In Masechet Yoma 37b (see also 78b), Tosfot says:
והרב פור''ת פירש כפר''י
And the Rav Porat explains as Rabbenu Yitschak.
Is there someone who knows who is this rav.
(I have some assumptions that the name "Porat" has something to do with the name Yosef.)
R. Porat (or: don Bendit, הר"י פורת) was named Yosef b. Moshe [of Troyes]. "Porat" or "Bechor Shor" were recognized sobriquets for those named Yosef (taken from Birchot Yaakov, Gen. 49:22 & Birchot Moshe, Deut. 33:13). Contrary to Zacuto et al., Solomon Schechter (here) dismisses the notion that Porat was a son of Rashbam and only considers being a grandson a possibility. E.E. Urbach (Ba'alei Tosafos, Jer. 1968, pg. 99). rejects both views as being without basis and maintains Porat was not a son nor a grandson.
Incidentally, Urbach demonstrates (ibid. pg. 478) that the Tosafos on Yoma were edited by R. Meir of Rothenburg and actually cites the above Tosafos as an example proving his position. See also Urbach (loc. cit.) for a description of Porat's literary production.
According to Wikipedia this is R. Yosef ben Moshe of Troyes, a student of Rashbam.
Kore HaDorot (3:1) writes that some claim he was a son of Rashbam.
Hida also states that he was Rashbam's son (Shem HaGedolim: פ).
