link to some intresting history on recordings.
The 78 came first, then the 33 1/3 which held multiply songs. The 45 was put out to hold 1 or 2 songs.
From the link,
"Recording technology really took off after world war two, but one of the biggest developments wasn't a product of the military. It happened because of the music played at a dinner party in the fall of 1945. And believe me, this little party changed everything.
In the autumn of 1945, Mack and Helen Morgan of Westport, Connecticut, held a dinner party and as all good hosts do, they provided some background music on their phonograph. It was mostly classical music; Beethoven, Bach and especially Brahms. One of the guests at the party was Dr. Peter Goldmark, who happened to be a big fan of Brahms, and he was mad...
See, in 1945, the only thing you could play on a phonograph was a 78-rpm disc. 78s were made mostly of a brittle material called "shellac." They were noisy, scratchy and-worst of all-limited to storing a maximum of four minutes of music per side. So if you wanted to play, say, Brahms' "Piano Concerto No. 1 in D Minor, opus 15," you had to get up every four minutes and either flip the record over or change it. To get through the whole thing might take ten, twelve or more discs.
This, thought Dr. Goldmark, was not how Brahms intended his music to be heard, so he vowed to do something about it. And he could because Dr. Goldmark was not a medical doctor, he was an engineer...
First, he did a little research: He discovered that 90 per cent of all his favourite classic works were less than 45 minutes. He then started work on a system that would allow up to twenty-five minutes of uninterrupted listening. Dr. Goldmark hooked up with CBS records and in 1948, on a summer day at the Waldor-Astoria hotel in New York, his new invention was unveiled.
It was a twelve-inch piece of vinyl that played not at 78 rpm but 33 and a third. It was called "the long-playing record" or "LP." Why 12 inches? No reason; it seemed to be a nice size and would fit on the turntables of the time. And why 33 and a third? There's no magic reason. In 1931, RCA briefly dabbled in a disc like this for use in movie theatres. It ran about twenty minutes a side, which was about the same length as a standard movie reel. It just seemed like a good place to start.
The long-playing record changed everything, obviously. We came to call it an album. And you know why? Think back to that dinner party in 1945; all those separate 78 records had to be stored somewhere. They were kept in paper sleeves that were bound together in a collection-a book-that you could keep on a shelf. Instead of a photo album, you had a record album. And even after all those songs could be put onto just one record, we kept the name: "album." So today, if you buy any vinyl album, you should think back to that dinner party in 1945.
The company that introduced the LP record in 1948 was CBS; their rival was RCA. When the LP was ready, CBS chairman William Paley offered to share the technology with RCA. But the chief executive at RCA-a guy named David Sarnoff-would have none of it. The great sound of the LP embarrassed him, so he ordered his engineers to come up with something better.
Sarnoff didn't believe in putting songs together on one piece of vinyl. He liked individual songs on each side, just like the old 78. That's why (in early 1949), RCA released their answer to the LP. Code name: "Madame X." The seven-inch single that played at 45 rpm. And instead of a nice small hole in the centre, it had this giant thing...
Ever wonder about that? Why do 45s have such a big hole? Because RCA also made turntables. They wanted to control the future development of turntables and, in the process, eradicate the LP. With a large hole, you couldn't play a 45 on the same turntable as a 33 and a third LP. If you chose the seven-inch, you had to buy an RCA turntable.
Of course, this strategy didn't work. The industry adopted both the LP and the seven-inch, especially after rock'n'roll came along in the 50s and the concept of the "single" was born. And ever since 1949, we've become accustomed to turntables with two speeds: 33 and a third and 45. And now you know why: a battle of egos between David Sarnoff of RCA and William Paley of CBS."
