Gav's Blog

Recently, I needed to tweak the guest user on my Mum’s laptop so that visitors weren’t sharing the account that they use for email and the like. Unfortunately the Guest account that comes with OS X 10.5 is not ideally configured so I needed a way to customise it to make it more friendly for guests. There is a ‘Simple Finder’ option, but it was a bit too simplistic for my needs. Anyway, I found a nice little writeup that shows how to tweak the Guest account’s configuration to make it a bit more guest friendly.

As I write this, my home Mac has just about finished receiving a hard drive upgrade. I had approach the 250GB hard drive’s limit and was needing something far bigger – mainly for photos and movies from my camera.I had read online a few blogs that performed the upgrade by simply making sure that the Time Machine backup was up-to-date, and then removing the old hard drive, installing the new one, booting the OS X installer DVD, formatting the drive and restoring from backup. Sounded like a great option so I thought I’d give it a go to install a nice shiny 1TB hard drive.This blog post noted that the restore process was extremely slow. I had a quick restore with around 230GB being restored in around 2.5 hours. The expected time was a lot slower initially, I think this was because the system files were copied first, and this included a lot more small files that have more overhead associated with reading and writing than say transferring a digital photo or movie – e.g. one 10MB file is faster than transferring 1000 1KB files.It is just booting now, so I’ll know very soon whether it worked or not… stunning it has appeared to work perfectly. Now I just have to wait for Spotlight to re-index everything. But other than that, it was a painless upgrade.It also served an excellent dual purpose of actually testing that the restore process works. Very useful!Now I need to look at setting Time Machine to backup to multiple drives. It sounds like it can be done. 

I had downloaded Fedora Core 8 to install on one of our work servers, and I noted that only sha1sum’s are provided to verify the downloaded iso now. In the past I had used md5sums and had installed md5sum on my Mac to achieve this. Anyway, it turns out there is a simple solution to verify the file anyway. 

openssl dgst -sha1 Fedora-8-i386-DVD.iso

From the 300+ features announced in OS X 10.5 (courtesy of SlashGeo), one that I really like the sound of is that Preview will now recognise and make use of georeferenced digital photos – photos that have latitude and longitude incorporated in them.

GPS Metadata Support
Get real information from your photos. If your image has embedded GPS metadata, Preview will show you exactly where that perfect photo was taken. Open the Image inspector and select GPS. Preview pinpoints the location where you took the photo on a world map. From there you can even open the GPS location in Google Maps.

Of course, not many digital cameras support GPS at this point, but there are a number of ways to add lat/long information to photos when post-processing. I recently purchased a very small GPS tracker that I can mount on my camera and it generates a tracklog that can then be matched up with the timestamp in a photo to estimate where the camera was at a given point in time. I am interested in this not only for hobby photography, but also as an application during disasters using this setup for Disaster Impact Assessment and being able to easily produced georeferenced photos of damaged infrastructure for example.