The Development Of An Operating System For The Microdata 32/S
George Edward Butler · W&M Publish (College of William & Mary) · 1979
This t h e s i s documents a tim e s h a rin g o p e ra tin g system f o r th e M ic ro d a ta 32/S which s u p p o rts two te r m in a l u s e r s .The o p e ra tin g system su p p o rts m u ltip le com m unicating p r o c e s s e s and p ro v id e s f o r th e management o f memory.The m ajor components o f th e p re v io u s s i n g l e -u s e r system have been m o d ifie d to be c o m p a tib le w ith th e new en v ironm ent.Semaphores a r e used to im plem ent c r i t i c a l s e c t i o n s and to s ig n a l p r o c e s s e s .More e la b o r a t e m essage h a n d lin g r o u ti n e s e x i s t to p e rm it com m unication betw een p r o c e s s e s .Each p ro c e s s h a s i t s own m essage queue fo r r e c e iv in g m essages from o t h e r p r o c e s s e s .Program segm ents and s ta c k s a r e swapped from main memory to the d is k when a p ro c e s s makes a main memory r e q u e s t which c a n n o t be s a t i s f i e d .They a re swapped back i n to main memory only when th ey a re needed.No a tte m p t i s made to swap c o n tr o l b lo c k s , system q u e u e s, or b u f f e r s .