Re: 200 apple II clones confirmed

[pausch@saaf.se (Paul Schlyter)]

In article <1157520987.848500.61740@e3g2000cwe.googlegroups.com>,
mdj <mdj.mdj@gmail.com> wrote:

> Michael J. Mahon wrote:
>> a2aviator@gmail.com wrote:
>>> Heh, wow.
>>>
>>> 200 clones.
>>>
>>> Only second to the IBM PC. ColuMBIa.. a mirror image. Columbia Computer
>>> Company, that was their ad.
>>>
>>> Not an easy feat and probably no other computer comes even close. I'm
>>> not gonna count CP/M machines as these were no more than use all common
>>> platforms, no one was really out to clone anything. Much like x86
>>> Wintel has become today.
>>>
>>> CP/M. The Wintel of yesterday.
>>
>> No, Wintel machines truly are clones.  There are just lots of
>> functionally identical ways of building them.
>>
>> When everyone implements the bugs along with the features, then
>> you know they're cloning.
> 
> Well, the PC wasn't much more than Intels reference design after all.
> 
> The thing that made it a PC, IBMs firmware was never completely cloned
> as far as I know, as the original machines included BASICA in ROM.
> However you only really had to clone the Firmwares BIOS interface to
> allow MS-DOS to boot.
> 
> This is in contrast to the the Apple II where software is dependant on
> a *lot* more of the ROM than just the BIOS. If it were that easy,
> clones would have been a lot more popular. However to do it 'properly',
> you really had to license AppleSoft from Microsoft, which AFAIK only
> the Laser and Franklin clones did correctly.
> 
> Matt

One thing which made the Apple II firmware harder to clone than the
IBM PC firmware was (besides the dependency of a ROM based Basic in
the Apple II) that the entry points into the Apple II monitor was at
fixed addresses.  The entry points into the IBM PC's ROM BIOS was
through soft interrupts, which made it possible to move around the
actual code freely within the ROM BIOS address space - that was
impossible to do with the Apple II monitor ROM if you wanted old
programs to continue working with it.

Also, the Apple II Monitor ROM was only 2K, while the IBM PC ROM BIOS
was 8K.  True, the IBM PC ROM BIOS was more complex, but not that much
more complex.  SO the code hadn't to be as "tight" in the IBM PC ROM
BIOS as it had to be in the Apple II Monitor ROM.

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