Can any one explain About preparatory at IIT?

Preparatory Course in IIT is good  or bad??

Hello,
There exists (much debated) reservation system for admissions in IITs Hence the reserved seats for SC, ST and PwD can not be offered to a candidate of different category.
But such students fail to qualify JEE Adv for some or other reasons. Hence these seats remain vacant. For these vacant seats, students are selected for prepatory courses to prepare them to pursue competitive academic program in IITs.
Preparatory Courses
The vacant seats reserved for SC, ST and PwD candidates are allotted to the candidates of respective categories for admission to a preparatory course of one-year duration on the basis of relaxed admission criteria .
Admission is given to the candidates in the preparatory course provided
(i) the seats reserved for the respective category are vacant,
(ii) candidates have not accepted a seat in the preparatory course earlier.
All the IITs run preparatory courses of one year duration for SC, ST and PwD candidates intended to prepare them to pursue the academic program to which they have been allocated. At the end of this course, candidates are declared as pass or fail.
On successful completion of the course, the candidates are offered direct admission next year to the already allotted undergraduate course.
Candidates admitted to the preparatory course are also eligible to appear in next JEE (Advanced) subject to fulfilling other eligibility criteria.
I hope this would help you. For further queries please feel free to write me down in the comment box.