final cog

It's easy, once you find out how...

sudo aptitude install flashplugin-installer

Thorcom's latest product is the VLR200 vehicle tracking, location and telemetry unit.

I can never find this page without a lot of searching.

http://llvm.org/releases/download.html

http://stackoverflow.com/questions/2363264/how-do-you-manage-an-object-g...

I've been trying to rationalise the way in which I think imperative and functional programming can be brought together. Primarily, this is an exercise in clarifying my thoughts on how I expected Scala to work. (It doesn't work this way, possibly because it would certainly break interoperability with Java, but probably because Scala's author(s) are a lot cleverer than me. This idea probably has implications of which I have not thought.)

I have structured my thoughts as a series of definitions.

After finding that there was no easy way to get immutable collections to 'snapshot' the state of their contained objects, I realised I would have to use only immutable objects. (See the previous post.)

Immutable objects are much more costly to modify (not modify per se, but to create a new object that almost the same as the old one). A new object has to be created on each mutating method call. There is also then the garbage collection which needs to be done.

I did a little informal benchmark:

I'm evaluating Scala and am having a problem with it's immutable collections.

I want to make immutable collections, which are completely immutable, right down through all the contained objects, the objects they reference, ad infinitum.

Is there a simple way to do this?

The code below illustrates what I'm trying to achieve, and a nasty work around (ImmutablePoint).

The UDP Echo Server seems to be the 'hello world' of network programming.

What is Scala?
Scala is a hybrid OO/functional programming language which runs on the Java Virtual Machine.

OpenDungeonMaster

Here's a little Dungeon Master proof-of-concept, written in Javascript, HTML and CSS only. I wrote it to learn more about Javascript and CSS.

In the spirit of 'doing the simplest thing which works', I've been using the following idiom for encapsulating data within objects. I'm still quite new to Javascript, so I'm sure others have been doing similar things for a long time, in a more elegant fashion (I must get round to reading the jQuery source).

A naive object is:

var account = { name    : "fred"
              , balance : 100.00
              , branch  : "Worcester"
              } ;

I read Douglas Crockford's book and was rather inspired.

Now JavaScript is starting to grow up, with excellent projects including env-js, nodeJS, CommonJS, v8 and jQuery, what are the reasons to still use other 'scripting' languages. (I'm not using 'scripting' in a derogatory way - I suppose I mean dynamic/interpreted.)

I upgraded my laptop today. When I restarted, it gave me that dreaded choice of 'low-graphics mode'. X was well and truly borked.

The error was:

(II) Module nvidia: vendor="NVIDIA Corporation"  compiled for 4.0.2, module version = 1.0.0 
FATAL: Module nvidia not found. 
(EE) NVIDIA: Failed to load the NVIDIA kernel module. Please check your 
(EE) NVIDIA:     system's kernel log for additional error messages.

The solution was to edit xorg.conf to use the 'nv' driver, reboot, and then use System>>Hardware Drivers to install version 173.

I recently found a need to create a 'debouncer', or 'bistable' object.

This is basically a counter with low and high limits, and a state. When the counter gets to the high limit the state is changed to 'on', when it reaches the low limit, the state is changed to 'off'. Actions can be registered to be executed on either of these state changes.

It seems an ideal, small, but not trivial, object to implement in several languages to document their differences.

Just three weeks after moving into out new house, we received a leaflet through the door. It informed us that 520 new houses are going to built at the end of our road. What a nice moving-in present.

http://www.offenhamroad.org

Oh well, I shouldn't dwell on misfortunes too long... I wonder if the sellers knew?

The hosting environment is assumed to be Ubuntu Jaunty, with qemu already installed.

First, get the files you'll need:

$ wget http://ftp.de.debian.org/debian/dists/lenny/main/installer-armel/current/images/versatile/netboot/initrd.gz
$ wget http://ftp.de.debian.org/debian/dists/lenny/main/installer-armel/current/images/versatile/netboot/vmlinuz-2.6.26-2-versatile

Create a disk image:

$ qemu-img create -f qcow hda.img 10G

Then start qemu:

$ qemu-system-arm -M versatilepb -kernel vmlinuz-2.6.26-2-versatile \

Building History is a newly-launched collaborative project, tasked with producing freely available information about the history of the UK's towns, roads and buildings.

Building History is a wiki. Articles are created in plain text with special tags inserted where needed to present the page in a clear and readable format. There's no need to learn web design or HTML create and edit articles. The Formatting Guide of the help section has information on how to format pages.

This is just to stop me from having to lookup the date command.

ssh root@servername date `date +%m%d%H%M%Y.%S`

It set the date and time on servername to be the same as the local date and time. Obviously ntp is the correct solution here...

Today, while working for ApplianSys, I needed to count how many times an expression was True in an aggregate query.

My query began...

SELECT MAX(reply_size), COUNT(*), req_method, req_scheme, req_hostname, req_port, req_path, req_query, req_fragment, COUNT(cache_status LIKE '%HIT%')

Sqlite3 told me that all of the records were hits (as I misinterpreted the results), which was incorrect.

Background

I have a co-located server for hosting Virtual Machines (KVM and VMWare). These virtual machines use sparse files as their disk images. This saves a huge amount of space, without incurring too much of a slowdown - it also takes away the sysadmin headaches of having to add more disk images when a VM outgrows its initial allocation of space.

Task

I needed to backup these VMs (using LVM2 to get as consistent an image as possible) to a server at home - efficiently.

Fruitless Investigations