Exam up tonight! Due Thurs. 11:55 p.m.

  • Remember: you get 2 hours!
  • Penalty per word over 150 per essay!

Panko, Chapter 11: Network Applications

Users care about applications. The rest is a black box they don’t want or need to open.

1950s-60s: apps hosted by mainframes that did all the work, dumb terminals connected (usu. via coax-style cable, but some by modem-telephonenetwork-modem). No intergrated circuit CPU until 1971 (Intel! the 4004 4-bit microprocessor); all done by vacuum tubes (when “bugs” in the system meant bugs in the system: moths came to the light emitted!). Slow response time, monochrome text, graphics rare, transmission expensive.

1981: first IBM PC used Intel 8088 8-bit CPU

Client/Server Computing: the terminal does at least some processing. Remember: today’s laptops can run the Space Shuttle. Servers are still faster.

Filtering e-mail out of your server is really important if you’re in one of the industries that regs require to archive all e-mail for seven years! Several apps can help with that process.

E-mail protocols:

  1. SMTP (Simple Mail Transfer Protocol): sender-initiated
  2. POP or IMAP to download; receiver initiates

Separate E-mail Body Standards for all-text, HTML…

NetAdmins need to worry more about viruses, worms, Trojan horses, spam, spyware, etc. Widespread problems; antivirus software is almost universal and generally ineffective

  1. So outsource to Postini! Even if you still maintain your own firewall, two lines of defense are better than one.

Spam is bad:

  1. consumes bandwidth
  2. consumes network staff time
  3. consumes user time
  4. may trigger sexual harassment suit (hostile environment! network admin has responsibility not to let such garbage into the workplace!)
  5. consumes storage space if regs require archiving of all e-mails

E-Commerce: Internet opened to it in 1991 (come on, almost 20 years: we should have it figured out by now! ;-) )

  • started with online catalogs
  • then shopping cart, checkout, payment
  • customer resource management (CRM)
  • links to external systems
  • links to internal systems (accounting, pricing, warehousing, shipment, etc.: go check out eBay!)

Peer-to-Peer Computing:

  • Gehl investigated using this model to distribute user manuals and other docs so they wouldn’t have to upgrade a file server
  • method avoids overload of central server
  • also avoids single point of failure
  • gives end user more freedom
  • uses client capacity better
  • Problem: clients come and go (switched off for night!)
  • Problem: client IP addresses switch!
  • Biggest Problem: sceurity! no central control!
  • grad student at research symposium last week talked about working up a model on using P2P capacity in Mayo Clinic to analyze med data
  • Pure P2P IM has no servers, but finding each other can be a hassle if you restart your computer and get a new IP