Rashi: It is called also Yatzi'a [Radak ? and Tzela]. It is a cell. There were three to the right of the gate and three to the left. They are next to the eastern wall of Ezras Nashim, on the outside, towards Har ha'Bayis. I derive this from "va'Yvi'eni El he'Chatzer ha'Chitzonah" (17) ? before this was outside; he had not yet entered inside.

Radak: They were inside the wall, in five places, one further inside than the other from the wall of Har ha'Bayis until the Mizbe'ach ? (a) Har ha'Bayis, (b) inside Har ha'Bayis ? the Cheil, (c) Ezras Nashim, (d) Ezras Yisrael, (e) Ezras ha'Kohanim.

Malbim: It is an expression of Asa (coming), for one who comes to the gate stands there before he enters. There were three on each side and they opened to the gate. On the inside was the Ulam, which was a Beis ha'Sha'ar that pertains also to the gate.

Rashi: The interior of each was a square; the side was six Amos.

Rashi citing Targum Yonasan: The wall between them; it was five Amos thick. Also in Midos (4:7) it says so (about Bayis Sheni).

Rashi: Inside the gate was an Ulam connected to the gate, like it explains. It jutted out 10 Amos into Ezras Nashim. At the end were doors and Mezuzos.

Radak: The verse discussed the outer Saf. Now it explains that there was also an inner Saf, by Ulam ha'Sha'ar. Also it was six Amos wide. The same applies to the second Saf (i.e. in the north, if here discusses the one in the south), even though it was not mentioned.

Malbim: The Ulam wall was to the side of the gate, and on one side it was next to the wall of the Chatzer. On the second side inside, it had a Saf. It is the Saf of the Ulam. It is called Saf ha'Sha'ar, for also the Ulam pertained to the gate.

Rashi, Targum Yonasan: On the inner side. Malbim ? this is because on the outside, it was by the wall and did not have a Saf.

Vilna Gaon: It is the side drawn to the Bayis, i.e. inside the Chatzer, from north to south.

Rashi: Its width covered the thickness of the walls of the Ulam, one on the right and one on the left.