The Irish system is actually Single Transferable Vote for all National (Parliament and Senate, no less than every 5 years), Local and European elections (both every 5 years), meaning you number the candidates in order of preference from 1, 2, 3... and so on until however many you wish to vote for, with a number of candidates elected in each voting constituency (that number depending on the size of the electorate in that constituency.
For Presidential Elections (every 7 years), Single Transferable Vote - Instant Run-off is used (number candidates in order of preference, but only one candidate will be elected), and Referenda are simple yes/no questions.
Counts can take quite a while as the candidates with the lowest votes per count are eliminated and their votes distributed to their second preferences. Here's an from my constituency in the 2011 National elections which demonstrates how it works, and the tally lasted about 14 hours.
http://www.rte.ie/news/election2011/results/dublin-north-central.html
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The Irish system is actually Single Transferable Vote for all National (Parliament and Senate, no less than every 5 years), Local and European elections (both every 5 years), meaning you number the candidates in order of preference from 1, 2, 3... and so on until however many you wish to vote for, with a number of candidates elected in each voting constituency (that number depending on the size of the electorate in that constituency.
For Presidential Elections (every 7 years), Single Transferable Vote - Instant Run-off is used (number candidates in order of preference, but only one candidate will be elected), and Referenda are simple yes/no questions.
Counts can take quite a while as the candidates with the lowest votes per count are eliminated and their votes distributed to their second preferences. Here's an from my constituency in the 2011 National elections which demonstrates how it works, and the tally lasted about 14 hours. http://www.rte.ie/news/election2011/results/dublin-north-central.html