A Quality Management System is essential to obtain the ISO 9000:2000 certification for the Department of Biomedical Engineering at the National Institute of Rehabilitation. The mentioned system demands to development a quality manual, for this the method of direct sequence was chosen and used. With the quality manual developed will be had control mechanisms and implement actions for continual improvement agree with the international norm.

We present as a practical case the payroll system developed for the Education Plannlng and Culture Offices of the Ministry of Public Education.I t is the old payroll problem, but payment normativlty in the Mexican government and the c h a r a c t e r i s t i c s of the education sector lnvolve greater complexity. Because the system is for employees" payment, i t is Important that any modification to the system be done as soon as possible (not more than a week) and with maximum r e l i a b i l i t y to get the expected resu]ts.With these considerations in mind, one of the principal obJectives at the beginning of the proJect was that documentation must be good enough to permit a programmer to become f a m i l i a r with the system and perform maintenance easily and accurately, even i f he or she was not a member of the t e a m that developed i t . We p r e s e n t t h e g u i d e l i n e s we have f o l l o w e d f o r t h e d e v e l o p m e n t and d o c u m e n t a t i o n of t h e p a y r o l l system f o r the E d u c a t i o n Plann.ing and C u l t u r e O f f i c e s of t h e M i n i s t r y of Public E d u c a t i o n . In our experience, maintenance of a system is the most time-consuming and f r u s t r a t i n g a c t i v i t y of our trade, so we have concentrated from the s t a r t of the design on easying t h i s task. One might Imagine the ideal s i t u a t i o n of a maintainer who thoroughly adopts and absorbs the knowledge, the state of mind and the experiences about a system of the o r i g i n a l d e v e l o p e r . T h i s is o b v i o u s l y i m p o s s i b l e , but in a sense, systems d o c u m e n t a t i o n can be t o u g h t of as a s y s t e m a t i c r e c o r d i n g of t h e s e v e r y i s s u e s , at l e a s t any t h a t the a u t h o r c o n s i d e r e d r e l e v a n t . We acknowledge t h a t our ideas about t h i s problem have been taken from o t h e r s o u r c e s , and we do not p r e t e n d to have i n v e n t e d b o i l i n g w a t e r . T h i s work r e p r es e n t s our e f f o r t s to m a t e r i a l i z e t h e s e i d e a s .We believe that documentation of a system must be good, concise and simple enough f o r a person to become f a m i l i a r with the system, evaluate the impact of any modification, and perform i t with ease.Furthermore, whatever changes are made in the system must be immediately reflected in the documentation.In order to l i v e by t h i s code of f a i t h , we have established f o r ourselves a set of rules f o r document a t i o n , d e s i g n , a n a l y s i s and programming of t h e system. We have developed a s o f t w a r e t o o l f o r the permanent u p d a t i n g of the o n -l i n e d o c u m e n t a t i o n . T h r o u g h o u t t h i s p a p e r , we r e s t i c t the meaning of the word system to the s o f t w a r e component of t h e g e n e r a l meaning of the word, w i t h the f o l l o w i n h i e r a r c h i c a l s t r u c t u r e : -System Subsystems Programs ModulesPermission to copy without fee all or.part of this...