This message is from the T13 list server.
Most things in SCSI are optional. That's why they got into the standard
("please vote for it - afterall, you don't have to implement it if its
optional") but it does make a mess out of planning for what is "really"
supported.
That's why I always advise host guys to cut the fancy s**t and just stick to
the basics (INQUIRY, READ, WRITE). Trying to use everything in the standard
is like writing a memo using every font on the PC - very artistic, but
hardly very usable.
Jim
-----Original Message-----
From: Pat LaVarre [mailto:[EMAIL PROTECTED]]
Sent: Thursday, March 21, 2002 1:09 PM
To: [EMAIL PROTECTED]
Subject: Re: [t13] X-to-ATA bridges and R/W LONG
This message is from the T13 list server.
>>> Hale Landis 03/21/02 11:27AM >>>
> Can anyone answer...
> Do USB-to-ATA bridges support R/W LONG?
> Do 1394-to-ATA bridges support R/W LONG?
I'm not sure I understand the question ... I think I remember in Scsi r/w
long is a standard device design OPTION, not a standard device feature. So
by
people can only answer device by device whether they chose to implement the
option or not?
Any fully transparent Usb-to-Atapi bridge, or a fully transparent Ata over
whatever bridge, supports r/w long together with everything else possible,
by
the definition of "fully transparent".
I did see that the last two Usb-to-Ata and 1394-to-Ata devices that I
touched
in detail personally (Summer, 2001) translated optional Scsi ops x3E/3F
Write/Read Long to Ata ops x23/33 Read/Write Long after getting Ata op
xEF:44
SetFeatures VendorUniqueLongBlockLength to pass and fetching xEC Identify
data
to discover the VendorUniqueLongBlockLength.
I didn't appreciate that people found the T13 specs vague here, I'll have to
go dig in now.
> Do 1394-to-ATA bridges support R/W LONG? I have never seen one.
Did you mean you have never seen a 1394 to Ata bridge or did you mean to say
you know of bridges that do not pass thru Read/Write Long?
> Does "serial ATA" support the ATA R/W LONG command protocol?
I'm even more stunningly ignorant of Ata than I am of serial Ata ... so I'm
sure I don't really know what this query means.
Serial Ata is a bridge design, yes? Knowing just that much, given a block
size K, if serial Ata can't copy N * 2 bytes just because N * 2 != K, then
(a)
serial Ata can't talk Atapi and (b) serial Ata ain't a transparent bridge
design.
x4402 Pat LaVarre [EMAIL PROTECTED]
http://members.aol.com/plscsi/
