Building the System/360 Mainframe Nearly Destroyed IBM

This whole thing is very cool and worth reading.

BUT. I worked at a place that used IBM 360s. We ran stuff for engineers, a lot of Fortran along with assembly code. We had so much stuff going on we could not code up and run things fast enough. The engineer/scientist got frustrated.

Then one day an engineer brought in an Apple II from home and ran the programs on that.

The earth shook. The very ground beneath us moved. Tectonic plates shifted. The world was never the same again! I think it was Visicalc.

Later there were other things. Soul Of A New Machine. The Mac.

I wonder how the compute power of a current high end smart phone compares with and IBM 360? I know the graphics chip is better.

If I had to compare computers based on one number it would be the amount of RAM. The 360 had a 24 bit address space which could fit 16MB of RAM although only the largest installations, like the one at NASA, were that big. iPhone 16s have 8GB of RAM so you're talking 512 times the memory capacity, never mind that my desktop PCs are all loaded with 4-8x times that of the phone and you can definitely get a big server with a few TB.

An IBM 360/20 on the small side, however, ranged from 4kB to 32kB which was similar to home computers circa 1980, before it is routine to have a complete 64kB address space.

Where the 360 crushed home computers was in mass storage, 9-track tapes could store 80MB contrasted to floppy disks that stored less than 200kB. Large storage compared to memory meant a lot of focus on external memory algorithms, also there was already a culture of data processing on punched cards that translated to the 360 (e.g. terminals have 80 columns because punched cards had 80 columns)