🚀 go-pugleaf

In <33ED35AA.3707@ais.net>, NSalanb@ais.net writes:

]The other one, which is most commonly meant when talking about
]16/32 bit systems, such as "OS/2 is a 32 bit OS," refers to the
]segment/offset vs. flat memory model.  16 bit means segment/offset
]and 32 bit means flat memory.

]One should be careful to define which one is being discussed.

Even this isn't correct. The I386 and successors implement 32-bit offsets:
    forget off-hand the number of "address" bits in the selector 
    registers, but I think, again without checking as the point's not 
    particularly imprtant here, that the i386 can address 48 Gb of 
    physical memory (but it may well be 48 GFb virtual memory and a lesser
    amount of physical).

OS/2 has implemented a flat memory model but the processors do not require 
    it.

Many people confuse the bus width with the natural word size. On the i386 
    and successors, 68000 family, IBMm S/360 (except for the small models)
    and successors the natural word size is 32 bits. Other word sizes used
    in various computers have been 
    
4  (i4004) 
8  (i8008, 8080, z80) 
16 (8086, PDP-11 & lots of other minis)
24 CDC low 3000 series
32 lots - see above but add Z8000
36 Univac
48 CDC high 3000 series, early cybers (I think)
60 More CDC cybers (again, I think)
64 DEC Alpha and other RISC machines

I think the latest cybers went to 120 but I'm even less certain here.

For most of these I've no idea of the bus width other than that it varies 
    among models. It's entirely irrelevant to programmers.


Cheers
John Summerfield
Perth, Western Australia
OS2 support, IBM ftp search, LAN configuration info
   @ http://www.iinet.net.au/~summer/