8bit nostalgia

Over the last few days I've been browsing sites dedicated to the old 8bit BBC micro made by Acorn computers in the 1980s. I was first exposed to the BBC at primary school where I think they had two of them (for the entire school!). When I reached secondary school, I joined the break and lunchtime "Computer Club".

At home we had an Acorn Electron. This was a cut down version of the BBC that ran at a slower speed (1Mhz vs 2Mhz), only a single channel for sound and missed the memory efficient Mode 7 screen mode. This did not deter me from adding a printer, disc drive and some ROM cartridges (for word processing and spreadsheets). My Dad then used the machine to write up notes and sermons.

At school I used the Acorn Archimedes (the first RISC computer available to the masses) but for home use I eventually got a 286 PC and he upgraded to a BBC Master - the pinnacle of BBC 8bit computing.

This would have been in about 1993. So why blog about it now?

I'm realising in my browsing just how well designed the BBC was. No other machine had the potential for expansion or the fantastic BBC BASIC. The implementation of BASIC was beyond all other 8bit micros and had named procedures and an inbuilt assembler. The operating system (16k!) provided access to the hardware in a very simple way.

The BBC could have benefited from some better graphics (say 16 colours at a 320x256?) and a beefed up sound chip (it's not bad, but not as powerful as the SID in the C64), but it remains to this day a classic machine that can stand proudly among its peers.

I must visit my parents and hunt down the BBC Master...

VMware Server Performance Issue

I've been running VMware Server on the SilverShuttle for a while now (140 days and counting!). The little machine is generally running very well with its two VMs - Solaris Nevada and CentOS, but occasionally the machine stutters very badly and the load average within the virtual machines shoot up from the 0.1 they usually are to about 40.0!

Unfortunately, running top and prstat did little to suggest any reason, and the host operating system (SUSE 10.1) didn't seem to be having any problems of its own apart from the VMware processes which were now taking a lot more CPU.

Cutting to the conclusion, after a period of investigating what might be the cause, I turned off the powersaved daemon on the host operating system. Since then, performance has been rosy. I'm guessing the powersaving was kicking it, misreporting the CPU speed to the VMs which were then choking (but it's just a theory).

All is now well.

Installing Alfresco

A week ago I decided to install the Alfresco open source enterprise content management system on my CentOS VM. The basic install is very easy, comprising of creating /opt/alfresco and untarring the downloaded file into it. The demo version uses HSQL as a content repository, but this isn't recommended for production use.

I opted to change the datasource to MySQL and after setting up the database (using the script provided), I had problems starting the Alfresco installation. I then ran out of time and abandoned it.

Today I went back to the install and after doing some reading up, found that the problem was due to changing the content repository from HSQL to MySQL. As I had no content to worry about, I deleted /opt/alfresco and reinstalled. The big difference this time being that I did not start the installation before I changed the settings to MySQL.

And it works! I now need to learn how to use it, but it appears to be a very powerful piece of software. More blogging soon...

Reflections on the Macworld Keynote

I subscribe to the notion that the Macworld Keynote is one of the most important presentations in the IT industry. This is because Apple have a unique ability to create very smart and easy to use products that appeals to non-technical people, while also creating kit that geeks enjoy using (the number of MacBooks being used at the UK Unix User Group was testament to that).

Last year was the iPhone, which although not being a perfect product (lack of 3G for example) has shaken the mobile market so much that every other mobile company is having to up their game. Apple was also a significant influence in leading the music industry to drop DRM.

The buzz at this year's presentation is surrounding the MacBook Air. But in my mind, the biggest news is the upgraded Apple TV. When this was released last year, the Apple TV was pushed as being an iPod for the living room. This year, Steve Jobs admitted that the product didn't meet expectations, but they were revisiting it. The big news was the introduction of movie rentals.

iTunes Movie Rentals provides a way to download movies from iTunes straight from the TV with no computer being required. These movies can then be saved for 30 days and once started, you can play it for 24 hours. If this works for rentals, then presumably the next step would be purchases over the Internet. This could make the HD-DVD vs BluRay conflict completely irrelevant. The number of Playstation 3s will ensure that BluRay has some future, but perhaps the convenience of online purchase of movies will mean BluRay won't automatically replace DVD as the de facto format.

Regarding the MacBook Air - it really is thin and the multitouch demo was very impressive. It's not something I'd be interested in getting, but I can appreciate there will be a lot of people who will want one.

So although this year there was nothing to top last year's iPhone announcement, the potential for the upgraded Apple TV could be as disruptive to the media world as the iPhone has been to the mobile phone industry. Let's see how everyone else responds...

Updating the backup process

When I upgraded from OpenSUSE 10.1 to 10.3, I took the decision to migrate away from XFS and use EXT3. Although XFS had served me well for many years, I felt the simplicity of using the "standard" Linux filesystem would make restores easier. For large filesystems with high throughput, XFS is fantastic, but for more home workstation, I don't think there is much in it. Actually, if anything, EXT3 is more responsive when doing a backup.

In making the change, I had to modify my backup scripts to use ext3 dump instead of xfsdump. This gave me the chance to revisit the LVM snapshot section I wrote a few years ago, but could not get working with the kernel supplied with 10.1 (It worked. Sometimes).

The new script is very simple and does the following:

1) Takes a filesystem to dump and dump level to take (0 = full, 1=everything that has changed since the last level 0, 2=everything that has changed since the last level 1 etc.).
2) Works out the underlying LVM logical volume the filesystem is built on.
3) Creates a snapshot of the logical volume and mounts in under /snapshot
4) Performs a dump of /snapshot to my external (Firewire) hard disk.
5) Umounts /snapshot and destroys the snapshot.

It appears to be working pretty well and provides what should be a very simple mechanism for ensuring my main workstation is backed up.

T's Vista PC is backed up to another external Firewire hard disk using the built in Vista tools. This appears to do the job and happens automatically, so it's a fire-and-forget operation.

I'm not currently backing up the Mac. This shouldn't be a problem because all my important files are stored on the network. It also seems that Time Machine has some limitations (setting backup schedules, limited to using local storage etc.). I'm guessing a future version of Mac OS X will fully support ZFS and will use ZFS snapshots for backing up.

This leaves the "SilverShuttle" which is my VMware Server / Solaris server. This needs some form of backup and I'm still chewing over the options. I'd ideally like a large external array with a bunch of disks that are managed by ZFS, but this doesn't solve my desire to keep an off-site copy of my data. Something for me to work on then...

A solution to wireless hassles: Ethernet over mains

I have all my computers upstairs in our office (second bedroom), but the telephone enters the house downstairs in the lounge. For the last few years, I've put the ADSL router (Netgear 834G) in the corner and connected to the upstairs using a Wireless Ethernet Bridge (Netgear WGE101). This worked pretty well at first - until I started getting neighbours with wireless!

I first realised that those around me were getting wireless connections when my own LAN kept losing the router. This was quickly fixed by me changing my channel to something unused, but random connection problems still persisted.

The other night I stared in bemusement as the Wireless Bridge claimed a 99% signal strength to the access point on my router, but refused to connect. I remembered a conversation I had with a colleague a few weeks previous where he mentioned that he had installed Ethernet over mains power.

So after T finished watching an episode of Desperate Housewives, I flicked the switch in the fuse box labelled "sockets" and observed that all mains sockets went out - both downstairs and upstairs - indicating that I had a single ring main.

A few minutes later, everything was back (the computers never went down thanks to the UPS! :-)) and I was ordering the Devolo HomePlug Adapter "Highspeed Starter Kit". This arrived last night and consisted of two RJ45 cables and two adapters that plug into the wall socket and have an Ethernet port.

One went downstairs and I plugged the router into it, and the other went upstairs into a four way expansion unit that was not connected to the UPS (I'm guessing that the UPS will clean the signal and could potentially interfere with the Ethernet, but haven't tried it). A few seconds later, and it was all working!

There is some software that can be used to set a custom encryption password for the mains side, and there is even a Linux version included on the CD, but I haven't bothered with it yet.

The unit is rated at up to 85Mbits which is still much faster than the 8Mbit bottleneck of the ADSL connection.

It was running all last night and so far, I am very impressed. The whole thing cost about £80 from Amazon and means I should no longer have to experience the woes of losing a wireless connection at home.

OpenSUSE 10.3 upgrade and DNS fun

Over the last couple of days I've been busy tweaking my network. I've updated my main workstation from OpenSUSE 10.1 to 10.3 (having missed 10.2 completely). The new version is pretty decent and shows the continuing refinement of Linux as a desktop operating system.

The GNOME "slab" menu is pretty decent and works well. The confusion over the different software management tools (YAST vs Zenworks basically) has been resolved with a new look and feel to the software management tool. I'm not as impressed with it as the previous version as the interface is less informative, but it does work.

Getting Compiz working (for wobbly windows fun) was easy, although getting Compiz Fusion setup was more difficult. I experienced the unhelpful white screen when enabling XGL, but the Nvidia driver apparently does not need XGL for accelerated graphics, and the new whizzy effects are certainly pretty impresive (although the more advanced ones like Burn and Explode are a bit jerky on my old 5200FX graphics card).

With the number of virtual machines on my network now increasing, I was getting tired of looking up IP addresses in /etc/hosts and decided to build myself a small DNS server Solaris zone. Setting up BIND is one of those things that I always think is hard, but whenever I do it, I surprise myself how easy it is.

I opted to setup a dedicated zone because, well, the overhead is minimal and it provides a nice way of separating services. I built "dnsserver" as a sparse root zone, created /var/named and setup the zones files and /etc/named.conf. Now to be honest, I did cheat a little by using the h2n script to generate the zone information automatically, but having done that I then manually tweaked all the entries to get my A (authorative) and CNAME (canonical) entries setup correctly. A few more minutes spent on reconfiguring my other machines to use the DNS server and my "local.zone" was up and running.

I've also made tentative steps into the world of LDAP by installing Fedora Directory Server into a Centos 5.1 virtual machine. Having completed the install, I tried to setup an LDAP user, but have so far failed to get this working. Something to pick up when I have more time.

I'm still working on consolidating all my documents into a single fileserver, possibly using an iTunes server for sharing music. Will update when I've done more...