[comp.sys.amiga.hardware] Questions

frix@hexagon.se (Fredrik Rothamel) (09/03/90)

I have a couple of questions that I hope someone could find some answers
to, or at least pointers to info about.

1. Autoconfig (tm)
	How does it work ?

2. RAD:
	How does the Amiga know if and where a RAD: disk is present when
	it boots ?

3. SCSI
	What signals does a SCSI drive need/send.

-- 
Fredrik Rothamel
Internet:		frix@hexagon.se
UUCP:			sunic!kullmar!pkmab!hexagon!frix
Snail:			Syrenvaegen 9, S-702 20  OEREBRO, Sweden

lphillips@lpami.wimsey.bc.ca (Larry Phillips) (09/04/90)

Such short questions, but oh so large and complex answers....

In <678@hexagon.se>, frix@hexagon.se (Fredrik Rothamel) writes:
>I have a couple of questions that I hope someone could find some answers
>to, or at least pointers to info about.
>
>1. Autoconfig (tm)
>	How does it work ?

Briefly, a signal is sent out on the Zorro bus, which is intercepted by the
first autoconfig card in the chain, and at the same time, a READ is performed.
If the data from the READ makes sense, more stuff is read, and the program
querying the bus knows from the data, what kind of card it is, and what
resources it requires. The program then tells the card what address(es) it
occupies, and the card latches that information for any further communication.
At this point (give or take a few things), the card stops answering to the
autoconfig address and passes the config signal on to the next card in line.
This continues until there are no more cards to be config'ed.

For more detailed information, see the A500/A2000 Tech Ref Manual, and the
expansion.library autodocs.

>2. RAD:
>	How does the Amiga know if and where a RAD: disk is present when
>	it boots ?

A special structure is placed in memory. On bootup, this structure is located
and acted upon, and in the case or RAD:, will cause the OS to set up a RAD:
device again and protect the memory used from being stomped on.

For more information, see the autodocs and includes, especially the parts about
ROMTAGs.

>3. SCSI
>	What signals does a SCSI drive need/send.

8 bits for data, and a variety of control signals. The spec for SCSI is
relatively complex. Basically, the control signals determine the interpretation
of the contents of the data bus, which can be taken as selection, commands,
messages, status, or data.

For more information, see the SCSI specification, or data sheets for any of the
SCSI conttroller chips.

-larry

--
It is not possible to both understand and appreciate Intel CPUs.
    -D.Wolfskill
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|   //   Larry Phillips                                                 |
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red@ALESSIA.DEI.UNIPD.IT (Piergiorgio Sartor 274199) (03/19/91)

How can I expand an A2000B to ECS?
Does A3000 use 68030's MMU?
In A3000 the audio chip is the old one, why no DSP, like NeXT?
Please reply also via e-mail, I've troubles in reading NNTP now.
-- 
					red@alessia.dei.unipd.it

mwed381@nmt.edu (Mike Worley) (05/01/91)

     Just a couple of questions...


1) I'm looking for a hard drive controller/memory board for my A500
   I would prefer the memory to use sims. Anybody have any suggestions,
   comments, or willing to give me one for "free"?

2) Does anybody know the phone number for the Commodore Home offices in 
   the US? I'm a bit pissed off at them and need to find the source of my 
   problems and (various descriptions deleted). It might also give me peace
   of mind.

   Email or Post any comments...


			Thanks

			   Mike Worley

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What do you do with a drunken sailor...put him incharge of an exxon tanker.

Mike Worley					         mwed381@nmt.edu
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