My first programming job, also.
One Christmas in the late 70s I had three 5120s set up in my living room. I was programming a complete accounts receivable system with reporting and data entry (I was an accounting major, long before small colleges had CS degrees). When all three were running I could turn the heat off, and still have to open a window in the middle of winter. I paid off my college loans with those computers.
One thing not mentioned in any of the discussions was how impossibly slow the systems were. I ran the sieve program from Byte magazine a few years later and the results came out in last place.
I coded in BASIC and the IBM BASIC had a wonderful ISAM built right into the language that made it very easy to handle indexed files. If you have ISAM, you don't need a database.
I took my last 5120 to the the salvage yard 30 years ago. I still have some 8 inch floppies with the code for my very first programs. Unfortunately, I have no way to read them.