Data Storage, WWW Scavenger Hunt

Tom Kelliher, CS14F

Sept. 26, 1996

Announcements:

• Course materials, including lecture outlines, available at
  keystone.westminster.edu/~kelliher/cs14/cs14.html.

• Bring Word 6 for Windows Essentials next time.

• Tuesday's quiz will cover 3A and 3B.

Data Storage

If you had 3,000 books to store, how would you organize them?

Suppose the books had to be broken up into chapters:

• Should the chapters of a single book be ``close together?''

• Suppose chapters can be added and deleted at will. Can we keep the chapters close together, still?

Hierarchical File Systems

1. Drives: A:, C:, N:, etc. The root directory.

2. Directories (folders, sub-directories). Contents?

3. Files.

Diagram of a hierarchy.

Relative, absolute paths.

Types of Files

Some basic categories:

• Text.

• Binary.

• Data.

• Program.

Naming files: DOS's 8.3 standard.

The shortcomings of 8.3.

Shortcomings of long file names?

Some standard file extensions:

1. BAK --- backup file.

2. BAT --- batch (text program) file.

3. COM, EXE --- binary program files.

4. DOC --- Microsoft Word document.

5. GIF --- A graphics file format.

6. HTM --- WWW page file.

Database Files

Stored in proprietary binary format for compactness, quick access.

Terminology:

1. File ---- contains an entire database.

2. Record --- contains info on one ``entity.''

3. Field --- contains one unit of data about a single entity.

Some file organizations:

1. Sequential (like a tape).

2. Direct (random) (like a disk).

3. Indexed sequential.

Discussion points regarding databases:

1. Inaccurate records (credit records).

2. Database merging.

3. Extensive cataloging of personal data:

   Your name, social security number, current address, previous
   addresses, mother's maiden name, birth date and other personal
   information are now available to anyone with a credit card through a
   new Lexis database called P-Trax. As I am sure you are aware, this
   information could be used to commit credit card fraud or otherwise
   allow someone else to use your identity.
   
   You can have your name and information removed from this list by
   making a telephone request. Call (800) 543-6862, select option 4 and
   then option 3 ("all other questions") and tell the representative
   answering that you wish to remove your name from the P-trax
   database. You may also send a fax to (513) 865-7360, or physical mail
   to LEXIS-NEXIS / P.O. Box 933 / Dayton, Ohio 45401-0933. Sending
   physical mail to confirm your name has been removed is always a good
   idea.
   
   As word of the existence of this database has spread on the net,
   Lexis-Nexis has been inundated with calls, and has set up a special
   set of operators to handle the volume. In addition, Andrew Bleh
   (rhymes with "Play") is a manager responsible for this product, and is
   the person to whom complaints about the service could be directed. He
   can be reached at the above 800 number. Ask for extension
   3385. According to Lexis, the manager responsible is Bill Fister at
   extension 1364.