Byte Level Research sells two very cool looking maps of Internet TLDs (Top-level Domains). The maps show the two-letter country codes (e.g. ‘.ca’, ‘.ru’, ‘.uk’) for the countries of the world, which each code shown on a geographical map over the country it represents. The map also includes an index that maps the country codes to actual country names for handy reference.
I recently heard a fellow student ask a good question: “What exactly does ‘user-centered’ design?” The also asked, “Everything is designed for users so how could something not be user-centered?”
Wow, that is a great question! One of my favorite answers to this question comes from the book “The Psychology of Everyday Things” (P.O.E.T.) by Donald A. Norman. Norman says that user-centered design is “a philosophy based on the needs and interests of the user, with an emphasis on making products usable and understandable.” (ch. 7, p. 188)
Norman further states that
Design should:
- Make it easy to determine what actions are possible at any moment (make use of constraints).
- Make things visible, including the conceptual model of the system.
- Make it easy to evaluate the current state of the system.
- Follow natural mappings between intentions and the required actions; between actions and the resulting effect; and between the information that is visible and the interpretation of the system state.
In other words, make sure that (1) the user can figure out what to do, and (2) the user can tell what is going on.
The Psychology of Everyday Things is available from:
Note: The Psychology of Everyday Things was reprinted under the title The Design of Everyday Things. I am quoting page numbers from the 2004 edition but I believe they are the same regardless of title.
You are probably used to seeing Internet addresses that look like these
http://www.paranoidagnostic.net/category/sysadmin
cloned.milkmen@paranoidagnostic.net
The first is called a URL and is used for web pages, and the second is an email address. While these addresses both look quite different and are used for different purposes they both contain something called a Domain Name (or DNS name). In this case the domain name is “paranoidagnostic.net”.
Domain names are used to organize Internet addresses in an orderly way and to delegate authority for the creation of Internet addresses.
Internet domain names are organized according to a hierarchy. Levels in the hierarchy are denoted by periods in the domain name. When you read a domain name from left to right, the left is the lowest level and the right is the top-most level of the hierarchy. The lower levels are referred to as subdomains of the higher level domains./p>
For example, the DNS name “www.paranoidagnostic.net” shows three levels of the hierarchy:
The top-level domains (TLDs) are very important. There are only a limited number of top-level domains and they are controlled by various authorities around the world. There are generally three types of top-level domains: US-only, country specific, and generic.
US-only TLDs are only available to US institutions and are under tight control. For example, “mil” is only for the US military, “gov” is only for the US government, and “edu” is only for accredited US post-secondary institutions.
Country-specific TLDs have two letter codes that usually (but not always) correspond to international standard two-letter codes for those countries. For example, the TLD for Canada is “ca” and the TLD for the United Kingdom is “uk”.
generic TLDs are usually available to anyone in the world. “com”, “net”, “org”, “biz”, “info” and a growing list of others are in this category.
TLDs are created by the Internet Corporation for Assigned Names and Numbers (ICANN). Regular organizations cannot have TLDs. Individual people or organizations can obtain subdomains of TLDs. ICANN assigns a separate authority to govern each TLD and those authorities set their own rules about who can and cannot have a subdomain.
For example, the “UK” TLD is governed by Nominet. Nominet administers all UK subdomains and sets rules for how they can be named. In the UK TLD commercial organizations are put in a further subdomain of “.co.uk” and educational institutions in “sch.uk”. For example, a phone company in the UK could get a domain of “myphonecompany.co.uk” but not “myphonecompany.uk” or “myphonecompany.sch.uk”. In the UK authority for some domains is delegated to an organization other than Nominet. For example, subdomains of “parliament.uk” have their own system of rules.
Contrast that with the “CA” TLD. “CA” is governed by an organization called the Canadian Internet Registry Authority (CIRA). It does not have a special subdomain for commercial organizations. A phone company in Canada could obtain “myphonecompany.ca” for a domain name. Similar to the UK TLD government subdomains are restricted. Only the Canadian Federal Government can obtain subdomains of “gc.ca”.
Some countries have turned over control of their TLDs to commercial companies that allow anyone in the world to use them. For example “TV”, “FM”, and “AD” are all country-specific TLDs that are administered by commercial organization that treat them like generic TLDs.
It is often very helpful to know who governs a TLD and what their policies are. For example, if you find a website might appear to be for a institution in a specific country and have a subdomain that appears from that country. In the UK and Canada (”.ca”) you could be sure that any site that ends in “.parliament.uk” or “.gc.ca” are associated with the government. But a website in other subdomains may not be authentic. Each country has its own authority and own rules so verifying who is real and who is not can be challenging.
Fortunately, the Internet Assigned Numbers Authority (IANA) keeps a list of all of the TLD authorities. You can find the contact information, usually including website addresses, for every TLD on that list. You can then contact the listed authority to find out what their policies are.
Note: The Internet’s domain name system is referred to as DNS (Domain Name System) and defined by many RFCs (Internet standards).
This is a screencast to go with my last post. It shows some of the screens from the “get it!” service include some of the problem screens.
Unfortunately I could not reproduce all of the problems we talked about last week… so you just get to hear me talk about them. If you have a “get it!” bug that you can reproduce, please post a comment here and describe it. I’d be happy to track it down and post screenshots (and an explanation if its helpful).
Please note that this screencast file is extremely large and may take a while to load (80MB!).
If you have looked for articles in the library’s online databases, you have probably seen some green and white “Get It!” icons. If you have actually clicked one of those buttons you might be left with some questions about how they (may or may not) work. Those buttons are one part of the library’s “citation linking” service and in this article I will explain what that service is, what the “Get It!” buttons do, and how you can use the citation linker ways you might not have known about.
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