On Thu, 2004-09-09 at 12:37 -0700, Karl Hegbloom wrote: > On Thu, 2004-09-09 at 00:33 -0500, Ron Johnson wrote: > > On Wed, 2004-09-08 at 20:48 -0700, Karl Hegbloom wrote: > > > On Wed, 2004-09-08 at 08:45 -0500, Ron Johnson wrote: > > > > Back when segments were 16 bits wide, yes it was a pain. I'm old > > > > enough to have done assembly programming on the 8088. (Now that I > > > > have the wisdom of time, I understand why Intel did what they did, > > > > even though the 68K was much cleaner.) > > > > > > ? Well, so why did they do it that way? > > > > They? Motorola or Intel? > > Well, both then. Why did each make the design choice they made wrt > segmentation vs a 'flat' address model? Segmentation allowed a smoother software upgrade for existing 8080 programs, whereas the 68000 is forward-thinking, a clean break with the 6809. From rom a business perspective, Intel's segmented method is better, but from a technical point, the 68K-way is better. For example, IBM was able to easily use existing 8 bit peripheral parts in the design of the PC, but Motorola had to design all new support parts for the 68K. IOW, low-cost and time-to-market was valuable, even then. -- ----------------------------------------------------------------- Ron Johnson, Jr. Jefferson, LA USA PGP Key ID 8834C06B SpaceShipOne powered flight: #1 : 17 December 2003 - 1497k/h, 20400m, 15 sec thrust burn #2 : 8 April 2004 - Mach 2, 31500m, 40 sec thrust burn #3 : 13 May 2004 - Mach 2.5, 63420m, 55 sec thrust burn #4 : 21 June 20004 - ~2400k/h, 100125m, 70 sec thrust burn
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