When we’re introduced to the Stargate, it’s in the early-mid 90s, so them needing a big, bulky computer system would make sense, but as the show progresses, we see Tau’ri computer technology develop, either conventionally in the form of laptops like what the Atlantis team use, or computer crystals like what they fitted onto their starships.
Through it all, however, the SGC continues to use the same computer with comparatively dated hardware. Why keep it, instead of upgrading it to something more modern? Especially since one of the main issues that the SGC kept facing was that their dialling computer was not sophisticated enough to respond to some of the status codes put out by the stargate, causing all kinds of unpredictable behaviour.
When I was job hunting prior to graduating from college in 1990 with a computer science degree I interviewed with the Electric Boat division of General Dynamics. They build the US Navy’s submarines. I’ll never forget being told how their systems were programmed via punch cards. Those cards were then sent off to a company that converted them into a magnetic tape that was then installed on the subs. I was shocked that anybody used punch cards in the 90’s, especially our military…