• Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint

7.3. Unix

Any Unix workstation can run a web client, but it is probably overkill to dedicate workstation hardware to web browsing when Macintosh or PC hardware will do just fine. Linux is the most popular version of Unix[1] for commodity PC hardware, partly because it is free along with all of the source code. Given identical PC hardware, you can get much better performance from Linux than from Windows, but until recently there has been little commercial software available for Linux because of its origins in the hobby world. Linux does have sufficient software to be a good web client because there is Netscape for Linux and a good Java Virtual Machine as well as all the usual Unix tools that make it relatively easy to figure out exactly what's going on in the system and the network: top, vmstat, strace, traceroute, ping, etc. Linux is a boon for anyone interested in operating systems. Here are a few of the things you can do to figure out exactly what is going on in your Linux web client:

[1] Though Linux is not Unix in a legal sense.

  • Start top and use M to sort all processes by memory usage. Leave it running. You'll probably see that Netscape is your single largest process and that it keeps growing as you use more of its features.

  • Leave netstat -c running and you can see Netscape open connections as you retrieve web pages. Connections are open when netstat says they are in the ESTABLISHED state. The connections should all eventually be closed, except perhaps for connections such as the one to your POP mail server that polls for new mail.

  • You can run Netscape with the strace command to see all system calls as they are made and understand a bit more of what Netscape is doing. Netscape's performance will probably be unbearably slow while you're tracing it, but it is instructive. You can also get the Netscape source code from http://www.mozilla.org/, if you want to try to modify the code to improve the browser's performance yourself.

  • You can use ping to see what the latency to any given web server is. Most web servers are configured to respond to ping. If you ping yourself and the latency is significantly over 1 ms, this indicates that you have a poor implementation of IP. Pinging a web server on the same LAN should have a latency under 10 ms. If not, you may have an overloaded LAN or a very poor implementation of IP. If you're pinging a web server across the Internet, anything under 50 ms is good, but latency up to 200 ms is quite normal. When latency gets close to 1 second, you have a poor connection to that server. The trace-route command can tell you at exactly which router things start to slow down. This is useful for detecting the quality of an ISP.


PREVIEW

                                                                          

Not a subscriber?

Start A Free Trial


  
  • Creative Edge
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint