Frequently Asked Questions (and their answers...)
Do I need to a Nereus server to join?
No, you can connect any clients to any Nereus server in the world which allows you access. For example if you put this link "http://nereus.ox.ac.uk/nereus/Nereus/jnlp" on a web page anyone who clicks it will contribute to Oxford University's Nereus cloud.
If I install a server do I have to install clients?
You don't have to, as anyone who visits your server's homepage with their web browser will be able to click a link and join your Nereus cloud. However if you find not enough people do this, or people don't keep their clients open long enough to be effective, then you can deploy Nereus clients to machines you manage as permanently running Windows services/UNIX daemons.
What Firewall changes do I need?
None for clients. If your client machines can browse to your Nereus Server with their web browser, then Nereus will work seamlessly. Nereus uses the http protocol for all communication, and clients only do outbound TCP networking. Ideally a Nereus server should be visible on port 80 on the internet, but this is not essential if you want to install an internal Nereus desktop cloud.
Does a Nereus client interfere with the User?
Nereus runs all processing threads at minimum priority, plus has a sensitive load detector which stops Nereus processing whenever the computer becomes busy with other tasks. So, although no extra software can be entirely undetectable, Nereus has been extensively tested and does not cause undue interference. The one exception is when the computer has a small amount of memory (RAM), so we recommend using Nereus on machines with 1GB or more.
Shouldn't I turn computers off when idle to save electricity?
Whether you want to should not influence your choice of using Nereus. Nereus is designed to work alongside typical computer use (e.g. word processing, email, web browsing) as there is still plenty of idle CPU time available. You will, of course, get more processing from the Nereus cloud if you leave machines on.
What does Nereus cost to use?
There's no cost for the software, but running the computer at full speed instead of idle does consume extra electricity. For a modern PC (less than 2 years old) the typical power increase is about 20% more than when idle. This makes running Nereus on a single PC a few pence/cents per day - about 10 times cheaper than paying for CPU time on datacentre cloud servers.
Do I need a special machine to run a Nereus server?
Not really. The Nereus server software has been tested on typical desktop PC hardware and can support 1000 or more clients simultaneously. We recommend a dual core CPU with 2GB Ram, but as Nereus is Java based you can easily choose Windows or Linux as your preferred operating system. We've also used Amazon EC2 to run a Nereus Server when we needed to get going with a new installation in a matter of minutes.
What is the network load of Nereus?
Nereus works best when there is a good quality network between the server and its clients. Typically one server per organisation servicing all clients on the local intranet is a good measure - except for many thousands of clients where load balancing might be appropriate. The network bandwidth of a basic Nereus install is not significant, but it will mainly depend on what Nereus is being used for. Please contact us for advice on specific issues.