inforamtion about 8255 interfacing with 8051 microcontrollers

"Are you making something from a book by an author that is too lazy to update to current technology?"

it might not be the book Author's fault - maybe the OP has just found an old book in the library, or a second-hand bookshop, or a skip, or something...

"or are you in school being taught by an instructor that is too lazy to update to current technology?"

If this is purely a (school) exercise in interfacing something to an 8051 (or derivative), then it's probably perfectly worthwhile for the purpose of the exercise.
In this case, the school would presumably provide the necessary materials (datasheets, etc) as handouts, in textbooks, or whatever.
This would seem like a perfectly valid exercise in reading a datasheet & implementing its requirements - just so long as the students understand that it is not an illustration of current practice!

"Are you making something from a book by an author that is too lazy to update to current technology?"

it might not be the book Author's fault - maybe the OP has just found an old book in the library, or a second-hand bookshop, or a skip, or something...

"or are you in school being taught by an instructor that is too lazy to update to current technology?"

If this is purely a (school) exercise in interfacing something to an 8051 (or derivative), then it's probably perfectly worthwhile for the purpose of the exercise.
In this case, the school would presumably provide the necessary materials (datasheets, etc) as handouts, in textbooks, or whatever.
This would seem like a perfectly valid exercise in reading a datasheet & implementing its requirements - just so long as the students understand that it is not an illustration of current practice!