On Tue, 17 Apr 2018, allison via cctalk wrote:
Looked at 8086 and decided it was a 8080 with a bag on the side.
It was and still is irrational.
In the days of assembly language and hand edited machine code,
An 8080 with a bag on the side made it extremely quick and easy to port
legacy (8080) code.
An 80286 can run almost all 8086 code without further modifications.
Each generation of the intel processors was easy to adopt with legacy
code. LATER, the code can be rewritten to take advantage of new
"features".
The alternative, to start from scratch and design it correctly, means that
instead of porting legacy code, everything needs to be written from
scratch. For example, in the 68000, you have a processor that is NOT
hampered by being a 6800/6809 with a bag on the side. And it took a while
before commercial applications were ready. Consider spreadsheets on the
Mac. Good ones became available, but it took a while.
OTOH, Micropro had 8080 originated Wordstar running on the 5150 in weeks.
It took them longer to edit the manuals than to port the code.
Likewise Supercalc, etc.
There are trade-offs between redesign with integrated features to do it
right, VS add-on kludge bags to have maximum compatability.
These days, with most stuff written in compiled high-level languages, it
becomes "merely" developing the new compiler.
'course the result of compiled high-level language is not comparable to
assembly/machine coding. It requires "Moore's Law" to compensate for the
slower final result.
--
Grumpy Ol' Fred [email protected]
