2020-08-30 04:27:44 UTC
Someone said a Model 20 could be 32K another said 16K.
I checked Wikipedia, they say 32K.
I accessed Functional Characteristics using the Wikipedia link.
That gets the -01 version of the manual.
On page 1, it lists the storage sizes:
Main Storage consists of 4,096; 8,192; 12,288; and
16,384 positions of magnetic core storage.
I'm guessing the 32K is accurate and was implemented in later models.
(See how confrontation is uncalled for.)
As to whether disk was common, I'm going to take a wild guess and
say that disk was initially uncommon but later might have been more
common. The system I worked on was card only.
Disk would make more sense on the 32K model since the owner could afford
to be using the OS with 32K.
It's interesting that the 2311 disk which was also sold for other S/360
models has fixed sector sizes on the Model 20.
I always thought the variable block sizes on S/360 was a mistake.
It put too much complexity into user space. A pity IBM didn't sectorize
all of it's disk on all of it's models from the beginning.
Oh boy, I expressed another opinion, now someone is going to call me an
idiot. Oh well.