Re: Apple II ROMs?

[Ernest <leucoplast@seanet.NOSPAM.com>]

RedskullDC wrote:

> Hi Ernest,

Hello!

>> I have one late model clone board that only has the Monitor ROM on the
>> motherboard, and two additional ROMs on an expansion card. The card ROMs
>> are different sized -one 16k and one 32k. The card has room for two
>> additional ROMs but they were never added. However, the system Autostarts
>> from a disk drive, and it loads Applesoft on startup (with no disk in the
>> drive.) I don't understand how they were able to do so much with those
>> two ROMs?
 
> If you are electronically minded, check to see if the the motherboard's
> /INH signal is grounded by the insertion of the ROM card, effectively
> overlaying the motherboard ROM space.

I think that with a bit of training/experience, I would be very
electronically minded but as things are, I'm left out in the cold with this
stuff. I'm curious to the point, though, that I'm sometimes maddened by my
inability to get my mind around the inner workings of the old computers
that I've collected. I would compare it to trying to understand written
Chinese without any training. I look at all those chips on the motherboard
and wonder, "what does it all mean?"
 
> Is this a BASE64 by any chance?
> 
> The BASE64 (and a few other clones) had a function key, that in
> combinatuion with the other keys on the keyboard, produced all of the
> normal FP BASIC commands from the single key-press.

I do have a Base 64 but the computer that I was refering to is the OS-22. In
fact, now that I look at it again, I don't even see a Monitor ROM on the
motherboard. The only "ROMmy" looking ROM chip on the board is the
Character Generator. The ROM add-on Card has two chips -C-103 and a 2732. I
can't remember what the C-103 chip does. Is that the Apple Monitor? The
motherboard has both a Z80a and a um6502.

The Base 64 is a slick little clone. It has Basic, Tiny-Assembler, and a
menu-driven text editor called Mini-Writer -all in ROM. I haven't played
with this system much but I've been curious to play around with the F1/F2
keys. I really like the keyboards that have extra functions written on
them, like the Base 64's keyboard. 

> Neat way of expanding some of the monitor routines, or add the mini-assem
> to Autostart for example.

Is that what they did with the Base 64?

>> I have a Basis 108 that uses six 32k ROMs. Each ROM is somehow divided
> into
>> two halves. By using a switch before startup, the system can be set to
>> use either Basis Basic or Applesoft. In otherwords, each of the six ROMs
>> contains code for both versions of Basic. Could the six Basis Basic ROMs
> be
>> compressed into three 32k ROMs instead of six 16k ROMs? Or does the
>> computer look for different parts of the software at different address
>> locations?
> 
> Previous case is true with the Basis.

I just re-read what I wrote above, and I didn't explain what I meant very
well, when I used the term "address." What I meant was does the Apple II
(or II clone) look for certain information on a ROM that is located in a
particular ROM socket, or does it look for things in a different way that
has nothing to do with the particular ROM (EO for example) or physical ROM
socket? Is it all, more or less random, in terms of ROM label or location?

Could you reverse ROM F0 with EO on the motherboard?