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From: kiki@uhunix1.uhcc.Hawaii.Edu (Jack W. Wine)
Newsgroups: comp.sys.atari.st.tech
Subject: Re: SCSI chip project
Message-ID: <12839@uhccux.uhcc.Hawaii.Edu>
Date: 3 May 91 23:37:11 GMT
References: <12824@uhccux.uhcc.Hawaii.Edu> <5578@wucc.waseda.ac.jp>
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In article <5578@wucc.waseda.ac.jp> ytsuji@wucc.waseda.ac.jp (Y.Tsuji) writes:
>I just cannot understand why we need to worry which chip to install on
>ATARI ST, Wd1772 or NCR???  Let ATARI manage to procure a floppy disk
>controller or SCSI controller. Do you think ATARI will listen to us?
>I am not so sure that USENET reflects the opinions of the vast majority of
>users (games or music people).

This project would be primarily for people who don't have the Mega STe/TT,
because Atari supposedly will provide some type of floppy upgrade kit for
the Mega STe and TT owners.  That leaves several million ST owners who pro-
bably want a HD or VHD drive, with the alternative of the Dreampark floppy
kit you cited in another post, or an embedded-SCSI floppy with a SCSI adaptor.

I can think of these advantages to my proposal:

1) Following ANSI specs will allow connection to peripherals 18 ft. (6 m) away.
2) Enhanced reliability because of ANSI conformance
3) Low chip count, compared to commercial SCSI adaptors.
4) Internal design
5) Cheap (~$10 for NCR 5380 and ~$20 for other parts)

Some disadvantages:

1) Like Dreampark kit, requires desoldering floppy chip
2) Requires wire wrap equipment (~$10)
3) Interfacing to TOS may be difficult.
4) Case must be modified to install a connector

The hardware part appears to be straightforward, but TOS will be a little
confused!  If anyone has any ideas about adapting it to TOS, please let me
know.

For most people, the ICD SCSI adaptor would be a good alternative, but for
people using their ST's with numerous peripherals which are constrained by
the electrical limitations of the DMA port, this project may be a practical
solution.  The combination of the ICD SCSI and the NCR chip SCSI would make
the ST a pretty formidable machine.
 
Jack