Why are they referred to as "Sarisim" of Pharaoh?
Targum Onkelos and Targum Yonasan: They were important officials. Refer to 39:1:2:1 .
Ramban: Both the butler and the baker served the women as well, and kings would customarily castrate the men who worked in the women's quarters.
QUESTIONS ON RASHI
Rashi writes (to 40:1) that a fly was found in the wine, and a pebble in the bread. The latter is a worse sin! Why does it say that "Pharaoh was angry with Sar ha'Mashkim and Sar ha'Ofim" - which implies that he was more angry with the former?
Malbim: The Sarim served the wine and bread; they did not make it. It was greater negligence that the Sar ha'Mashkim did not notice the fly in the cup. How could the Sar ha'Ofim know that there was a pebble in the bread?! His only sin was appointing a baker who was not careful. 1
Ha'amek Davar: It repeats "v'Al" to teach that each sinned independently. (Perhaps Sar ha'Mashkim is mentioned first, for that episode occurred first!)
Malbim: It is indeed illogical that Pharaoh should kill the Sar ha'Ofim, and not the Sar ha'Mashkim. Therefore, it was clear that Yosef interpreted the dreams through Ru'ach ha'Kodesh.