Re: Daisychaining 5.25 " Drives

["Bill Garber" <willy46pa@comcast.net>]

"Michael J. Mahon" <mjmahon@aol.com> wrote in message
v_CdnRDToe4jUJjYnZ2dnUVZ_uudnZ2d@comcast.com">news:v_CdnRDToe4jUJjYnZ2dnUVZ_uudnZ2d@comcast.com...
: Don Bruder wrote:
: > In article <UIidnZ0empu7CpjYnZ2dnUVZ_q2dnZ2d@comcast.com>,
: >  "Bill Garber" <willy46pa@comcast.net> wrote:
: >
: >
: >>"Mark Percival" <mark@syndicomm.com> wrote in message
: >>1157993693.674164.148300@e3g2000cwe.googlegroups.com">news:1157993693.674164.148300@e3g2000cwe.googlegroups.com...
: >>:
: >>: Robert O Greenawalt wrote:
: >>: > Who knows the limit of daisychaining such drives with one controller
: >>card?
: >>:
: >>: Two drives per card.  I'm not sure which 3rd party controller card
Bill
: >>: is refering to.
: >>:
: >>: Mark
: >>:
: >>: http://www.syndicomm.com/~mark/DM8/
: >>
: >>
: >>The Rana drive controller was one that I know of,
: >>but, that may have required Rana drives as well,
: >>I am not sure exactly. I'd have to research that.
: >
: >
: > No research needed - Even with the Rana controller, a standard
: > Apple-issue drive can't "pass along" to anything beyond drive 2 due to
: > the wiring of the connectors/logic on the drive boards (not the
: > controller card, but the drive boards)
: >
: > The second connector on the second drive is effectively a "dead end",
: > because the drive-select signal to turn on the second drive is "faked
: > up" in logic by the board of the first drive prior to the signals being
: > passed to the second connnector. Thus the second drive in the chain
: > always sees either "nothing at all" or "They're talking to me". The
: > first drive sees "They're talking to me", and the "faking up" process
: > puts a "nothing at all" signal on the second connector. If the first
: > drive sees a "We're NOT talking to you" signal, it fakes up the "We're
: > talking to you" signal and puts it on the second connector, and the rest
: > of the signals get routed to the second connector for drive 2 to play
: > with.
:
: No "faking up" is required.  Both drive select signals are present at
: the 19-pin controller connector, and each daisy-chainable drive simply
: acts on the "drive 1 select" and passes the "drive 2 select" on to the
: "drive 1 select" output on its daisy-chain connector.
:
: The Apple III first used this approach.
:
: -michael


So, as I implied, it's like 2 controllers
on a single card?

Bill Garber
Owner - Garberstreet Enterprizez
Co-owner - GSE-Reactive.com
(610)935-7676 (610)329-8996