Ch. 8 Key Concepts

Ch. 8 Key Concepts
Web Server Hardware and Software

· Dynamic Page-a web page who’s content is shaped by a program in response to user requests.
· Static Page-an unchanging page retrieved from a disk.
· Dynamic Content-is nonstatic information constructed in response to a web client’s request.
· Server-any computer used to provide (or “serve”) files or make programs available to other computers connected to it through a network such as a LAN or a WAN.
· Server Software-the software that a server computer uses to make server files and programs available to other computers.
· Database Server-the server computer on which database management software runs.
· Request Message-the message that a Web client sends to request a file or files from a Web server. A typical request message from a client to a server consists of 3 major parts (HBL).
o Request Line-contains a command, the name of the target resource, and the protocol name and version number.
o Optional Request Headers-can contain information about the types of files that the client will accept in response to this request.
o Optional Entity Body-sometimes used to pass bulk information to the server.

Electronic Mail (E-mail):
· Benefits-quickly transfers information within seconds; can send all sorts of different documents such as word, pictures, movies, worksheets, etc.
· Drawbacks-the amount of time business people spend replying to email


· Virus-a program that attaches itself to another program and can cause damage when the host program is activated.
· Black List Spam Filter-a list that looks for “From” addresses in incoming messages that are known to be spammers.
· White List Spam Filter-examines “From” addresses and compares them to a list of known good sender addresses.
· Packet Internet Groper (PING)-tests the connectivity between two computers connected to the internet.
· File Transfer Protocol (FTP)-is part of the TCP/IP rules that defines the formats used to transfer files between TCP/IP-connected computers.
· Full Privilege Protocol (FTP)-it’s an FTP connection to a computer on which the user has an account.
· Anonymous FTP-allows the user to log on as a guest.
· Link Checker-examines each page on the site and reports any URL’s that are broken, seem broken, or are in some way incorrect.
· Orphan File-is a file on the Web site that is not linked to any page.
· Dead Link-when clicked, displays an error message rather than a Web page.
· Reverse Link Checker-checks on sites with which a company has entered a link exchange program and ensures that link exchange partners are fulfilling their obligation to include a link back to the company’s web site.
· Blade Server-a recent innovation in server computer design is to put small server computers on a single computer board and then install many of those boards into a rack mounted frame.
· Virtual Server or Virtual Host-is a feature that maintains more than one server on one machine.
· Throughput-is the number of HTTP requests that a particular hardware and software combination can process in a unit of time.
· Response Time-is the amount of time a server requires to process one request.
· Server Architectures-the different ways that servers can be connected to each other and to related hardware, such as routers and switches.
· Server Farms-large collections of servers; called farms because servers are often lined up in large rooms, row after row, like crops in a field.
· Centralized Architecture-uses a few very large and fast computers
· Distributed/Decentralized Architecture-using large numbers of less powerful computers and dividing the workload amongst them.
· Load Balancing Switch-is a piece of network hardware that monitors the workloads of servers attached to it and assigns incoming Web traffic to the server that has the most available capacity at that instant in time.