9 Jul
2018
9 Jul
'18
10:58 a.m.
Someone working on simulating the scsi DIO board in MAME asked me about the scsi loopback
test plug. Anyone ever seen one? Is it just wires or are there active parts doing the
loopback?
9 Jul
9 Jul
11:27 a.m.
On 07/09/2018 11:58 AM, Al Kossow via cctalk wrote:
Someone working on simulating the scsi DIO board in
MAME asked me about
the scsi loopback test plug. Anyone ever seen one? Is it just wires or
are there active parts doing the loopback?
I've never heard of loopback related to SCSI. I have seen many external
terminators that someone may miss-identify as a loopback because it
seems quite similar to a loopback for serial / parallel.
Is this by chance what they are talking about?
--
Grant. . . .
unix || die
11:33 a.m.
No, it is specifically mentioned in the HP test tools manual 09800-90001 page II-82.
On 7/9/18 11:27 AM, Grant Taylor via cctalk wrote:
I've never heard of loopback related to SCSI.? I
have seen many external terminators that someone may miss-identify as a
loopback because it seems quite similar to a loopback for serial / parallel.
Is this by chance what they are talking about?
2:24 p.m.
Yea, it would have to be more than just a terminator as it would have to reflect back
some
of the control signals to the ?ack? equivalents otherwise the controller would just see a
bus
with no devices on it. Presumably, the controller also has a ?loopback? mode so that all
the
signals (including data) could be read/written and therefor checked.
TTFN - Guy
On Jul 9, 2018, at 2:05 PM, Grant Taylor via cctalk
<cctalk at classiccmp.org> wrote:
On 07/09/2018 12:33 PM, Al Kossow via cctalk wrote:
No, it is specifically mentioned in the HP test
tools manual 09800-90001 page II-82.
Interesting.
Thank you for correcting me.
--
Grant. . . .
unix || die 
12:53 p.m.
On 07/09/2018 08:27 PM, Grant Taylor via cctalk wrote:
On 07/09/2018 11:58 AM, Al Kossow via cctalk wrote:
I'm actually the one who asked Al about this test hood. It seems like
it's a SCSI connector that connects the control lines to the data lines.
I've added some code which emulates this in software and the ROM said
'test hood connected' after the HP98265A message, and waited 1 minute on
boot. The 300 Test software also passed all checks. I'll verify that on
real hardware, and post the connections.
Regards
Sven
Someone working on simulating the scsi DIO board
in MAME asked me
about the scsi loopback test plug. Anyone ever seen one? Is it just
wires or are there active parts doing the loopback?
I've never heard of loopback related to SCSI.? I have seen many
external terminators that someone may miss-identify as a loopback
because it seems quite similar to a loopback for serial / parallel.
Is this by chance what they are talking about 
5:44 p.m.
On Mon, Jul 9, 2018 at 12:53 PM, Sven Schnelle via cctalk
<cctalk at classiccmp.org> wrote:
I'm actually the one who asked Al about this test hood. It seems like
it's a SCSI connector that connects the control lines to the data lines.
I've added some code which emulates this in software and the ROM said
'test hood connected' after the HP98265A message, and waited 1 minute on
boot. The 300 Test software also passed all checks. I'll verify that on
real hardware, and post the connections.
See also this manual on hpmuseum.net :
12016A_SCSIHostBusAdapterCard_InstallationAndReferenceManual_12016-90001_125pages_Dec92.pdf
http://www.hpmuseum.net/document.php?hwfile=4790
Page 7-7 (Page 76 of the PDF), Table 7-2. Loopback Test Panel Configuration
DATA0 <--> I/O
DATA1 <--> C/D
DATA2 <--> MSG
DATA3 <--> REQ
DATA4 <--> ACK
DATA5 <--> ATN
DATA6 <--> SEL
DATA7 <--> BSY
DATAP <--> RST
No idea if the HP 1000 A-Series 12016A SCSI interface would use the
same loopback connections, but it wouldn't surprise me if they did.
(The earlier Feb 91 second edition version of the 12016-90001 manual
on Bitsavers does include the DDL Diagnostic Program Chapter 7, which
has the Table 7-2. Loopback Test Panel Configuration)
6:17 p.m.
On Mon, Jul 9, 2018 at 5:44 PM, Glen Slick <glen.slick at gmail.com> wrote:
(The earlier Feb 91 second edition version of the 12016-90001 manual
on Bitsavers does include the DDL Diagnostic Program Chapter 7, which
has the Table 7-2. Loopback Test Panel Configuration)
I mean to type that the Feb 91 second edition version of the
12016-90001 manual does NOT include the DDL Diagnostic Program Chapter
7, that is why I referenced the Dec 92 third edition of the manual on
hpmuseum.net
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7 comments
5 participants
participants (5)
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aek＠bitsavers.org -
cctalk＠gtaylor.tnetconsulting.net -
ggs＠shiresoft.com -
glen.slick＠gmail.com -
svens＠stackframe.org