[sci.electronics] SASI

alz@tc.fluke.COM (Al Weiss) (10/11/88)

In article <298@entec.Wichita.NCR.COM> jlohmeye@entec.UUCP (John Lohmeyer) writes:
>You are very close to right, but it actually is "Small Computer System
>Interface" -- System is not plural. My credentials, BTW, are that I was the
>technical editor of the ANSI SCSI standard (There are three SCSI standards:
>ANSI X3.131-1986, Standard ECMA-111, and ISO IS 9316.) 

Thank you John for mentioning all three standards.  But as long as we are on
it would you or someone else fill in one more blank; What is SASI (Shugart
Associates System Interface) and how does it fit into the history of the three
standards mentioned above?

Thanks,
Al

henry@utzoo.uucp (Henry Spencer) (10/12/88)

In article <5493@fluke.COM> alz@tc.fluke.COM (Al Weiss) writes:
>>... (There are three SCSI standards:
>>ANSI X3.131-1986, Standard ECMA-111, and ISO IS 9316.) 
>
>... What is SASI (Shugart
>Associates System Interface) and how does it fit into the history of the three
>standards mentioned above?

It's the somewhat-simpler-somewhat-more-vaguely-specified ancestor of
all of them.
-- 
The meek can have the Earth;    |    Henry Spencer at U of Toronto Zoology
the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu

jlohmeye@entec.Wichita.NCR.COM (John Lohmeyer) (10/12/88)

In article <5493@fluke.COM> alz@tc.fluke.COM (Al Weiss) writes:
>
>But as long as we are on
>it would you or someone else fill in one more blank; What is SASI (Shugart
>Associates System Interface) and how does it fit into the history of the three
>standards mentioned above?
>
>Thanks,
>Al
Well, since you asked, I'll give you the short history... :^)

SASI was the original document from which ANSI, ECMA, and ISO SCSI were 
developed. SASI came from Shugart Associates around 1980. They farmed out
controller development for SASI to a couple companies (most notably DTC) and
made an effort to promote it as an industry standard.  I got involved with 
SASI and Shugart Associates in 1981. We (NCR) and Shugart decided to team up
and propose it as the basis for an ANSI standard. After some politics, it
got started in X3T9.2 (a standards committee that I now chair) in April 1982.
A year later, Shugart and NCR got a SCSI project started in ECMA (European
Computer Manufacturers Association).

In November 1985, We (the U.S.A.) proposed SCSI as an international standard
to the ISO (International Standards Organization) standards committee TC97/SC13.
This standard was based on the draft ANSI SCSI standard with a few changes
from the ECMA standard. (We "backed" these changes into the ANSI standard to
keep them the same.) So, all of these standards come from SASI originally.
But SASI was about 22 pages long at that time. And only 2 of these pages
described the Disk command set (SASI had no other command sets). The formal
SCSI standards are about 10 times larger (and SCSI-2 is now up to 555 pages).
As you can see, SCSI really was mostly defined by committee -- perhaps, it
deserves its "skuzzy" pronunciation :^).

I hope you aren't sorry you asked.

John Lohmeyer      j.lohmeyer@Wichita.NCR.COM