I asked VMWare to provision my disk to be larger and then asked Linux to refresh the kernel info:

 $ echo 1 > /sys/class/scsi_device/0\:0\:3\:0/device/rescan 
 $ dmesg
 sdd: Write Protect is off 
 sdd: Mode Sense: 61 00 00 00 
 sdd: cache data unavailable 
 sdd: assuming drive cache: write through 
 sdd: detected capacity change from 171798691840 to 343597383680

I added another partition and then tried to get LVM to use it:

$ fdisk /dev/sdd
 Command (m for help): n
 Command action
 e extended
 p primary partition (1-4)
 p
 Partition number (1-4): 3

But LVM couldn’t see it:

 $ pvcreate /dev/sdd3
 Device /dev/sdd3 not found (or ignored by filtering).
 $ pvcreate -vvvv /dev/sdd3
 #device/dev-cache.c:578 /dev/sdd3: stat failed: No such file or directory
 #metadata/metadata.c:3546 
 #device/dev-cache.c:578 /dev/sdd3: stat failed: No such file or directory

The solution was to use partprobe to inform the OS of partition table changes:

 $ partprobe /dev/sdd
 $ pvcreate /dev/sdd3
 dev_is_mpath: failed to get device for 8:51
 Writing physical volume data to disk "/dev/sdd3"
 Physical volume "/dev/sdd3" successfully created

We need to find the salt (the last four bytes of the hash), and then concatenate PASSWORD+SALT, take the SHA hash, convert to base64, prepend {SSHA}, and then finally base64 encode that whole string again.

Here is what ldapsearch says is the password hash:

userPassword:: e1NTSEF9OWZ1MHZick15Tmt6MnE3UGh6eW94SDMrNmhWb3llajU=

The first step is to retrieve the (binary) salt which is stored at the end of a double base64 encoded hash.  I wrote a perl SSHA Salt Extractor for that:

$ cat getSalt.pl
#!/usr/bin/perl -w

my $hash=$ARGV[0];
# The hash is encoded as base64 twice:
use MIME::Base64;
$hash = decode_base64($hash);
$hash=~s/{SSHA}//;
$hash = decode_base64($hash);

# The salt length is four (the last four bytes).
$salt = substr($hash, -4);

# Split the salt into an array.
my @bytes = split(//,$salt);

# Convert each byte from binary to a human readable hexadecimal number.
foreach my $byte (@bytes) {
$byte = uc(unpack "H*", $byte);
print "$byte";
}
$ ./getSalt.pl e1NTSEF9OWZ1MHZick15Tmt6MnE3UGh6eW94SDMrNmhWb3llajU=
68C9E8F9

See, that is four ASCII characters represented by human readable hexadecimal. Another way to do this is like this:

echo "e1NTSEF9OWZ1MHZick15Tmt6MnE3UGh6eW94SDMrNmhWb3llajU=" | base64 -d | sed 's/^{SSHA}//' | base64 -d | tail -c4 | od -tx1

Now that we have extracted the salt, we can regenerate the salted hash with what we think the password should be.

$ cat openldap-sha.pl
#!/usr/bin/perl

use Digest::SHA1;
use MIME::Base64;

my $p=$ARGV[0];
my $s=$ARGV[1];

# Convert from hex to binary.
$s_bin=pack 'H*', $s;

# Hash the password with the salt.
$digest = Digest::SHA1->new;
$digest->add("$p");
$digest->add("$s_bin");

# Encode PASSWORD+SALT as Base64.
$hashedPasswd = '{SSHA}' . encode_base64($digest->digest . "$s_bin" ,'');

# Encode as Base64 again:
print 'userPassword:: ' . encode_base64($hashedPasswd) . "\n";

$ ./openldap-sha.pl correcthorsebatterystaple 68C9E8F9
userPassword:: e1NTSEF9OWZ1MHZick15Tmt6MnE3UGh6eW94SDMrNmhWb3llajU=

And there you have it.

I’m staring at my LCD module.  I can hear it saying, “hook me up!”, but I’ll have to read a bit first.

#1: Identification

On the back of the unit, it says:
AMC2004A-B-B6NTDW-SP LOT#000542

A little Googling for “AMC2004A-B” and I find that it’s an HD44780 compatible LCD.  I find a PDF spec sheet and even an Arduino library:

http://www.shopeio.com/inventory/pdf/AMC2004A.pdf
http://arduino.cc/en/Reference/LiquidCrystal

#2: Figuring

The only figuring I need is for the backlight.  The spec says that for the white backlight, I should use 4.0V at 30mA.  I have a 5V supply so, with Ohm’s Law in mind, the math goes:
R   =   V/I   =   Rdrop/series_current   =   (5V-4V)/30mA   =   33Ω

#3: Wiring
A little skimming of the spec sheet helps me understand how to wire this up so here we go:

#4: Programming

The LiquidCrystal Library came with my Arduino 0012 Alpha software package (IDE).   A couple of modifications to the Hello World Example: