use strict;
use warnings;

my $file_name = 'G:\\I386\\DRIVER.CAB';  # 50MB file.

open(my $fh, '<', $file_name)
   or die("Unable to open file \"$file_name\": $!\n");

my $buf;
my $rv;

$rv = sysread($fh, $buf='', 1);
print("On success, ");
if (defined($rv)) {
   print("\$rv = $rv\n");
} else {
   print("\$rv is not defined\n");
}

print("Eject the media then press Enter.");
<STDIN>;

1 while $rv = sysread($fh, $buf='', 1);
print("On failure, ");
if (defined($rv)) {
   print("\$rv = $rv\n");
} else {
   print("\$rv is not defined\n");
}

close($fh)
   or warn("Unable to read file \"$file_name\": $!\n");