john.lohmeyer at symbios.com
Fri Apr 3 10:44:29 PST 1998
* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* John Lohmeyer <john.lohmeyer at symbios.com>
All of the T10 Committee draft standards can be found on the T10 Web site at:
I recommend that you also visit the SCSI Trade Association's web site at:
SCSI keeps evolving, particularly at the hardware level. The hardware
Name date ANSI designation Comments
------- ---------- -----------------
SASI circa 1981 (now obsolete) Asynchronous data transfers only ~ 1.5
SCSI 1986 (now obsolete) Up to 5 MByte/sec
SCSI-2 1994 X3.131:1994 Up to 10 MByte/sec on using
SPI 1995 X3.253:1995 Up to 10 MByte/sec plus wide SCSI
Fast-20 1996 X3.277:1996 Up to 20 MByte/sec (a.k.a., Ultra SCSI)
SPI-2 current draft standard Up to 40 MByte/sec (a.k.a., Ultra2 SCSI)
SPI-3 newly-approved project Up to 80 MByte/sec (probably will be
The above table grossly over simplies a number of things.
SPI-2 introduces an new driver/receiver type called Low Voltage
Differential (LVD). It enables the higher data rates. Many new products
support both LVD and the older single-ended drivers/receivers. These
products are called multi-mode or universal.
SPI-3 is the gleam in the standards committee's eye. We do not yet have a
first draft of SPI-3.
i hope this helps!
John Lohmeyer, Chair T10 Technical Committee
At 4/2/98 09:10 AM, you wrote:
>* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
>* Andreas Koch <koch at aimnet.com>
>Please pardon my total ignorance, but would anybody be so kind to take a
>moment and explain to me briefly what the differences are between Ultra-2
>SCSI and SCSI-2/3 and where I could find the standard spec. (I could only
>find SCSI-2 related documents on ansi.org).
>koch at aimnet.com
John Lohmeyer Email: john.lohmeyer at symbios.com
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