Which system introduced earlier than 1981 has an internal hard disk of 11 megabytes and less than 21 s-100 slots?
CREATE TABLE table_name_47 (system VARCHAR, internal_hard_disk VARCHAR, s_100_slots VARCHAR, year_introduced VARCHAR)
SELECT system FROM table_name_47 WHERE s_100_slots < 21 AND year_introduced < 1981 AND internal_hard_disk = "11 megabytes"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_name_47 (system VARCHAR, internal_hard_disk VARCHAR, s_100_slots VARCHAR, year_introduced VARCHAR) Question: Which system introduced earlier than 1981 has an internal hard disk of 11 megabytes and less than 21 s-100 slots? [/INST] SELECT system FROM table_name_47 WHERE s_100_slots < 21 AND year_introduced < 1981 AND internal_hard_disk = "11 megabytes" </s>