Viruses reproduce inside host cells, producing thousands of identical copies. Over 5,000 virus species have been discovered. Viruses consist of genes, protein coat, and sometimes fat envelope. Spread through vectors in plants and infected bodily fluids in animals. Immune system usually eliminates viral infections, vaccines prevent some
ENIAC was completed in 1945 as first programmable electronic general-purpose digital computer. Designed by John Mauchly and J. Presper Eckert for US Army's Ballistic Research Laboratory. Cost $487,000, equivalent to $6.9M in 2023. Used 18,000 vacuum tubes and 70,000 resistors by end of operation
First word processor patented by Henry Mill in 1714. Christopher Latham Sholes created first recognizable typewriter in late 19th century. Mechanical systems could only change letter positions and fill spaces
Transistors replaced vacuum tubes in computing by 1960. IBM and seven major vendors dominated the market. Second generation computers used discrete transistors with various architectures. Magnetic core memory was dominant until semiconductor memory emerged
Computer hardware includes physical components like CPU, RAM, motherboard, and storage. Hardware differs from software in being rigid and easy to change. Computer systems combine hardware and software for usable operation
Computers were first used for calculations by ancient people with abacus. Antikythera mechanism was earliest known mechanical analog computer. Charles Babbage invented first programmable computer in 1822. ENIAC was first electronic programmable computer built in US in 1945