[10821] in Public-Access_Computer_Systems_Forum
November Ask Dr. Internet Part I
daemon@ATHENA.MIT.EDU (Public-Access Computer Systems For)
Fri Nov 15 21:09:09 1996
Date: Fri, 15 Nov 1996 17:01:46 -0600 (CST)
From: Public-Access Computer Systems Forum <LIBPACS@UHUPVM1.UH.EDU>
To: Multiple recipients of list PACS-L <PACS-L@UHUPVM1.UH.EDU>
Reply-To: Public-Access Computer Systems Forum <PACS-L@UHUPVM1.UH.EDU>
From: "Michael S. Hart" <hart@prairienet.org>
Subject: November "Ask Dr. Internet
This is "Ask Dr. Internet" for November, 1996
Responding to the questions we received from October 15 to November 14
Comments:
We just got a card from WIRED that read:
"When the Digital Revolution rolls over you,
you're either part of the steamroller
or you're part of the road."
Gee. . .I wonder where they got that from?
You might be able to read something about us in the Wall St. Journal
next Thursday in section two, or so we have been told. Of course we
cannot guarantee what they will say, if anything. The Wired article
may have been pushed back to six weeks from now.
Q0.
Cookies.
Because there have been SO many questions about cookie we have larger
than usual answers. . .skip this section if your browser has not been
asking your for cookies.
Q1.
Pierre Salinger and the TWA Flight #800 Crash.
Q2.
More About The Internet Around The World.
Q3.
I Heard The British Were Trying To Buy The Internet.
Q4.
I Heard That You Won't Be Able To Buy Software Anymore,
Only Rent It.
Q5.
How Is The Internet Growing?
Q6.
Why Is It So Much Cheaper To Buy A Whole New Computer,
Than To Upgrade It Piece By Piece?
Q7.
Why Is The US Government Classifying My New Cable Modem Hookup
As "Munitions"?
Q8.
What Have You Heard About A New 500Mhz CPU Chip
Q9.
What Have You Heard About This New Treaty That Will Make It Illegal To
Compile And Publish Statistics, And Apparently Many Other Facts.
Q10.
Book Review and Interview
"Holy Fire" by Bruce Sterling
*****
Q0.
Cookies
A0.
This First Part Is Perhaps Best Considered as Cookie Propaganda
A cookie is an unique piece of information generated on-the-air and sent
to you from up-to-date WWW servers that identifies your request of a
particular Web page.
That cookie might be then used by the server to recognize you just AS YOU
when you will re-contact it later.
This could bee useful for purposes such as a commerce-on-line service to
let the server track your orders just as YOURS, while others are
visiting the same cyberstore and each one receives his own and unique
cookie.
The cookie is a small, inoffensive text file saved in your browser's
directory or folder and stored in RAM while your browser is running. Most of
the information in a cookie is pretty mundane stuff, but some Web sites use
cookies to store personal preferences, such as items already ordered
or any other kind of preference you could have set meanwhile.
If you want to see what information is stored in your current cookie
file, use a text editor or a word processor to open a file called
cookie.txt or MagicCookie in your browser's folder or directory.
***However, Many People Hate Dealing With Cookies***
***So Much So That Some People Still Consider Cookies As A Virus***
THWARTING COOKIES
For computer users who dislike the idea that Web site operators can track
their repeat visits through "cookie" technology, there are several ways to
block the software from collecting or relaying that information. PrivNet's
Internet Fast Forward < http://www.privnet.com/ > prevents the browser from
sending cookies. The program can also block those annoying little ad
banners, eliminating the time it takes to download them. Anonymizer
< http://www.anonymizer.com/ > functions more as a proxy service -- the
information is not given out unless the user grants permission. "Surfing
feels anonymous, like reading a newspaper," says Anonymizer's creator, "but
it's not. What Netscape needs is a feature saying, `Look, I never want to
see another cookie again.'" (Scientific American Oct 96 p50)
HTTP COOKIES
Preliminary Specification - Use with caution
Cookies are a general mechanism which server side connections (such as CGI
scripts) can use to both store and retrieve information on the client side
f the connection. The addition of a simple, persistent, client-side state
significantly extends the capabilities of Web-based client/server applications.
OVERVIEW
A server, when returning an HTTP object to a client, may also send a piece
of state information which the client will store. Included in that state
object is a description of the range of URLs for which that state is valid.
Any future HTTP requests made by the client which fall in that range will
include a transmittal of the current value of the state object from the
client back to the server. The state object is called a cookie, for no
compelling reason.
This simple mechanism provides a powerful new tool which enables a host of
new types of applications to be written for web-based environments. Shopping
applications can now store information about the currently selected items,
for fee services can send back registration information and free the client
from retyping a user-id on next connection, sites can store per-user
preferences on the client, and have the client supply those preferences
every time that site is connected to.
A cookie is introduced to the client by including a Set-Cookie header as
part of an HTTP response, typically this will be generated by a CGI script.
Syntax of the Set-Cookie HTTP Response Header
This is the format a CGI script would use to add to the HTTP headers a new
piece of data which is to be stored by the client for later retrieval.
Set-Cookie: NAME=VALUE; expires=DATE;
path=PATH; domain=DOMAIN_NAME; secure
NAME=VALUE
This string is a sequence of characters excluding semi-colon, comma and
white space. If there is a need to place such data in the name or value,
some encoding method such as URL style %XX encoding is recommended, though
no encoding is defined or required.
This is the only required attribute on the Set-Cookie header.
expires=DATE
The expires attribute specifies a date string that defines the valid life
time of that cookie. Once the expiration date has been reached, the cookie
will no longer be stored or given out.
The date string is formatted as:
Wdy, DD-Mon-YYYY HH:MM:SS GMT
This is based on RFC 822, RFC 850, RFC 1036, and RFC 1123, with the
variations that the only legal time zone is GMT and the separators between
the elements of the date must be dashes.
expires is an optional attribute. If not specified, the cookie will expire
when the user's session ends.
Note: There is a bug in Netscape Navigator version 1.1 and earlier. Only
cookies whose path attribute is set explicitly to "/" will be properly saved
between sessions if they have an expires attribute.
domain=DOMAIN_NAME
When searching the cookie list for valid cookies, a comparison of the
domain attributes of the cookie is made with the Internet domain name of the
host from which the URL will be fetched. If there is a tail match, then the
cookie will go through path matching to see if it should be sent. "Tail
matching" means that domain attribute is matched against the tail of the
fully qualified domain name of the host. A domain attribute of "acme.com"
would match host names "anvil.acme.com" as well as "shipping.crate.acme.com".
Only hosts within the specified domain can set a cookie for a domain and
domains must have at least two (2) or three (3) periods in them to prevent
domains of the form: ".com", ".edu", and "va.us". Any domain that fails
within one of the seven special top level domains listed below only require
two periods. Any other domain requires at least three. The seven special top
level domains are: "COM", "EDU", "NET", "ORG", "GOV", "MIL", and "INT".
The default value of domain is the host name of the server which generated
the cookie response.
path=PATH
The path attribute is used to specify the subset of URLs in a domain for
which the cookie is valid. If a cookie has already passed domain matching,
then the pathname component of the URL is compared with the path attribute,
and if there is a match, the cookie is considered valid and is sent along
with the URL request. The path "/foo" would match "/foobar" and
/foo/bar.html". The path "/" is the most general path.
If the path is not specified, it as assumed to be the same path as the
document being described by the header which contains the cookie.
secure
If a cookie is marked secure, it will only be transmitted if the
communications channel with the host is a secure one. Currently this means
that secure cookies will only be sent to HTTPS (HTTP over SSL) servers.
If secure is not specified, a cookie is considered safe to be sent in the
clear over unsecured channels.
Syntax of the Cookie HTTP Request Header
When requesting a URL from an HTTP server, the browser will match the URL
against all cookies and if any of them match, a line containing the
name/value pairs of all matching cookies will be included in the HTTP
request. Here is the format of that line:
Cookie: NAME1=OPAQUE_STRING1; NAME2=OPAQUE_STRING2 ...
Here are some sample exchanges which are designed to illustrate the use of
cookies.
First Example transaction sequence:
Client requests a document, and receives in the response:
Set-Cookie: CUSTOMER=WILE_E_COYOTE; path=/; expires=Wednesday, 09-Nov-99
23:12:40 GMT
When client requests a URL in path "/" on this server, it sends:
Cookie: CUSTOMER=WILE_E_COYOTE
Client requests a document, and receives in the response:
Set-Cookie: PART_NUMBER=ROCKET_LAUNCHER_0001; path=/
When client requests a URL in path "/" on this server, it sends:
Cookie: CUSTOMER=WILE_E_COYOTE; PART_NUMBER=ROCKET_LAUNCHER_0001
Client receives:
Set-Cookie: SHIPPING=FEDEX; path=/foo
When client requests a URL in path "/" on this server, it sends:
Cookie: CUSTOMER=WILE_E_COYOTE; PART_NUMBER=ROCKET_LAUNCHER_0001
When client requests a URL in path "/foo" on this server, it sends:
Cookie: CUSTOMER=WILE_E_COYOTE; PART_NUMBER=ROCKET_LAUNCHER_0001;
SHIPPING=FEDEX
For more about cookies, and there is plenty, try:
http://ds.internic.net/rfc/rfc822.txt
http://ds.internic.net/rfc/rfc850.txt
http://www.w3.org/hypertext/WWW/Protocols/rfc1036/rfc1036.html#z6
http://ds1.internic.net/rfc/rfc1123.txt
Q1.
Pierre Salinger and the TWA Flight #800 Crash.
A1.
As most of you who follow the media at all know, a large passenger
plane exploded and went down off Long Island, New York, but we may
not be able to publish the information about it. . .even though it
happened quite a while ago.
What we would tell you is that Pierre Salinger, former White House
Press Secretary, released to the press some information previously
posted on the Internet months ago and still there as of last week,
suggesting that the plane was shot down by the U.S. Navy.
The point of our mentioning this is not that we think this is true
. . .the point is that the information, which had been on the Net,
apparently for months, vanished overnight from those locations, at
least from some, if not all of them.
Therefore, we further encourage you, beyond our normal statements,
which are meant to save bandwidth, to save data locally, do NOT do
what most people do, and leave the data where you found it, with a
presumptive presumption that it will be there when you come back--
a day, or a week, or a month, or a year later.
Megabytes are a dime these days, you waste more of your own valued
time in redownloading information again and again and the truth is
that half of what you look at when browsing is something either in
a site you previously browsed, or that a close friend did.
Example: an efficiency expert once reported that most phone books
are used to look up the same phone numbers over and over and over,
so s/he recommended that you either put a mark beside each number,
as you look it up the first time, to make it easier to find again,
or to write it on the covers of the phone book.
Of course, most people will deny they could benefit from this, but
after trying this for a few years, I was amazed.
So. . .don't be the victim of "Link Rot" and lose your data. . .it
could be something you really want later. [See the three rules of
computing listed at the end of this edition of Ask Dr. Internet.]
Q2.
More About The Internet Around The World.
A2.
Internet World reports that the net is expanding around the world,
with more than 186 countries now reachable with e-mail. Yet 98%
of all computers providing net access and content are in North America,
Europe, Japan, and Australia. The result? "The continents of Africa,
Asia, and South America are tiny islands in cyberspace."
[Credit to Bruce Sterling's novel, Islands in the Net, 1989,
talk about a visionary, most of the people on the Internet now
had never heard of it then; more about Bruce Sterling below.]
Telephone lines and other parts of the technological infrastructure
constitute a major barrier between these islands and the cyber mainland.
Africa, for example, "has the lowest teledensity (phone lines per population)
in the world. The continent has 12 percent of the global population, but
only 2 percent of the world's main telephone connections." Another barrier
is outmoded regulations, such as those in India that keep all telephone
service in the hands of a government monopoly.
Q3.
I Heard The British Were Trying To Buy The Internet.
A3.
"ANOTHER GLOBAL GORILLA": BT TO BUY MCI
British Telecommunications is about to buy MCI Communications for as much as
$21 billion. The combined companies will have an annual revenue of $35
billion and operations in 70 countries. Industry analyst Gary Miller says:
``You really only have had one internationally recognized global player and
that's been AT&T. Now you have another global gorilla.'' MCI will continue
to operate under its present name. (Washington Post 2 Nov 96) [Edupage]
You should also be advised that various organizations are building what they
call "Second Internets". . .some are academic, some commercial, some even in
the governments. . .they all realize now what everyone on the Net realized a
few years ago when it happened, that for the governments, who paid for it in
the first place, to sell the Internet to the phone companies, was a HUGE!!!!
mistake. . .which cost them more in the first year of renting back Net lines
than it would have cost them to keep it running themselves for 6 years. . .!
Q4.
I Heard That You Won't Be Able To Buy Software Anymore,
Only Rent It.
A4.
MEANWHILE, SOFTWARE SHIFTS TOWARD SUBSCRIPTION MODEL [Edupage]
Microsoft has sold its software packaging operation and is planning to
distribute most of its Windows upgrades over the Internet, says the
company's CFO: "We are starting to evolve our revenue model to
subscriptions." The major barrier to adopting that strategy whole-heartedly
right now is the lengthy download times it can take users to upgrade their
favorite software. The next version of Windows (97 or 98, depending on
release date) will definitely be shipped in shrink-wrapped boxes, say
company officials, but beyond that, they're hoping that the flexibility of
the Internet will allow them to offer more of a cafeteria-plan type approach
to incremental enhancements. (Investor's Business Daily 31 Oct 96 A6)
This sort of thing has been tried before, without success, when companies
tried to prevent you from selling a program you had only "licensed", on a
presumption that you didn't "own" the program, only were "licensing" it--
the courts declined to uphold this view.
However, if you never even get anything physical. . .and the really biggy
players get behind it, you may never own anything ever again.
Q5
How Is The Internet Growing?
We will give a more detailed report on this in our annual January report,
but here is something for now. Remember this report is only for the US.
SURGE IN ONLINE USERS PREDICTED
A new study by Inteco Corp. predicts that 13.5 million new households will
sign up for online services within the next year, with 42% of those
households still needing to buy their first computer. The poll of 2,660
households also yielded a surprise finding -- online usage among households
with income above $25,000 has declined, from 9.8 million earlier five
months ago, to 8.7 million now. The total number of online households in
the U.S. is pegged at 15.2 million. (Investor's Business Daily 4 Nov 96 A6)
This is out of over 100 million people online in the world. There are
different statistics for households versus individuals, so be careful.
