For a while, I have been considering building a NAS to add to my network. I have a laptop which I mostly interact with, a virtual machine which is my main 24/7 server, a desktop on which I play games, and a number of other devices dotted around. While the desktop has plenty of storage, it’s rarely on. And while the virtual machine is on all the time, I don’t want to use too much of the disk space on the host (mainly so that it can be used for other things).

Additionally, my little Fit-PC box is starting to play up, so I want something that is easier to repair than it is.

—–BEGIN PGP SIGNED MESSAGE—– Hash: SHA512

Date: 2015-03-10

For a number of reasons, I’ve recently set up a new OpenPGP key, and will be transitioning away from my old one.

The old key will continue to be valid for some time, but I prefer all future correspondence to come to the new one. I would also like this new key to be re-integrated into the web of trust. This message is signed by both keys to certify the transition.

“How long does my password have to be to be uncrackable?”

This question was asked recently on IRC. The person asking it was, no doubt, expecting a simple answer such as “20 characters” or “32 letters, numbers, and punctuation”, but I wondered if there was a proper answer to this.

So, let’s start with some background. What do we mean by and “uncrackable password”? We immediately dicounted the trivial solution of cracking the password by knowing it. So, we’ll go with the usual problem of “brute-forcing” the password. This involves checking one password, then the next, then the next; if your password was a number, brute forcing would start at 1, then try 2, then 3 and so on. For any given number of possibilities, the average password will be found in half the tries.

I use tmux quite heavily on my server now. I like it so much, in fact, that I have my shell configured to connect to (or start) a session as soon as I log in. So, however I log in (at the console, in a terminal emulator, via SSH), I always get the same view of my command lines. However, one issue that’s been bugging me for a year is a problem with entering SSH passphrases to the SSH agent.

TWRP is a recovery image for Android devices. That is, it’s a tiny, self-contained operating system that you can boot to (often, by holding a button while booting the device) and perform operations such as backups, restores and installation of other images. One nice feature of TWRP is that it’s quite flexibly themeable; the theme’s aren’t just re-colours, you can move buttons around quite a bit.

Now, most of the instructions I’ve seen for installing a theme consist of the following:

As I mentioned earlier, I have a small (embedded style) computer that I want to use for some monitoring. My suspicion is that the SSD that’s fixed into it is causing problems, so I want to be able to boot the computer diskless (that is, I want to load the Operating System over the network).

Diskless booting is a task that’s not very common, but the idea of it has been around for quite a while. Back when storage was expensive but networking was cheaper, diskless workstations were available which could only boot in this manner. The typical process by which diskless booting happens is as follows.

Well, I’ve managed to knock down one of the tasks that’s been on my “TODO” list for a while, thanks to finding someone building PDNS debs from git.

Background

I live with another geek. When we moved in together, both of us had our own domains, with DHCP servers giving out addresses for the computers we own. As we brought the computers together, the easiest solution was to run as normal, but turn off the “authoritative” function of the two DHCP servers. By doing that, both servers see the DHCP request; one will not know the host, so won’t respond, allowing the other one to supply an address. It was a little clunky but it worked.

We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil.

— Donald Knuth

As part of updating my Wordpress Installation for the arrival of https://paulsaunders.org.uk, I decided I’d need to add some caching in order to cope with the extra visitors. In addition, with it being a Multisite, I figured there’d be some common assets which could be cached nicely between the different sites.