stat)) strcat (buf, " SET-MARK"); if (GMT_EOD(stat)) strcat (buf, " EOD"); if (GMT_WR_PROT(stat)) strcat (buf, " WR-PROT"); if (GMT_ONLINE(stat)) strcat (buf, " ON-LINE"); if (GMT_D_6250(stat)) strcat (buf, " 6250"); if (GMT_D_1600(stat)) strcat (buf, " 1600"); if (GMT_D_800(stat)) strcat (buf, " 800"); if (GMT_DR_OPEN(stat)) strcat (buf, " NO-TAPE");
printf ("ST0: %s\n", buf);
};void common () {
printf ("stblk.mt_blkno=%d\n", stblk.mt_blkno);
};void set_blk (int len) {
int rc; if (len)
printf ("Setting length %d records.", len);
else
printf ("Setting variable records.");
fflush (stdout);opblk.mt_op = MTSETBLK; opblk.mt_count = len; rc = ioctl (fh, MTIOCTOP, (char*)&opblk);
printf (" rc=%d\n", rc);
};void my_read (int fh) {
int rc;
int en;
char buf2 [RBLKLEN]; printf ("read...");
fflush (stdout);
memset (buf2, ' ', 10);errno = 0; rc = read (fh, buf2, RBLKLEN); en = errno;
printf (" rc=%d, errno=%d\n", rc, en);
buf2 [10] = 0;
printf ("%s\n", buf2);
disp_stat ();
common ();
};void my_read1 (int fh) {
int rc;
int en;
char buf2 [1]; printf ("read1...");
fflush (stdout);
memset (buf2, ' ', 10);errno = 0; rc = read (fh, buf2, 1); en = errno;
printf (" rc=%d, errno=%d\n", rc, en);
buf2 [1] = 0;
printf ("%s\n", buf2);
disp_stat ();
common ();
};void my_write (int fh) {
int rc;
int en; printf ("write...");
fflush (stdout);errno = 0; rc = write (fh, buf, BLKLEN); en = errno;
printf (" rc=%d, errno=%d\n", rc, en);
disp_stat ();
common ();
};void my_bksp (int fh) {
int rc; printf ("backspace...");
fflush (stdout);
opblk.mt_op = MTBSR;
opblk.mt_count = 1;
rc = ioctl (fh, MTIOCTOP, (char*)&opblk);
printf (" rc=%d\n", rc);
disp_stat ();
common ();
};void my_rew (int fh) {
int rc; printf ("rewind...");
fflush (stdout);
opblk.mt_op = MTREW;
opblk.mt_count = 1;
rc = ioctl (fh, MTIOCTOP, (char*)&opblk);
printf (" rc=%d\n", rc);
disp_stat ();
};int main (int argc) {
int rc;printf ("Opening Tape Handle\n");
fh = open ("/dev/st0", O_RDWR);
if (fh >= 0) { rc = ioctl (fh, MTIOCGET, (char*)&stblk);
if (rc < 0) {
printf ("Failed to IOCTL the Tape\n");
} else {
common ();
}; disp_stat ();
set_blk (BLKLEN);
disp_stat ();
my_rew (fh); buf [0] = 'A';
buf [1] = 'C';
my_write (fh);
my_bksp (fh); if (argc == 1)
my_read (fh);
else
my_read1 (fh); // special 1 char read buf [0] = 'B';
buf [1] = 'D';
my_write (fh);
my_bksp (fh);
my_read (fh);
my_rew (fh); printf ("Closing Tape Handle\n");
close (fh);} else {
printf ("Failed to Open Tape\n");
};return (0); };
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