Electronic Data Processing Environment

1. Understanding EDP Environment

2. Objectives
• Describe organizational structure of an EDP Environment
• Define computer files
• Explain the purpose of computer files.
• Describe the elements of a file
• List and explain types of files
• Explain file organization methods.
• Explain file Access Methods
• Explain storage media devices.
• Describe processing activities.
• Explain vulnerability of files:
(i) Improper/fraudulent input
(ii) Software/programme abuse
• Master the use of keyboard

3. Data
Data is defined as any collection of facts. Thus,
sales reports, inventory figures, test scores,
customers’ names and addresses, and weather
reports are all examples of data. Note that data
may be numerical (e.g, inventory figures and
test scores) or they may be numerical (e.g. ,
names of students and addresses, drawings).

4. Data Processing
Data processing is the manipulation of data into a more
useful form.
Data processing includes not only numerical calculations
but also operations such as the classification of data and
the transmission of data from one place to another. In
general, we assume that these operations are performed
by some type of machine or computer, although some of
them could also be carried out manually. Data processing
system refers to the equipment or devices and
procedures by which the result is achieved.

5. Types of Data Processing
Modern data processing employing machines
and other devices falls into two basic categories:
• Mechanical Data Processing
• Electronic Data Processing.
Mechanical processing system use a combination of manual procedures and
mechanical equipment. The system uses various devices such as typewriters,
sorters, calculators, collators, tabulators, duplicators, and verifiers.
In electronic data processing different types of input, output, and storage
devices may be interconnected to an electronic computer to process data.

6. Electronic Data Processing
Electronic Data Processing (EDP) can refer to the use of
automated methods to process commercial data. Typically, this
uses relatively simple, repetitive activities to process large
volumes of similar information.
For example: stock updates
applied to an inventory,
banking transactions applied
to account and customer
master files, booking and
ticketing transactions to an
airline's reservation system,
billing for utility services.

7. Organizational Structure of an EDP
Environment
Any job that comes to an
organization is in a form of data.
Requirement analysis has to be
done and the turnaround time
has to be determined. After the
process has been defined then
contract can be entered into with
the client. The data is then
assembled, transferred from the
client and stored on the server.
The job can then be processed,
compared, go through quality
assurance, export in a required
format and then transfer back to
the client

8. Computer Files
• Computer files are files maintained in computer-readable
form.
• A computer file is a resource for storing information,
which is available to a computer program and is usually
based on some kind of durable storage. A file is
"durable" in the sense that it remains available for other
programs to use after the program that created it has
finished executing.
Computer files can be considered as
the modern counterpart of paper
documents which traditionally are
kept in office and library files, and
this is the source of the term.

9. Types of Computer Files
Computers can store information on several
different storage magnetic disks, magnetic tapes
etc. A computer can store millions of bytes of
data or information. so that we can store and
access data easily from the storage device the
operating systems provides us data file system.
.doc, .xls, .png, .jpeg, etc are various extensions
for various files.

10. Some File Types
Batch file Same as command file - contains operating system commands.
Binary file Contains data or instructions in binary format.
Command file Contains operating system commands. It is a text file.
Data file Contains data
Directory file Contains bookkeeping information about files that are below it
Executable file Contains a program or commands in a format executable by a computer
Library file Contains functions in object format.
Map file Contains a map of a program
Object file Contains code that has been compiled
Text file Contains textual data (that is, data that can be read by humans), including files
you create with a text editor and any file in ASCII format.
Word
processor
Wp, text, rrf etc
Print or view Ps, dvi, gif
Archive Related files grouped into one file, sometimes compressed, for archiving or storage

11. File Types & Extension
Extensions are three letters or numbers that appear at the end of a file
name and indicate what type of file it is. What the file is used for. And if it
will work on your computer.
CAD exchange files .dxf
Drawing Web Format .dwf
Animations, audio & video
GIF animations .gif
Sound files .wav, .au, .aif, .mid
Video files .mov, .mpeg

12. File Type Extension
Text
ASCII .txt, .asc
HTML files .html, .htm, .shtml, .dhtml
RTF files .rtf
Binary word processing files .doc, .wri
Images
Photoshop native format .psd, .pdd
GIF compressed .gif
JPEG compressed .jpg, .jpeg, .jpe, .jfif
TIFF image .tif, .tiff
Picture format .pic, .pct, .pict
Portable Net Graphic .png
CAD

13. File Organization Method
File organization is a way of organizing the data
or records in a file. It does not refer to how files
are organized in folders, but how the contents
of a file are added and accessed. There are
several types of file organization, the most
common of them are:
•Sequential
•Relative
•Indexed.

14. Method of File Organization
• Sequential,
• Line-sequential,
• Indexed-sequential,
• Inverted list
• Direct or Hashed Access

15. Sequential Organization
A sequential file contains records organized in
the order they were entered. The order of the
records is fixed. The records are stored and
sorted in physical, contiguous blocks within each
block the records are in sequence.
Records in these files can only be read or
written sequentially.

16. Line-Sequential Organization
Line-sequential files are like sequential files, except
that the records can contain only characters as
data. Line-sequential files are maintained by the
native byte stream files of the operating system.
In the COBOL environment, line-sequential files
that are created with WRITE statements with the
ADVANCING phrase can be directed to a printer as
well as to a disk.

17. Indexed-sequential Organization
Key searches are improved by this system too.
The single-level indexing structure is the
simplest one where a file, whose records are
pairs, contains a key pointer. This pointer is the
position in the data file of the record with the
given key. A subset of the records, which are
evenly spaced along the data file, is indexed, in
order to mark intervals of data records.

18. Inverted List
In file organization, this is a file that is indexed
on many of the attributes of the data itself. The
inverted list method has a single index for each
key type. The records are not necessarily stored
in a sequence. They are placed in the are data
storage area, but indexes are updated for the
record keys and location.

19. Direct or Hashed Access
With direct or hashed access a portion of disk
space is reserved and a "hashing" algorithm
computes the record address. So there is additional
space required for this kind of file in the store.
Records are placed randomly through out the file.
Records are accessed by addresses that specify
their disc location. Also, this type of file
organization requires a disk storage rather than
tape. It has an excellent search retrieval
performance, but care must be taken to maintain
the indexes.

20. Access Methods
• Access method is a program or a hardware mechanism
that moves data between the computer and an
outlying device such as a hard disk (or other form of
storage) or a display terminal.
• There are two type of access method
 Random Access: you can jump directly to point Z. Disks
are random access media
 Sequential Access: you must pass through all
intervening points to go from A-Z. Tapes are sequential
access media.

21. Storage Media Devices
Storage Media Device is any hardware device capable of holding information.
Types of computer storage
• Floppy diskette
• CD-ROM disc
• CD-R and CD-RW disc
• Cloud storage
• DVD-R, DVD+R, DVD-RW, and DVD+RW disc
• Jump drive and USB flash drive
• Hard drive
• Memory card
• Memory stick
• Tape cassette
• Zip diskette

22. Processing Activities
• Assignment
• Class Discussion

23. Vulnerability of Files
Vulnerability of files is a weakness which allows an
attacker to reduce computer files assurance.
(i)Improper/fraudulent input: is a type of
vulnerability in computer software that may be
used for security exploits.
(ii)Software/program abuse: this is a situation
whereby the vulnerability of a software/program is
taken advantage of in order to make it behave in
an unintended or unanticipated way. The piece of
software hackers use to abuse software is called
exploit.