Deteriorating performance on network computers? Is 1:1 the answer?
There is a well observed phenomena in school networks. Go out and buy nice new computers for your school and their performance rapidly deteriorates with each passing day/week. A computer bought at the same time and placed in the office performs better longer. Is it the way the kids treat them? ... No.
Its a fact that computers take longer and longer to boot from login the longer they are used on a school network. Some schools have invested heaps in high capacity networks to get round the problem to no avail. It's even worse when computers on wheels (COW's) are used. This is where multiple wireless devices are trolleyed around for use in different school areas. This issue has recently been highlighted by a number of schools, so I approached a tech guru at EIS for an explanation and an answer. The answer is a shock, and it goes something like this:
When a user logs in, their 'profile' is loaded from the server. This profile contains information about the users settings, desktop, cookies, favourites etc. This can run into many Mb's, and can take while to load the first time, so the computer stores it on the local hard drive for convenient access the next time the user logs in to that machine. The problem is that unlike an office, in a school its rarely the same user next time.
When a different user logs-in to the computer it loads that users profile in addition to the original. The computer then has two local profiles. Repeat this many times with many different users (a typical secondary school can have a thousand users or more), and the hard drive builds up a staggering number of bulky locally stored user profiles. The computer always searches the local drive when a user logs in before looking to the server for a users profile. As the profiles pile up on the hard drive it takes longer and longer to search through them before giving up and looking to the server. Once it has decided it isn't stored locally it then loads from the server adding further delay. The result, progressively slower boot up times as the computer gets older. Cure? Now thats the interesting part ...
The loading of a profile from a server takes some time and gets worse the more data the user has stored. For wireless devices login times are worse as the connectivity to the server is slower than cabled computers.
Now apparently it is possible with some clever tweeks to set up the computer so that is clears the profiles when the computer is switched off. This keeps the computer clean of multiple profiles but does mean that they have to be loaded each time, slowing down the login times permanently.
Another tweek runs a script that limits the number of stored profiles to 100 (as soon as a new one is added, an older one is deleted). Again this helps, but the fact still remains that if a user either logs in for the first time or their profile has been deleted, the profile has to be loaded from the server.
RM, as one of the leaders in school technology have encountered this many times and have developed a tool to optimise the process, but its only available with their Connect network tools. From discussing with schools, the most popular remedy is to systematically rebuild each computer at regular intervals (usually every term break). This resets the computer and removes the local profiles. It does mean however that the cycle starts again!
School networks have two constants.
- Each computer has multiple users, and users don't always use the same machine twice, so the problem gets worse, and performance deteriorates.
- Most users login at the same time ... soon after the lesson starts! This stresses the network and the server at critical times.
Networks were designed for commercial use, and have been adapted for schools. Commercial users don't generally all turn up and login at once, and generally stick to the same machine so the problem is not so acute. The number of users who login to a commercial PC is very small, so the local storage of their profile is a bonus as it speeds up subsequent logins by the same user.
So the answer is for every user to have their own personal computer rather then share? Could this be the real driver for 1:1 computing in education? Its an interesting thought!
If there are practial ways this can be overcome, or if you know any tweeks we can experiment with, I know a lot of schools who would like the answer, so leave a comment.