Records have had "format wars" from the beginning. Early on it was cylinder vs. disc, then lateral vs. vertical grooves. By 1920, the 78 RPM disc had won, and except for a few scattered experiments, was the standard way for a consumer to hear recorded music for over 25 years. In 1948, Columbia Records introduced the LP, the 33 RPM long-playing record. Suddenly one side of a 10-inch record could play for 15 minutes instead of for three. A 12-inch LP could have 20 or more minutes per side instead of five.
RCA Victor retaliated with the seven-inch 45 RPM single and EP. The former was designed to replace the 78; the latter could hold around seven or eight minutes at most per side, although six minutes per side was more usual. Two formats competed for awhile, and the two companies wisely agreed to cross-license the two formats with each other and with other companies. The market soon sorted things out - consumers decided against the 10-inch LP and the seven-inch EP, preferring the 12-inch LP for albums and the seven-inch 45 for singles.
But for whatever reason, the betwixt-and-between 45 RPM EP remained popular in Europe into the 1970s. Here's an example, apparently recorded for that format. In the summer of 1960, New Orleans clarinetist Edmond Hall (that's the preferred spelling) toured Czechoslovakia and Hungary - then both behind the so-called "Iron Curtain." Backing was provided by the big band of Gustav Brom, a well-known Czech bandleader. Although the band was not the equal of its best American counterparts, it was pretty good, and Hall and the Czech musicians soon formed a mutual admiration society. After one Prague gig, the band was put up in a cheap hotel, while Hall was offered a suite in a hotel for VIP visitors. Hall turned down the offer, and stated that he would be staying with his colleagues.
I should say something about the great Edmond Hall. He was born 1901 in Reserve, Louisiana, 40 miles upriver from New Orleans. He moved to New Orleans when he was about 18, and after some musical success there, moved to New York. There, during the 1930s and 1940s, he established a reputation as a fiery, creative, and reliable clarinetist who was influenced as much by Benny Goodman as by the music of New Orleans. He had a stint in Louis Armstong's All Stars, and was perhaps the best clarinetist in the various incarnations of that band.
This cool four-song EP was issued on the Czech label Supraphon. Here's the opening track, a Hall original called "Swingin'" - or "Tančíme" in Czech.