UNIX System Administration Handbook - Evi Nemeth [415]
To work around these limitations, some pull servers track the groups that users read and prefetch articles for those groups as they arrive. Unfortunately, this scheme can lead to a very large number of groups being tracked, defeating the purpose of a pull feed in the first place.
A third option is a hybrid approach in which the server receives a normal feed that includes the article headers but not the bodies.8
Since the headers are relatively small, this plan does not consume much bandwidth or disk space. Only when a user asks to read an article is it pulled from the upstream server. Because the headers are preloaded onto the local system, the server can quickly present the user with the subject lines and other information for all available articles.
Usenet software
If you want to provide news services in-house rather than pay for an outsourced provider, you will need to find an upstream feed, install software to manage the article tree on your system, and dedicate system administration time to manage and maintain the system.9
Before making any elaborate plans, first ask whether your ISP offers an upstream feed. Even if your ISP is willing to consider providing a feed, you may have to pay extra to receive it.
Next, you will have to track down a news management software package. Table 22.5 lists the popular packages and their fortes.
Table 22.5 Usenet software
Whither Usenet news?
It’s hard to say where Usenet is headed. The percentage of Internet users who post articles has decreased dramatically since the advent of the Web, but at the same time the overall volume of news has increased many times over. Some old timers claim that the signal-to-noise ratio on Usenet today is so low that the system should be abandoned. Meanwhile, new Ph.D. candidates are rushing to write their theses on what a wonderful world-wide community Usenet fosters. As the saying goes, one person’s trash is another person’s treasure.
2. The Apache group was formed by several people who provided patch files for NCSA httpd, a popular web server in the “early days,” circa 1993. The end result was “a patchy” server. Giddit?
3. Why “Squid”? According to the FAQ, “all the good names were taken.”
4. On some systems, you must run mkpasswd or pwd_mkdb after modifying the password file.
5. This is a little white lie. Due to the huge volume of news today, most well-connected sites get a feed from at least one of the major network providers (Sprint, WorldCom, AT&T, etc.). These large sites act as de facto distribution points and virtually guarantee the efficient propagation of articles.
6. It is amazing how many different ways “binaries” can be misspelled.
7. The bulk of the news (~97%) is in the “alt” hierarchy, mostly in the “alt.binaries” groups (92%).
8. Header information includes the author, subject, date, message ID, and threading data.
9. News can require a substantial amount of administration time, possibly as high as .25 to .75 FTEs for a site that receives a full traditional feed. Outsourcing usually looks a lot more attractive in this case.
SECTION THREE:
BUNCH O’ STUFF
23 Printing
When we wrote the first edition of this book, the most common printers were ASCII line printers. Laser printers were new, expensive, and rare. High-resolution output devices required custom driver software and formatting programs.
By the time the second edition was published, line printers had practically become antiques. Numerous standards had been established for page description and printing languages. Laser printers had permeated the market and were widely used.
Today, as we prepare this third edition for publication, laser printers often connect to an Ethernet network instead of a serial or parallel port. They have largely lost the low-end market to inkjet printers.
With all of these changes in technology, you might expect that the UNIX printing systems