About the PPS Web Pages
On any page without the "navigation bars", clicking on the small logo
(or text, if you have loaded the text-only version of this
page) in the top left
corner gets you back to
the Main Index.
When producing these Web pages the idea has been to avoid using too many fancy
images in order to minimize the time it takes to load them. However I thought
it was worth including a few in-line images to try make the pages look smart.
But see below.
Naturally, with a subject like protein structure, images are an absolutely
integral part of the course material, so the above doesnt apply to those
pages. Some of the images in the course are quite large (some very) but many
of these are "iconized" and we will give an indication of how just how large
these are to give you due warning.
Setting your Web-browser so that it ignores images
This is very easily done- for example with Netscape, make sure Auto Load
Images (under Options) is not selected. If you are using Mosaic,
select Delay Image Loading (under Options). The result is that
when any WWW page is loaded, the position of any image is shown (along with its
substitute text if provided) without the image itself being displayed.
The Text-only Pages
Having said that, I also considered it worth providing text-only pages,
generated automatically. Again, this only applies to the main and sub-index
pages of the course hypertree- not to the course material.
Here is the text-only version of the
WWW Browsers and Cached Files
When you view WWW pages, the browser stores a local copy of the HTML documents
and their associated images and other files; i.e. caches them so they
don't have to be downloaded from a remote site again the next time you want to
access them. The size of these local caches are limited (by options you set on
your browser); they therefore generally store the most recently accessed files.
The drawback is that you retain old copies of these cached files- this is a
problem when repeatedly accessing a site whose pages are continually being
changed- such as the PPS pages.
To overcome this problem, you can force your browser to download a file from its
site of origin, instead of using a cached copy- i.e. by pressing the
Reload button on Netscape or Mosaic. The course e-mail
archives are constantly changing (they are
updated every hour at Birkbeck, and every day at the mirror sites), so we
recommend that you reload these pages each time you look at them.
You probably have a fixed limit to the disk space you can use and perhaps also to the
number of files that you can store on your local system. Its possible for this
limit to be reached as a result of files cached by your web-browser, even
though the size of the cache itself is less than the amount defined in the
options set on the browser. As a result the browser does not report that it
can't cache any more files, and it may do strange things such as stubbornly
refusing to download the latest version of a file, no matter how many times you
press the Reload button. Instead, it carries on displaying an older cached copy.
It can be difficult to realize that you are actually
in this situation, so this is something to be aware of. The solution is to
empty your disk cache (this is under Network Preferences under
Options on the latest
Netscape), and to ensure you do this periodically before your quota is reached
Another problem to be
aware of, relating to caches and proxy servers.
Last updated 21st Jan '96