My 1st computer 1970s. RCA 1802 VIP. Enter programs in hex and store to a cassette. Hand wired a 2K static memory board. Built a ccd light pen and wrote a program to play tic-tac-toe by pointing to TV.
Next computer was S100 bus with 8inch floppy and CP/M OS. Wrote real business programs on this. Created a database for big truck camper top dealer to manage inventory. Turned a GMC truck dealers huge parts cross reference files into a easy database. Moved an insurance company from typing policies on type writer to computers.