Speed up your Classroom Internet Access by 100 Times!
For less than $1000
How? …. Read on.
Most schools now have some form of internet access router. Some use Wingate, others use
Linux, Netscape Proxy, Microsoft Proxy, or one of the other less well known proxy servers.
The common feature amongst all of them is that they allow many users to connect to the
Internet via one phone line. All of them act as "intermediate buffer" between
the users and the Internet itself. Proxy Servers act on behalf of the Internet –
hence the name "proxy". Some Internet Service Providers (ISP) also use a proxy.
When you think you are accessing the "Internet", you are often accessing the
proxy on their computer. The ISP pays less for their data downloads and you get
information quicker – everybody is happy.
Cache – What Cache? (pronounced ‘kaysh’, or
‘cash’ – I prefer ‘kaysh’.)
According to the Oxford …. A cache is "…a hiding place for treasure".
A treasure it certainly is!! The key to survival in the Internet classroom is the proper
handing of caching. You MUST know what your computer is doing with its "hidden
treasures" and how to make it do what you want.
In Internet jargon, a "cache" has two locations. One is in the RAM and the other
is an area on the hard disk where files are stored. Each time your browser accesses a site
it downloads and caches all the text and graphics associated with the site. Every picture,
every animation, every typed word!! No wonder some sites take ages to "open".
The developers of browser software (like Netscape Navigator and Microsoft Internet
Explorer) thoughtfully included this feature so that if you decide to return to a
previously viewed page it will read off the memory (RAM) cache, or the hard disk cache,
rather than downloading all the files again.
The caching feature of browsers is the secret to FAST Internet access in the classroom.
Your ISP has a big one Too!
Yes your ISP uses a cache as well. In most cases when you think you are accessing the
"Internet", you are actually just reading files off your ISP’s hard disk
cache. Chances are your ISP’s cache runs into Gigabytes!! They have to pay for
downloads from THEIR provider, so anything they can send to you directly from their cache
costs them nothing (apart from the original down load into their cache). In effect, the
"Internet" can be thought of as a great big network of caches. You can never
really be sure whether you are "live" or reading off a cache.
Your Proxy’s Cache?
Yes, your proxy Server ALSO has a cache. It actually gets quite complex …
The Sequence of Caching …
When you access a page, a copy of the files is stored in memory (your computer’s
RAM). A copy is also stored in your computer’s hard disk cache. A copy is also stored
in your Proxy’s cache (Wingate, Linux, Netscape Proxy Server, Microsoft Proxy Server,
etc). A copy is also stored in your ISP’s cache.
Now the $1000 secrets …..
Instant …
If you want INSTANT Internet access for students in your class, before the lesson go
around to EACH computer in the room and access ALL the pages your students will be
accessing during the lesson. Don’t close the browser and certainly don’t turn
the machines off. Either of these actions will lose the cached pages from memory. This may
seem very time consuming, but you wanted "instant"!!!
Not instant, but almost …
Do as above, but you CAN turn the machines off between accessing the pages and the lesson.
It doesn’t matter how long between your caching session and when the students use the
browser. The files will be stored on hard disk. Access won’t be instant, but it will
be FAST.
Fast, but not as fast as the last one …
Use ANY computer on the network (except the one with the proxy server on it) to access
each of the pages your class will visit. Your proxy server will make a cached copy on its
hard disk so that when students access the pages it will be downloaded from the proxy
server, rather than your ISP.
NOTE: The browser on your proxy server system has its own cache and probably
doesn’t go through the proxy server to access the Internet (Wingate doesn’t, for
example). If you want to cache for others on the network, you can NOT use the browser on
your proxy server computer.
The best you can expect …
If you don’t adopt one of the above strategies, the best you can expect is 20, or 30
users battling to share one phone line. Each page will take thirty times longer than it
would take using a stand alone!! Forget about your lesson.
Lesson Management
1. Divide and Conquer …
It is not wise to go into an "Internet Lesson" expecting the Internet to work.
It is not wise to go into an "Internet Lesson" expecting the Internet to work.
(Repeated just in case you didn’t notice the first time.)
Plan on using the Internet as PART of the lesson. Perhaps with several activity sheets,
only one of which requires access to the Internet. If the Internet is available, great! If
not, go on with your other activities.
2. Search en Mass, Lament alone …
Everything I’ve said about caching in the previous pages means NOTHING when
"searching". A search is a live action to the Internet. You don’t actually
search all the computers on the Internet itself (all 40 million of them!), but you do have
a direct connection to one of the large computers (probably in the USA) controlling the
data search. Any student performing a search will take priority and restrict access by all
the rest of the class. If you allow a large number of students to search while others are
trying to browse, you’ve had it!! Pack up and go to the library while the computers
slowly unlock.
If you really want to search with a large group, use the multiple activity approach –
Divide and Conquer and survive!
3. Plan and Control …
Provide students with specific URLs and links to access. Warn them not to click randomly
around the pages, or everything will slow down.
The best approach is to make a screen dump of the actual page (using the "Print
Screen" key) and provide students with sheets highlighting where they can go. - You
will, of course, have pre-cached all the pages for faster access.
Copyright, What Copyright?
One solution suggested for speeding things up is to use "web-wacking" software
that downloads entire sites and stores them on your hard disk where they can be easily and
quickly accessed across your Local Area Network (LAN). It’s a grey area of copyright,
but the intention is to make it illegal in Australia. The best advice is don’t.
That was Easy. You can also fine-tune your browser to speed things up
considerably.
Read on for the rest of your $1000 worth …
To Update, or Not to Update?
When you click on a link that has already been cached, the question is whether the cached
copy is current? You may have cached it months ago.
Your browser will communicate with the site to verify that the link is still valid, but
having done that, the question remains – should it display a cached version, or
download directly from the site? - Having read through the notes above about caching, you
are aware that it probably wouldn’t download directly from the site anyway. As far as
the browser was concerned, it would probably download from the nearest external cache (ie
the proxy server in your school)
NOTE: You can actually FORCE a download from the original site using a key combination
with the "Reload/Refresh button in the browser.
All browsers allow you to set "Verification" periods. In Netscape Navigator the
choice is: "Once per session", Every time", or "Never". In
Internet Explorer the choice is: "Every visit to the page", "Every time you
start Internet Explorer" and "Never". With all the different browsers and
versions, I won’t go into the details of how to change these settings. Drop me an
email if you can’t work it out.
$500 worth …
This is one of the key tricks to speeding things up. Select "Never" as
outlined above. This doesn’t mean the page will ‘never’ be loaded, it just
means that IF a copy exists in the local hard disk cache, the browser will load it and
‘never’ look for a more recent version. It won’t even look at your proxy
server’s cache! VERY FAST access.
If the page doesn’t exist in the hard disk cache the browser will follow the normal
process and start searching external caches.
As long as you leave at least one of your systems set to "Once per session", you
will ensure that the proxy server cache remains current and you can easily change the
settings on individual systems if you need to.
NOTE: Some pages have imbedded code that forces an update each time it is accessed.
Unfortunately there is nothing you can do to overcome this problem. Maybe if we all
boycott this type of page they will get the hint.
Well that’s about it. If you know of any other tricks, drop me a line. Just one last
word of caution … You can spend a lot of money on hardware and cabling attempting to
speed things up. You will get a more dramatic increase in classroom access if you adopt
the strategies outlined above.
The "Less than $1000" title?
It WILL cost you less than $1000 to speed things up by factors of ten!!! It will cost you
nothing, but would you have read this far if it was free?? If you really want to throw
away the money mail it to me in small bills.
Good Luck.
Jim Fuller
PS. I don’t claim to be an expert. If there are errors, or omissions please let me
know.
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