Message-ID: <361273F0.3CB2784@montana.com>
Date: Wed, 30 Sep 1998 12:09:52 -0600
From: bowman <bowman AT montana DOT com>
Reply-To: bowman AT montana DOT com
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To: djgpp-workers AT delorie DOT com
Subject: proposed change to mntent.c
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This is a suggested patch to mntent.c. 

The problem: On a Compaq Presario with one floppy drive, if there was no
diskette in drive a:, the next call would search for drive b:. It would
take
from 30 to 40 seconds for the biosdisk call to return, during which time
the
system would appear to be hung. I presume this problem is unique to the
Compaq
bios.

The solution: Eli suggested reordering the call sequence so that the
A:/B:
drive mapping function was called before the biosdisk. This solves the
problem
on the Compaq, and still corectly recognizes the A: and B: drives on a
ZDS box
that does actually have two floppies. It does not appear that
'assigned_to'
call ever tries to access a physical drive, so I don't think there will
be any
side effects to the code swap, but further testing on other systems
would be
desirable.

Documentation: There are no changes in the usage of the defined
function,
getmntent.






*** src/libc/compat/mntent/mntent.old	Mon Aug 12 23:14:46 1996
--- src/libc/compat/mntent/mntent.c	Wed Sep 23 20:02:10 1998
***************
*** 452,458 ****
    int cds_address_offset;
    /* Need TRUE DOS version. */
    unsigned short true_dos_version = _get_dos_version(1);
! 
    dos_mem_base = _go32_info_block.selector_for_linear_memory;
    our_mem_base = _my_ds();
  
--- 452,458 ----
    int cds_address_offset;
    /* Need TRUE DOS version. */
    unsigned short true_dos_version = _get_dos_version(1);
!   
    dos_mem_base = _go32_info_block.selector_for_linear_memory;
    our_mem_base = _my_ds();
  
***************
*** 546,551 ****
--- 546,561 ----
        if (drive_number == 2 && skip_drive_b)
          continue;
  
+ 
+       /* See whether drive A: is mapped to B: and if it is, change
+          DRIVE_NUMBER on the fly and raise the flag to skip drive
+          number 2 next time we are called (meaning there is only
+          one floppy drive).  */
+       if (drive_number == 1 && (drive_a_mapping = assigned_to(1)) > 0)
+         {
+           skip_drive_b = 1;
+           drive_number = drive_a_mapping;
+         }
        /* Work around a possible bug in QDPMI: _truename() would
sometimes
           crash the calling program when there is no disk in a (floppy)
           drive.  To avoid this, we have to check if the drive is empty
***************
*** 560,582 ****
               operation after disk change, each time resetting the 
               drive, until something other than 6 is returned or we
               run out of our patience.  */
!           while (++count < 10 && (bios_status =
                   biosdisk(2, drive_number - 1, 0, 0, 1, 1, buf)) == 6)
              biosdisk(0, drive_number - 1, 0, 0, 0, 0, NULL);
  
            /* If the loop ends with nonzero status, fail.  */
            if (bios_status != 0)
              continue;
-         }
- 
-       /* See whether drive A: is mapped to B: and if it is, change
-          DRIVE_NUMBER on the fly and raise the flag to skip drive
-          number 2 next time we are called (meaning there is only
-          one floppy drive).  */
-       if (drive_number == 1 && (drive_a_mapping = assigned_to(1)) > 0)
-         {
-           skip_drive_b = 1;
-           drive_number = drive_a_mapping;
          }
  
        drvstr_len = sprintf(drive_string, "%c:\\", '@' + drive_number);
--- 570,582 ----
               operation after disk change, each time resetting the 
               drive, until something other than 6 is returned or we
               run out of our patience.  */
!           while (++count < 2 && (bios_status =
                   biosdisk(2, drive_number - 1, 0, 0, 1, 1, buf)) == 6)
              biosdisk(0, drive_number - 1, 0, 0, 0, 0, NULL);
  
            /* If the loop ends with nonzero status, fail.  */
            if (bios_status != 0)
              continue;
          }
  
 X-Mozilla-Status: 0009rintf(drive_string, "%c:\\", '@' + drive_number);