1890 -- the first year he is in a San Francisco city directory - Documents place his arrival in 1883.
residence address - 23 6th St
business name - G. Georgapoulo & Co

1891
business: 23 6th St.
restuarant

1892
business name: Alexander J. Kosta & John A. Stepston
restuarant
business: 23 6th St.

1893
(There are two businesses listed)
business name: Alexander J. Kosta & John A. Stepston
restuarant
business: 23 6th St.
----
business name: Alexander J. Kosta & Andrew Zamale
restuarant
business: 131 6th St.

1894
business name: Shepston & Kosta
residence: 539 Minna

1895 - (the first year the Baltimore Oyster House is in the directory)
business name: Baltimore Oyster House
business: 21 6th Street
residence: 947 Howard

1896, 1897, 1898
business name: Baltimore Oyster House
business: 21 6th Street
residence: 1022 Mission

1899
business name: Baltimore Oyster House
business: 21 6th Street
residence: 19 1/2 6th Street

1900, 1901, 1902, 1903, 1904 - a residence address is not listed
business name: Baltimore Oyster House
business: 21 6th Street

1905
business name: Baltimore Oyster House
business: 21 6th Street
residence: 570 7th Street

1907
business name: Kosta & Greevas
residence: 570 7th Street

1908-1909
business name: Kosta & Paras
residence: 570 7th Street

1909-1910, 1911
restaurant: 352 O'Farrell
residence: 570 7th Street

1911-1912, 1912, 1912-1913, 1914, 1914-1915
occupation: cook
residence: 570 7th Street
(Katherine) - his wife's name is noted in parens

1915-1916
residence: 570 7th Street
the word "lab" is noted
(Katherine) - his wife's name is noted in parens

1918
occupation: mgr. Varellas
residence: 570 7th Street

1919, 1920, 1921, 1922
occupation: cook
residence: 570 7th Street
(Katherine) - his wife's name is noted in parens

1923
residence: 570 7th Street
occupation: cook

1924
residence: 570 7th Street
His daughter Kalliopi is listed