Design flaw in the SCSI spec?

Eric Smith spacewar at
Wed Jan 8 17:59:26 CST 2020

On Wed, Jan 8, 2020 at 4:44 PM jim stephens via cctalk <
cctalk at> wrote:

> The electronics of the SCSI interface were designed initially by the
> precursor to Adaptec.  At the time that the SCSI committee was formed,
> there was work by a number of companies.  Among them were HP, and the like.

There was no one common electronic design for SCSI. The electronic designs
were unique to many companies. The earliest implementations were
board-level interfaces consisting mostly of TTL. Early single-chip
implementations included those from NCR and Adaptec, though many others
came later.

While there were many companies involved in the standardization of SCSI,
the original SCSI 1 specification, ANSI X3.131-1986, was a relatively minor
elaboration on SASI, which had been developed exclusively by Shugart
Associates, hence the name SASI being an acronym of Shugart Associates
System Interface. Shugart Associates was an early maker of 8 inch floppy
drives and invented the 5 1/4 inch floppy.

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