Mike: Technical: September 2011 Archives

Recently I was doing some work with GNU GRUB and noticed some really cool features that were new to me! Wow, how things can change!

Of course the reason that it changed was that I was looking at the documentation for GRUB, not GRUB Legacy.

Bummer. I was looking forward to the use of the 'ls' command too!

So why did I want GRUB Legacy documentation and not GRUB docs? Of the three "top" Enterprise Linux distributions only Ubuntu currently ships GRUB. Both SUSE and Red Hat use GRUB Legacy. Oh well. There was some cool stuff I found though.

Aside from the 'ls' command being available one of the other advantages to GRUB that I am waiting to see with Red Hat and SUSE is the ability to use a software raid and/or LVM boot device. Until they implement the newer revision of GRUB you will still have to create a separate /boot partition. Such a bummer.

There were a few other cool items that I saw and thought were worth a mention (lifted directly from the GFD Licensed online manual, see links below):

14.3.32 parttool

-- Command: parttool partition commands

Make various modifications to partition table entries.

Each command is either a boolean option, in which case it must be followed with '+' or '-' (with no intervening space) to enable or disable that option, or else it takes a value in the form 'command=value'.
Currently, parttool is only useful on DOS partition tables (also known as Master Boot Record, or MBR). On these partition tables, the following commands are available:
'boot' (boolean)
When enabled, this makes the selected partition be the active (bootable) partition on its disk, clearing the active flag on all other partitions. This command is limited to primary partitions.
'type' (value)
Change the type of an existing partition. The value must be a number in the range 0-0xFF (prefix with '0x' to enter it in hexadecimal).
'hidden' (boolean)
When enabled, this hides the selected partition by setting the hidden bit in its partition type code; when disabled, unhides the selected partition by clearing this bit. This is useful only when booting DOS or Wwindows and multiple primary FAT partitions exist in one disk. See also DOS/Windows.

14.3.35 play

-- Command: play file | tempo [pitch1 duration1] [pitch2 duration2] ...

Plays a tune
If the argument is a file name (see File name syntax), play the tune recorded in it. The file format is first the tempo as an unsigned 32bit little-endian number, then pairs of unsigned 16bit little-endian numbers for pitch and duration pairs.
If the arguments are a series of numbers, play the inline tune.
The tempo is the base for all note durations. 60 gives a 1-second base, 120 gives a half-second base, etc. Pitches are Hz. Set pitch to 0 to produce a rest.

And one of my favorites: