1950 to 1959: Starting the Ascent of Digital Computers and Software - The Technical and Social History of Software Engineering - page 96

By the end of the decade, transistors and integrated circuits were well on their
way to universal adoption. Magnetic cores were used for internal memory. Mag-
netic tape and magnetic disks were used for external memory.
The combination of transistors, integrated circuits, and random-access data
storage were all on the critical path leading to the huge expansions of computers
and software in future decades. Seldom in history have so many important inven-
tions come to fruition in such a short time span.
Summary
At the start of the 1950s, computers were built by hand, and they each used thou-
sands of vacuum tubes. These custom-built early computers were used primar-
ily for military and mathematical calculations. By the end of the decade, com-
puters had become commercial products for both the military and businesses, and
they were manufactured using transistors and integrated circuits. Programming
these commercial computers was made easier by the early high-level languages
of COBOL, FORTRAN, and LISP. The occupation of computer programmer was
starting an ascending trajectory that would soon make it one of the fastest-growing
jobs in history.