Re: IIc + SmartPort behavior

[Michael J. Mahon <mjmahon@aol.com>]

Steven Hirsch <snhirsch@gmail.com> wrote:
> On 11/07/2011 12:07 PM, Peltier Cedric wrote:
>> Le 07/11/2011 13:54, Steven Hirsch a écrit :
>>> On 11/06/2011 11:36 PM, Michael J. Mahon wrote:
>>>> Steven Hirsch<snhirsch@gmail.com> wrote:
>>> 
>>>>> At this point, the primary issue with IIc+ is that it won't boot the
>>>>> spvhd. Both the IIgs and IIc+ try to access the spvhd a bit before its
>>>>> firmware comes ready, so you generally need an immediate Oa-Ctrl-Reset
>>>>> after powerup. Then, you can do PR#5 and boot from the internal 3.5
>>>>> diskette. When P8 comes up, as many as three virtual disks will be
>>>>> recognized (assuming you aren't using an ancient ProDOS 8).
>>>>> 
>>>>> I don't consider this any sort of show-stopper and I'm sure Cedric will
>>>>> sort out the firmware.
>>>>> 
>>>>> Steve
>>>> 
>>>> I'm a bit surprised that it doesn't keep mapping logical devices until it
>>>> runs out of mappable slots.
>>> 
>>> Apple's specs claim support for a total of (4) devices on the Smart bus.
>>> That limit appears to be real.
>>> 
>> 
>> Initialy the SPVHD was limited to 4 virtuals drives, but I pushed this limit
>> up to 10 virtuals drives after a discussion with Geoff Weiss. Prodos 8 2.0.3
>> seem to be able to map more than 4 devices using all available slots.
>> Nevertheless, some 8 bits applications don't handle nicely so much devices.
>> The devices limitation should be correlated with electrical limitation at the
>> time, and I suppose the maximum number of devices that Prodos 8 can handle
>> evolved to follow hardware evolutions.
> 
> The IIc+ Specifications on Apple web site (archives) state:
> 
> ".. allows a daisy-chain connection of up to three additional drives
> (Apple 3.5, Unidisk 3.5 or Apple 5.25)"
> 
> I'm guessing the firmware simply never polls for anything more than (3) attached disks.
> 
> Steve

But it's not firmware, it's the ProDOS Smartport driver, and its
capabilities increased with time. 

-michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon