Explaining the 24-bit Base Registers · [Herewith an appearance by a guest author, name of John Fowler; explanation in the coda at the end]. I attended the IBM 360 40yr Anniversary at the Computer History Museum in Mountainview, California. I'm on their mailing list and went there for the sole purpose of finding out: what the heck were they thinking with the use of 24 bit addressing in base registers that were 32 bits wide? ...