a. The records in logical file are brought into some sequence as determined
by key in the records.
b. A computer is capable of sorting record into a “nested” sequence.
c. Sorting is done by a “sorting generator”. This is part of the computer’s
software and comprises several sophisticated sorting techniques that are
called into use according to the file and the sort requirements.
d. The need of sorting has dimished in line with the demise of magnetic tape
as backing storage.
2. Merging
- Merging implies that two or more files in the same sequence are combined
into one file.
a. File merging
 Two or more separate files of similar seconds and in
the same sequence are marged together so as to
form one file.
b. Record merging
 The records from two or more “input” files, usually
in the same sequence, are combined one record in
the output file.
3. Matching
a. Two or more input files (generally in the same sequence) are compared
records against record in order to ensure that there is a complete set of
records for each key.
b. Masmatched records are highlighted for subsequent action
4. Summanizing
a. Records with the same key in one file are accumulated together to form
one record in the output file.
b. Summanizing usually applies to a file presorted into a certain sequence and
the resultant file is in the same sequence.
c. Records to be summarized are generally of a similar type.
5. Searching

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- It is sometimes possible to partition a serial files thus reducing the search
time by starting the search at the beginning of a known partition.
- A serial file is normally of a temporary nature awaiting sorting into a
useful sequence.
2. Sequential mode:
- direct access sequential mode normally involves accessing sequential a file
that is stored sequentially.
- sequential mode is often associated with a master file held in a certain
sequence and updated by a transaction file sorted into the same sequence.
3. Indexed_sequential/ selective_sequential mode
- Indexed_sequential is a mode of storage where by records are held
sequentially and accessed selectively.
- Groups of unrequired records are skipped past.
- Indexed sequential files may also be accessed haphazandly.
4. Random modes:
- Each record is stored in a location determind from the second’s key by
means of an add generation algorithm.
- The only erricient way to find a record is to use the algorithm
- Random mode is applicable to master files
 Ads of random modes
 No index is required thus saving storage space
 It is a fast access method because little or no searching is
involved
 Transaction do not need storing, thus saving time
 New records are easily insertly into the random file
provided they are not excessive in number
 Dis
 The main problem with the random mode is in achieving a
uniform spread of records over the storage are allocated to
the file

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- This method a basically similar to self addressing except that the key
required a little processing to turn it into the record’s address
- This leads to either a pricise address
3. Matrix addressing
- In somes case, it is necessary to find the add of a record held within a
multi dimensional matrix of record it’s called matrix addressing.
Question 3. Direct Access Searching?
- Where as addressing determines the location of a record by using
algorithmic methods, searching finds the record by scanning groups of
records, and index, or both.
- ]The simplest method is to examine every record a file until the required
record is found a shortcut is generally desiable.
1. Indexed sequential searching
- A cylinder index is created to hold the highest cylinder’s key
- Associated with each cylinder is a block index holding the highest key in
each block within that cylinder
- When searching for a record’s key in the index
 The cylinder index is examined key_by_key until one is
found that is larger than or equal to the wanted key this
directs the search to the appropriate block index
 The block index a similarly examined and the search
 The block is searched record by record until the wanted
record is found
2. Binary searching( binary chopping )
- The key in the index to be binary search must be in sequence and form a
complete set
- The search starts at the midpoint of the index and then moves half way to
the left or right(down or up) depending upon whether are wanted key is
less than or greater than the midpoint key

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- Binary tree searching is suitable for an unsequenced file
- The search is similar to binary searching in that each key examination
holves the rinaining keys, on average
Chapter 11: INTRODUCTION TO ARTIFICAL INTELLIGENCE.
Question 1. AI?
Atificial Intelligence
It has three braches
1. Expert systems (or knowledge- base system)
- ESs are programs that contain the knowledge of human expert, encoded so
a computer can understand it with encated- knowledge seasoning
machinism, ES can tackle problem that are beyond the seach of
conventionally programmed computers.
2. Natural language systems (everyday native language)
- Natural language systems are programs that understand the native
language of the user, such as E
- The most popular natural language systems are those that act as interfaces
to data bases
3. Simple perception systems (for vision, speed and touch)
- They can interpret visual scenes and decide if object meet inspection

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 Is a system that advises the user without question
 There are no practical areas today in which decission
Question 2. A ES Life Cycle (ESLC)?
- An accepted SDLC for expert systems has yet to be developed
There are 6 phases life cycle in an ES
1. Phase1 – Selection of an Appropriate Problem
- Phase 1 involves finding an appropriate problem for an ES, indentifying an
expert to contribute the expertise
- Establishing a preliminary approach
- Analysing the cost and benefitsPreparing a development plan
2. Phase 2 – Development of a prototype system
- A prototype sys is a small version of an ES designed to test assumptions
about how to encode the facts, the relationships and the knowledge of
experts
- The prototype permits the knowledge engineer to gain the expert’s
commitment and to develop a deeper understanding of the field of
expertise
- Other subtasks in this phase:

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