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| Author |
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Guest
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 Posted: Tue Sep 19, 2006 1:56 pm Post subject: Compaq SCSI drives, Convertors and AHA-2940 PCI cards HELP?? |
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Hi All,
Have Googled a lot but with no definitive answer.
I have a PCI AHA-2940 SCSI card, with a three (plus the one on the
board) connector lead (the lead is 50 pin). I have also acquired three
Compaq 9.1 GB Wide Ultra Scsi3 Drives, model number HB00931893. These
are in caddies. I have removed one from the caddy and noted (what
appears to be) the 80 pin mini centronics looking connector opn the
back of the drive.
Now I have looked at the cable converters for 50 pin to 68/80 pin, but
these
(http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290031264429)
appear not to be right.
1) Do I need a cable from the connector board to the SCSI drive as well
or does the board plug straight on to the back of the drive?
2) Do the Compaq SCSI's have a proprietary connector?
3) The technical spec. for the card states that you can connect 7
drives to it, can I therefore connect three of these drives to the
three individual connectors on the cable?
4) If yes, do I need to consider master/slave setting like I do with
IDE drives?
This is going into a desktop PC I'm going to stick on the router at
home to share files.
Many thanks for any help.
ST |
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Michael Baeuerle
Guest
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| Posted: Tue Sep 19, 2006 9:12 pm Post subject: Re: Compaq SCSI drives, Convertors and AHA-2940 PCI cards HE |
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tvr390@hotmail.com wrote:
| Quote: |
Hi All,
Have Googled a lot but with no definitive answer.
I have a PCI AHA-2940 SCSI card, with a three (plus the one on the
board) connector lead (the lead is 50 pin). I have also acquired three
Compaq 9.1 GB Wide Ultra Scsi3 Drives, model number HB00931893. These
are in caddies. I have removed one from the caddy and noted (what
appears to be) the 80 pin mini centronics looking connector opn the
back of the drive.
|
The 80Pin Centronics-like connectors are called "SCA". Drives with such
a connector have no Molex 4Pin power connector because power is supplied
via the SCA connector.
| Quote: | Now I have looked at the cable converters for 50 pin to 68/80 pin, but
these
(http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290031264429)
appear not to be right.
|
This one should work. The SCA connector is the one on the top picture.
| Quote: | 1) Do I need a cable from the connector board to the SCSI drive as well
or does the board plug straight on to the back of the drive?
|
No, the converter board should fit directly to the drive. As you can see
it provides a power connector, configuration jumpers (for the SCSI ID,
motor start options and a Busy-LED) and two data bus connectors: One for
a narrow bus (50Pin) and one for a wide bus (68Pin).
You should never use the 50Pin narrow bus connector if your drive
supports wide bus (like yours do as you stated above) because this
converter board provides no terminator for the unused bus lines in this
case. Floating bus lines can cause strange misbehaviour.
| Quote: | 2) Do the Compaq SCSI's have a proprietary connector?
|
Unlikely, proprietary connectors are not common for SCSI disks.
Compaq have not manufactured disks, it should be a OEM model from one of
the well known companies. Check if there are more numbers on the disks,
e.g. "STx9xxxWC/LC" for 9GB Seagate disks with SCA connector.
| Quote: | 3) The technical spec. for the card states that you can connect 7
drives to it, can I therefore connect three of these drives to the
three individual connectors on the cable?
|
Yes, you can connect up to 7 disks to a narrow bus (50Pin) and up to 15
disks to a wide bus (68Pin). But you should really use a 68Pin cable for
your wide SCSI drives. Additionally you need a terminator on each end of
the bus. The AHA-2940 have one onboard that can be enabled with the
setup tool (Ctrl-A at boot). The second one must be on the other end of
the cable.
I recommend buying a 68Pin cable with a terminator already mounted on
one end for this case.
| Quote: | 4) If yes, do I need to consider master/slave setting like I do with
IDE drives?
|
Yes. The addresses of SCSI devices are called "IDs", IDs above 7 are
only valid for wide SCSI. They are normally configured with the jumpers
on the converter board for SCA disks. Every disk on a bus must have a
unique ID. Dont't use ID 7 for the disks because this is the default ID
for the AHA-2940.
Micha |
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Folkert Rienstra
Guest
|
| Posted: Wed Sep 20, 2006 12:09 am Post subject: Re: Compaq SCSI drives, Convertors and AHA-2940 PCI cards HE |
|
|
"Michael Baeuerle" <michael.baeuerle@stz-e.de> wrote in message news:fgh5u3-viu.ln1@micha.freeshell.org
| Quote: | tvr390@hotmail.com wrote:
Hi All,
Have Googled a lot but with no definitive answer.
I have a PCI AHA-2940 SCSI card, with a three (plus the one on the
board) connector lead (the lead is 50 pin). I have also acquired three
Compaq 9.1 GB Wide Ultra Scsi3 Drives, model number HB00931893. These
are in caddies. I have removed one from the caddy and noted (what
appears to be) the 80 pin mini centronics looking connector opn the
back of the drive.
The 80Pin Centronics-like connectors are called "SCA". Drives with such
a connector have no Molex 4Pin power connector because power is supplied
via the SCA connector.
Now I have looked at the cable converters for 50 pin to 68/80 pin, but
these
(http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290031264429)
appear not to be right.
This one should work. The SCA connector is the one on the top picture.
1) Do I need a cable from the connector board to the SCSI drive as well
or does the board plug straight on to the back of the drive?
No, the converter board should fit directly to the drive. As you can see
it provides a power connector, configuration jumpers (for the SCSI ID,
motor start options and a Busy-LED) and two data bus connectors:
One for a narrow bus (50Pin) and one for a wide bus (68Pin).
You should never use the 50Pin narrow bus connector if your drive
supports wide bus (like yours do as you stated above) because this
converter board provides no terminator for the unused bus lines in
this case.
|
Well, that's not the whole story. You can use the the 50-pin connector
and cable but you have to provide a wide terminator to the 68-pin con-
nector in that case. That would be an external one or a special internal
one (that fits on a device connector instead of a cable connector).
| Quote: | Floating bus lines can cause strange misbehaviour.
|
Actually, a lot of drives won't even initialize with the upper byte lines
left floating (not biased by termination).
| Quote: |
2) Do the Compaq SCSI's have a proprietary connector?
Unlikely, proprietary connectors are not common for SCSI disks.
Compaq have not manufactured disks, it should be a OEM model from one of
the well known companies. Check if there are more numbers on the disks,
e.g. "STx9xxxWC/LC" for 9GB Seagate disks with SCA connector.
3) The technical spec. for the card states that you can connect 7
drives to it, can I therefore connect three of these drives to the
three individual connectors on the cable?
Yes, you can connect up to 7 disks to a narrow bus (50Pin) and up to 15
disks to a wide bus (68Pin).
But you should really use a 68-Pin cable for your wide SCSI drives.
|
Well, that requires a 50->68-pin convertor on the SCSI controller.
The key point is the termination, not the cable, see above.
| Quote: | Additionally you need a terminator on each end of the bus.
The AHA-2940 have one onboard that can be enabled with the setup
tool (Ctrl-A at boot). The second one must be on the other end of
the cable.
I recommend buying a 68Pin cable with a terminator already mounted on
one end for this case.
|
And a 50->68-pin convertor obviously.
| Quote: |
4) If yes, do I need to consider master/slave setting like I do with
IDE drives?
Yes. The addresses of SCSI devices are called "IDs", IDs above 7 are
only valid for wide SCSI. They are normally configured with the jumpers
on the converter board for SCA disks. Every disk on a bus must have a
unique ID. Dont't use ID 7 for the disks because this is the default ID
for the AHA-2940.
Micha |
|
|
| Back to top |
|
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Folkert Rienstra
Guest
|
| Posted: Wed Sep 20, 2006 12:09 am Post subject: Re: Compaq SCSI drives, Convertors and AHA-2940 PCI cards HE |
|
|
<tvr390@hotmail.com> wrote in message news:1158669590.798099.245650@i3g2000cwc.googlegroups.com
| Quote: | Hi All,
Have Googled a lot but with no definitive answer.
I have a PCI AHA-2940 SCSI card, with a three (plus the one on the
board) connector lead (the lead is 50 pin). I have also acquired three
Compaq 9.1 GB Wide Ultra Scsi3 Drives, model number HB00931893.
These are in caddies. I have removed one from the caddy and noted
(what appears to be) the 80 pin mini centronics looking connector on the
back of the drive.
Now I have looked at the cable converters for 50 pin to 68/80 pin, but
these
(http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290031264429)
appear not to be right.
|
No? What's wrong with it exactly?
| Quote: |
1) Do I need a cable from the connector board to the SCSI drive as well
or does the board plug straight on to the back of the drive?
|
Here's a question for you:
What do you expect a removable drive caddy to plug in to?
| Quote: |
2) Do the Compaq SCSI's have a proprietary connector?
|
Yes, and so do all drives for use in backplanes.
| Quote: | 3) The technical spec. for the card states that you can connect 7
drives to it, can I therefore connect three of these drives to the
three individual connectors on the cable?
|
Here's a question for you: Any other way to connect 7 devices?
| Quote: | 4) If yes, do I need to consider master/slave setting like I do with
IDE drives?
|
Here's a question for you: how many choices in Master and Slave?
| Quote: |
This is going into a desktop PC I'm going to stick on the router at
home to share files.
Many thanks for any help.
ST |
|
|
| Back to top |
|
|
Michael Baeuerle
Guest
|
| Posted: Thu Sep 21, 2006 1:30 am Post subject: Re: Compaq SCSI drives, Convertors and AHA-2940 PCI cards HE |
|
|
Folkert Rienstra wrote:
| Quote: |
Michael Baeuerle wrote:
tvr390@hotmail.com wrote:
[...]
1) Do I need a cable from the connector board to the SCSI drive as well
or does the board plug straight on to the back of the drive?
No, the converter board should fit directly to the drive. As you can see
it provides a power connector, configuration jumpers (for the SCSI ID,
motor start options and a Busy-LED) and two data bus connectors:
One for a narrow bus (50Pin) and one for a wide bus (68Pin).
You should never use the 50Pin narrow bus connector if your drive
supports wide bus (like yours do as you stated above) because this
converter board provides no terminator for the unused bus lines in
this case.
Well, that's not the whole story. You can use the the 50-pin connector
and cable but you have to provide a wide terminator to the 68-pin con-
nector in that case. That would be an external one or a special internal
one (that fits on a device connector instead of a cable connector).
|
This is only possible for a single disk at the end of the cable, but the
OP wants to connect 3 such disks.
| Quote: | Floating bus lines can cause strange misbehaviour.
Actually, a lot of drives won't even initialize with the upper byte lines
left floating (not biased by termination).
|
One of them is the IBM DFHS (I have soldered discrete resistors to the
converter board to form a "high-only" terminator to get my DFHS running
in the middle of a narrow bus).
| Quote: | [...]
But you should really use a 68-Pin cable for your wide SCSI drives.
Well, that requires a 50->68-pin convertor on the SCSI controller.
|
Argh, I assumed an AHA-2940W. But you are right, it's the narrow model.
| Quote: | The key point is the termination, not the cable, see above.
|
OK, but nevertheless it should be easier with the 68Pin cable: One
80/68Pin-converter for every disk and one 50/68Pin converter for the
hostadapter. In this case a single wide terminator on the end of the
cable then will additionally bias all unused lines on all disks.
With a 50Pin cable you need the ugly "high-only" terminators on the
converters for at least 2 of the 3 disks. More complicated and not
cheaper ...
| Quote: | Additionally you need a terminator on each end of the bus.
The AHA-2940 have one onboard that can be enabled with the setup
tool (Ctrl-A at boot). The second one must be on the other end of
the cable.
I recommend buying a 68Pin cable with a terminator already mounted on
one end for this case.
And a 50->68-pin convertor obviously.
|
Yes. A cheap one without terminator will be sufficient.
Micha
--
http:/micha.freeshell.org |
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Folkert Rienstra
Guest
|
| Posted: Thu Sep 21, 2006 3:26 am Post subject: Re: Compaq SCSI drives, Convertors and AHA-2940 PCI cards HE |
|
|
"Michael Baeuerle" <michael.baeuerle@gmx.net> wrote in message news:cll8u3-f81.ln1@micha.freeshell.org
| Quote: | Folkert Rienstra wrote:
Michael Baeuerle wrote:
tvr390@hotmail.com wrote:
[...]
1) Do I need a cable from the connector board to the SCSI drive as well
or does the board plug straight on to the back of the drive?
No, the converter board should fit directly to the drive. As you can see
it provides a power connector, configuration jumpers (for the SCSI ID,
motor start options and a Busy-LED) and two data bus connectors:
One for a narrow bus (50Pin) and one for a wide bus (68Pin).
You should never use the 50Pin narrow bus connector if your drive
supports wide bus (like yours do as you stated above) because this
converter board provides no terminator for the unused bus lines in
this case.
Well, that's not the whole story. You can use the the 50-pin connector
and cable but you have to provide a wide terminator to the 68-pin con-
nector in that case. That would be an external one or a special internal
one (that fits on a device connector instead of a cable connector).
This is only possible for a single disk at the end of the cable,
but the OP wants to connect 3 such disks.
|
Correct, missed that.
| Quote: |
Floating bus lines can cause strange misbehaviour.
Actually, a lot of drives won't even initialize with the upper byte lines
left floating (not biased by termination).
One of them is the IBM DFHS (I have soldered discrete resistors to the
converter board to form a "high-only" terminator to get my DFHS running
in the middle of a narrow bus).
|
Funny that, I once did the same to a 50->68-pin converter for exactly that drive.
Used only 1 resistor though, tied to all 9 lines.
| Quote: |
[...]
But you should really use a 68-Pin cable for your wide SCSI drives.
Well, that requires a 50->68-pin convertor on the SCSI controller.
Argh, I assumed an AHA-2940W. But you are right, it's the narrow model.
The key point is the termination, not the cable, see above.
OK, but nevertheless it should be easier with the 68Pin cable: One
80/68Pin-converter for every disk and one 50/68Pin converter for the
hostadapter. In this case a single wide terminator on the end of the
cable then will additionally bias all unused lines on all disks.
|
Agree.
| Quote: |
With a 50Pin cable you need the ugly "high-only" terminators on the
converters for at least 2 of the 3 disks.
More complicated and not cheaper ...
|
In theory. Sometime practice defies theory, especially on Ebay.
| Quote: |
Additionally you need a terminator on each end of the bus.
The AHA-2940 have one onboard that can be enabled with the setup
tool (Ctrl-A at boot). The second one must be on the other end of
the cable.
I recommend buying a 68Pin cable with a terminator already mounted on
one end for this case.
And a 50->68-pin convertor obviously.
Yes. A cheap one without terminator will be sufficient.
Micha |
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