Documentation - Preparing and Generating Process Details

(Note: This is part of the early draft for the documentation of ALExSIM-USAS, to give the basic idea and understanding about ALExSIM-USAS and its components/sections. This draft may go through more updates. Latest update - 31 Jan 2020)

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Process Generation / Setup

In this post, I will describe about one of the sections in ALExSIM-USAS, which is the section called Process Generation/Setup. The figure below shows an example of the section.

Step 1 : Process Generation / Setup 

The purpose of the section is to help the user to prepare the input data table. which will contain the details about the processes that will become the input for the process scheduling simulation. 

The section contains 2 sub sections - Random Data Settings, and Manual Data Settings, which will be described in the section below.

Random Data Settings

Random Data Settings in USAS provides the feature for the user to generate the input data using randomized data (instead of manually entering specific input data). Using this feature, user can automatically generates all the required input data (process' details) based on the generation settings specified by the user. 

The advantages of using this feature include, 

• user is not required to manually enter the input data (process details) for the simulation
• user able to produce variations or multiple set of different process details to be used for practising or experimenting with the simulation

Elements in generation settings

For generating the total number of process(es) and data for the process details (burst time, arrival time, and priority number), user is allowed to modify/set the following values:

• Min (minimum) value - indicates the minimum / lowest random value that can be generated for a particular input.
• Max (maximum) value - indicates the maximum / highest random value that can be generated for a particular input.
• Mean value - indicates the mean value for random generation based on Gaussian or Normal Distribution (the Mean value should lies between the Min and Max values, inclusive). This setting require the user to set the std dev value (see the following). If the std dev value is not set, the Mean will only indicates the Mean of Min and Max.
• Std dev (standard deviation) value - this value indicates the standard deviation from the specified mean value. User must set this value to use the Gaussian or Normal Distribution randomization. 

Using the random value generation 

For example, if the user only wants to randomly generate a value within the range 1 to 10 (let say for the total number of processes), without the concern for how many times any of the values within the range to occur, just set the settings for min=1 and max=10. Let the remaining columns blank. No Gaussian or Normal Distribution will be applied.

But if the user wants to generate a value for the input within the range 1 to 10, where most of the random values will be between 5 to 7, the user needs to set the min=1, max=10, mean=6, and std dev=1. The effects will be that most of the time the user click the Generate random values button,  will produce values between 5 to 7, and only few times other values will occur. 

This applies for all the input data (the process' details). Then, to perform the random value generation, user just need to click the Generate random values button below the settings table.

By default, all the settings are already provided with default values. So the user have options to modify or just simply click the generate button without changing any of the settings. 

Manual Data Settings

If the user doesn't want to use the random values generation (e.g. already have input data or process details), he/she can use the manual value preparation. The following figure shows the section when the tab Manual Data Settings is selected.

Manual Data Settings sub-section

The sub-section provides 2 types of manual input data preparation:

• Create empty data table, or
• Load data from an existing data file (*.ptd - 'process table data')

The first type will help user to create an 'empty' table so that user can enter their own data. (The table is not exactly empty, but contains some repeated default values). For example, user may fills up the table by entering the data that they have from the class exercise or other predetermined data.

Another type of manual data preparation is to load input data or process details for the simulation from an existing data file. This feature will actually allows the user to reload the same input data or process details that have been saved from previous session. The required file is a formatted text file with extension *.ptd. (This will be covered in the documentation about Customizing Process Details).

That's all for this section. In the next post i will explain about the section - Customize Process Details.