On 4/9/24 23:51, Van Snyder via cctalk wrote: > I don't remember whether it was one of the docents at Haus zur > Geschichte der IBM Datenverarbeitung at Sindelfingen, or at the > Computer History Museum at Mountain View, who told me that IBM was > developing a machine to be designated 1480, as part of the 1401-1440- > 1460-1410 series, with newer technology, roughly contemporaneously with > the 360. When IBM decided to put all its eggs in the 360 basket, The > 1480 team somehow survived and produced either the 360/20 or 360/25. An > 8k machine would be a bit weird in this series, since 1410 was already > 100k. Does anybody know more details about this?
The model 20 could have between 4K-16KB memory initially; later it was expanded to a maximum of 32K. The model 30 was configured with a minimum of 8KB up to 64KB. I'm not sure if DOS/360 could run in 8KB; I don't know how common 8KB model 30s were, but I've never seen one. The big difference is that the model 20 is really a 16-bit machine, with 16-bit general registers and a very pruned-down instruction set with a considerable number of differences from the bigger systems. --Chuck
