General principles

1 - Essential and ancillary tasks

A task represents works in the project and has a non-zero duration.

We often find in a project tasks to realize on a priority basis, and other tasks either distributed throughout the project (project management, support) or to execute if there is time available ... With traditional project management software that put all the tasks at the same level, these non-priority tasks are likely to appear as the critical path, and to have a proper schedule you will ignore them or cheat on their data .. . This can lead to forget work, misjudge the charges ...

This is why I have provided two types of tasks: the essential tasks that are only taken into account in calculating margins and critical path, the end of these tasks is the essential end of the project, and other tasks called ancillary which are not taken into account in margin calculations. This causes that an essential task can not be dependent on an ancillary task.

2 - Events

Unlike tasks events have not work to do and have no time. They may represent steps of the project, objective dates that we want to show in the schedule, or be intermediates in the definition of links between tasks.

There may be links between tasks and events and for that I have provided two types of events: the essential whose may depend essential tasks, and ancillary.

Events do not represent work and are therefore transparent in the margin calculations, their possible displacements are not taken into account. However if they were set a fixed date and hour, margins are calculated not to move this fixed date and hour.

3 – Decomposition in levels and groups of tasks

When a project exceeds a few dozen tasks, it is recommended to do a tree with several levels, and for this tools are available such as the Work Breakdown Structure (WBS).

Planning of such project raises philosophical problems depending on whether we favor top-down or bottom up, and we prefer distribute or consolidate margins.

This program is not aimed at large projects, the task decomposition in levels has not been retained.

However to facilitate entering and presenting data, we can define tasks groups or groups. They are tasks or events grouping (only one level is allowed, a group cannot contain groups).

A group has a beginning, and all tasks or events of the group must begin after this beginning. A group ends when all its member tasks are ended and all its events were reached.

A group can be defined as essential or ancillary. An essential group can only contain essential members, and an ancillary group can only contain ancillary members.

4 - Links

The most commonly used links are links from the beginning of a task after the end of a task known predecessor, possibly with a delay. The program allows to have for a task, a group or an event as many links of this type that we want with predecessors task, group or event.

When you create a link to group end, it is equivalent to create a link to the end of each member of the group (and with the group beginning if it has not yet members).

However there are limitations in the choice of predecessors: an essential task, group or event can not have non essential predecessors, and a task, group or event can not have a predecessor who has it already among its predecessors (else the graph has loops and the calculation would become impossible). To facilitate the definition of links the program will provide the list of items (task, group or event) selectable as predecessor, and you will make a selection from this list to define a link

In a link definition we can define a delay in general positive. The program allows to define a delay in a whole number of minutes for each link, and can have positive or negative numbers, which can sometimes be useful.

More, following constraint type, this delay may be specified as worked time or elapsed time.

To simplify the inputs, only one type of link, said begin after end was retained whereas in other programs four types of link are available. But the three other types are uncommon use and their absence should not introduce limitations in the planning.

For links said begin to begin, you can define an event that determines the beginning of the involved tasks. For links said end or end to end after the start, it is undesirable to use them because it introduces constraints on how to achieve the corresponding tasks. It is better to divide the tasks to avoid these constraints.

5 – Durations, delays and horary precision

All durations are entered as hours and parts of hour and saved as a whole number of worked minutes.

Delays are also entered as hours and parts of hour and saved as a whole number of minutes.

Following precision required for horaries, you may choose between following precisions : 1 hour, half an hour, quarter of hour, 10 minutes, 5 minutes, 1 minute. The times, duration and delays will be rounded for displaying, up or down following the case, with the chosen precision, and it will be the step for input counters.

6 - Not Worked days and work horaries

In order to define the calendar dates and times, it must be known if the day will be worked or not worked and work horaries during the project .

The program has planned to define in the preferences days worked and not worked, and work horaries, for all future projects, taken into account when creating the project, and to be able to change these days in each project.

These not worked days are usually Saturday and Sunday, and a number of legal holidays.

To simplify the work of defining the calendar, it was provided a mechanism taking into account holidays. Unfortunately these holidays vary from country to country and even in some countries with different regions or states. This is why it is provided a base that will allow each user to define its non-working days depending on local regulations and customs ..