A Piper on the Hob is a house cricket. During the colder nights the presence of a cricket was said to be a sign of good luck. Confusingly, there is another musically unrelated Irish jig of the same name (see the last link below).
This tune was first published in George Petrie's 1850's collection under the title Tear the Callies. It was popularized around 1975 under the Kesh title by the Bothy Band. Kesh is a village in County Fermanagh, Ireland, near Lough Earne.
The melody was first printed by George Petrie in the mid-19th century under the title The Bucks of Ahasnagh. It may be a variant of the 17th century lowland Scots tune named Rock and a Wee Pickle Tow, which was a women's spinning song.