The CD was planned to be the successor of the gramophone record for playing music, rather than primarily as a data storage medium. From its origins as a musical format, CDs have grown to encompass other applications. In 1983, following the CD's introduction, Immink and Braat presented the first experiments with erasable compact discs during the 73rd AES Convention. In June 1985, the computer-readable CD-ROM (read-only memory) and, in 1990, CD-Recordable were introduced, also developed by both Sony and Philips. Recordable CDs were a new alternative to tape for recording music and copying music albums without defects introduced in compression used in other digital recording methods. Other newer video formats such as DVD and Blu-ray use the same physical geometry as CD, and most DVD and Blu-ray players are backward compatible with audio CD.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What was the CDs predecessor?
Ah, so.. gramophone record

In the 14th century, much of the Greek peninsula was lost by the Byzantine Empire at first to the Serbs and then to the Ottomans. By the beginning of the 15th century, the Ottoman advance meant that Byzantine territory in Greece was limited mainly to its then-largest city, Thessaloniki, and the Peloponnese (Despotate of the Morea). After the fall of Constantinople to the Ottomans in 1453, the Morea was the last remnant of the Byzantine Empire to hold out against the Ottomans. However, this, too, fell to the Ottomans in 1460, completing the Ottoman conquest of mainland Greece. With the Turkish conquest, many Byzantine Greek scholars, who up until then were largely responsible for preserving Classical Greek knowledge, fled to the West, taking with them a large body of literature and thereby significantly contributing to the Renaissance.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): At the start of 15th century, the biggest Byzantine city was what?
Ah, so.. Thessaloniki

During 1889, Thomas Edison had business interests in many electricity-related companies: Edison Lamp Company, a lamp manufacturer in East Newark, New Jersey; Edison Machine Works, a manufacturer of dynamos and large electric motors in Schenectady, New York; Bergmann & Company, a manufacturer of electric lighting fixtures, sockets, and other electric lighting devices; and Edison Electric Light Company, the patent-holding company and the financial arm backed by J.P. Morgan and the Vanderbilt family for Edison's lighting experiments. In 1889, Drexel, Morgan & Co., a company founded by J.P. Morgan and Anthony J. Drexel, financed Edison's research and helped merge those companies under one corporation to form Edison General Electric Company which was incorporated in New York on April 24, 1889. The new company also acquired Sprague Electric Railway & Motor Company in the same year.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): In what year did Drexel, Morgan & Co. begin to finance Edison's research and form Edison General Electric Company?
Ah, so..
1889