Can't see all 4 drives in quad-bay firewire enclosure

[itm]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

I have a quad-bay firewire IDE enclosure attached to an Athlon machine
running Windows XP SP2. I've tested drives in each of the 4 bays and
all appear to function correcty. The problem is that I can never get
more than 3 drives to be "seen" by the o/s at the same time.

There appear to be 2 IDE hosts in the unit. Here's what I've tried:
- If I connect 2 drives to Host 1 I can see both of them.
- If I connect 2 drives to Host 2 I can see both of them.
- If I connect 2 drives to Host 1 and 1 drive to Host 2 I can see all
3 drives
- If I connect 2 drives to Host 1 and 2 drives to Host 2 I can only
see 3 of the 4 drives.

So for example in the following configuration I can "see" drives A, B
and C:

Host 1: Drive A, Drive B
Host 2: Drive C

....but in the following configuration I can only see drives A, C and
D:

Host 1: Drive A, Drive B
Host 2: Drive C, Drive D

All four drives have been tested indivudually and are functional.

At the rear of the unit are 4 firewire ports (2 for each IDE host). I
have a cable connecting one of the ports on Host 1 to a port on Host 2
(I presume that this is correct, but don't actually know since the
documentation with the enclosure was pretty non-existent).

The drive is one of these:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW

Can anyone shed some light as to why I can never see all four drives
at the same time?

TIA for any help
Ian

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

There are two independent 1394-IDE bridge boards. I doubt they are the problem.

It probably has a 200W power supply, insufficient to spin up 4 drives at once.
Look at the 12V rating on the label.

"ITM" <nospam@ioxis.removethisbit.com> wrote in message
news:laqpe1tr2kr9m5sh7ncbm8avdsieh3hjin@4ax.com...
> I have a quad-bay firewire IDE enclosure attached to an Athlon machine
> running Windows XP SP2. I've tested drives in each of the 4 bays and
> all appear to function correcty. The problem is that I can never get
> more than 3 drives to be "seen" by the o/s at the same time.
>
[...]
>
> The drive is one of these:
> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW
>
> Can anyone shed some light as to why I can never see all four drives
> at the same time?
>

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

ITM wrote:

> I have a quad-bay firewire IDE enclosure attached to an Athlon machine
> running Windows XP SP2. I've tested drives in each of the 4 bays and
> all appear to function correcty. The problem is that I can never get
> more than 3 drives to be "seen" by the o/s at the same time.
>
> There appear to be 2 IDE hosts in the unit. Here's what I've tried:
> - If I connect 2 drives to Host 1 I can see both of them.
> - If I connect 2 drives to Host 2 I can see both of them.
> - If I connect 2 drives to Host 1 and 1 drive to Host 2 I can see all
> 3 drives
> - If I connect 2 drives to Host 1 and 2 drives to Host 2 I can only
> see 3 of the 4 drives.
>
> So for example in the following configuration I can "see" drives A, B
> and C:
>
> Host 1: Drive A, Drive B
> Host 2: Drive C
>
> ...but in the following configuration I can only see drives A, C and
> D:
>
> Host 1: Drive A, Drive B
> Host 2: Drive C, Drive D
>
> All four drives have been tested indivudually and are functional.
>
> At the rear of the unit are 4 firewire ports (2 for each IDE host). I
> have a cable connecting one of the ports on Host 1 to a port on Host 2
> (I presume that this is correct, but don't actually know since the
> documentation with the enclosure was pretty non-existent).
>
> The drive is one of these:
>
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW
>
> Can anyone shed some light as to why I can never see all four drives
> at the same time?

You might want to google the chip number, OXFW911--you'll find a lot of
products that use the same chip and one might have better documentation.
There's also a full datasheet on the Oxford semiconductor site but it
doesn't seem to be very helpful.

>
> TIA for any help
> Ian

--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

ITM <nospam@ioxis.removethisbit.com> wrote:

> I have a quad-bay firewire IDE enclosure attached to an Athlon machine
> running Windows XP SP2. I've tested drives in each of the 4 bays and
> all appear to function correcty. The problem is that I can never get
> more than 3 drives to be "seen" by the o/s at the same time.

> There appear to be 2 IDE hosts in the unit. Here's what I've tried:
> - If I connect 2 drives to Host 1 I can see both of them.
> - If I connect 2 drives to Host 2 I can see both of them.
> - If I connect 2 drives to Host 1 and 1 drive to Host 2 I can see all 3 drives
> - If I connect 2 drives to Host 1 and 2 drives to Host 2 I can only see 3 of
> the 4 drives.

You dont say anything about the actual drives themselves.

It may just be a pair that dont like coexisting on
one controller unless all 4 drives are identical etc.

> So for example in the following configuration I can "see" drives A, B and C:
>
> Host 1: Drive A, Drive B
> Host 2: Drive C

> ...but in the following configuration I can only see drives A, C and D:

> Host 1: Drive A, Drive B
> Host 2: Drive C, Drive D

> All four drives have been tested indivudually and are functional.

> At the rear of the unit are 4 firewire ports (2 for each IDE host).
> I have a cable connecting one of the ports on Host 1 to a port on
> Host 2 (I presume that this is correct, but don't actually know since
> the documentation with the enclosure was pretty non-existent).

> The drive is one of these:
> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW

> Can anyone shed some light as to why I can
> never see all four drives at the same time?

I'd test the coexistence on a single controller possibility.

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Eric Gisin <ericgisin@hotmail.com> wrote:

> There are two independent 1394-IDE bridge
> boards. I doubt they are the problem.
>
> It probably has a 200W power supply, insufficient to spin up 4 drives at once.

Bullshit 200W is.

> Look at the 12V rating on the label.


> "ITM" <nospam@ioxis.removethisbit.com> wrote in message
> news:laqpe1tr2kr9m5sh7ncbm8avdsieh3hjin@4ax.com...
>> I have a quad-bay firewire IDE enclosure attached to an Athlon
>> machine running Windows XP SP2. I've tested drives in each of the 4
>> bays and all appear to function correcty. The problem is that I can
>> never get more than 3 drives to be "seen" by the o/s at the same
>> time.
>>
> [...]
>>
>> The drive is one of these:
>> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW
>>
>> Can anyone shed some light as to why I can never see all four drives
>> at the same time?

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"Rod Speed" <rod_speed@yahoo.com> wrote in message news:3l4mbiF111j5hU1@individual.net...
> Eric Gisin <ericgisin@hotmail.com> wrote:
>
> > There are two independent 1394-IDE bridge
> > boards. I doubt they are the problem.
> >
> > It probably has a 200W power supply, insufficient to spin up 4 drives at once.
>
> Bullshit 200W is.
>
> > Look at the 12V rating on the label.

Ever seen a 200W ATX, Rodney?
The 5v and 12v are split, sufficient for small cases with 3 drive bays.

 

[itm]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

On Mon, 1 Aug 2005 04:01:47 +1000, "Rod Speed" <rod_speed@yahoo.com>
wrote:

>ITM <nospam@ioxis.removethisbit.com> wrote:
>
>> I have a quad-bay firewire IDE enclosure attached to an Athlon machine
>> running Windows XP SP2. I've tested drives in each of the 4 bays and
>> all appear to function correcty. The problem is that I can never get
>> more than 3 drives to be "seen" by the o/s at the same time.
>
>> There appear to be 2 IDE hosts in the unit. Here's what I've tried:
>> - If I connect 2 drives to Host 1 I can see both of them.
>> - If I connect 2 drives to Host 2 I can see both of them.
>> - If I connect 2 drives to Host 1 and 1 drive to Host 2 I can see all 3 drives
>> - If I connect 2 drives to Host 1 and 2 drives to Host 2 I can only see 3 of
>> the 4 drives.
>
>You dont say anything about the actual drives themselves.
>
>It may just be a pair that dont like coexisting on
>one controller unless all 4 drives are identical etc.
>
>> So for example in the following configuration I can "see" drives A, B and C:
>>
>> Host 1: Drive A, Drive B
>> Host 2: Drive C
>
>> ...but in the following configuration I can only see drives A, C and D:
>
>> Host 1: Drive A, Drive B
>> Host 2: Drive C, Drive D
>
>> All four drives have been tested indivudually and are functional.
>
>> At the rear of the unit are 4 firewire ports (2 for each IDE host).
>> I have a cable connecting one of the ports on Host 1 to a port on
>> Host 2 (I presume that this is correct, but don't actually know since
>> the documentation with the enclosure was pretty non-existent).
>
>> The drive is one of these:
>> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW
>
>> Can anyone shed some light as to why I can
>> never see all four drives at the same time?
>
>I'd test the coexistence on a single controller possibility.
>
I've switched the drives around, and found that A and B co-exist fine
until I add drive D to the 2nd host. Likewise C and D co-exist fine
when I don't have A and B installed.

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

ITM <nospam@ioxis.removethisbit.com> wrote
> Rod Speed <rod_speed@yahoo.com> wrote
>> ITM <nospam@ioxis.removethisbit.com> wrote

>>> I have a quad-bay firewire IDE enclosure attached to an Athlon
>>> machine running Windows XP SP2. I've tested drives in each of the
>>> 4 bays and all appear to function correcty. The problem is that I can
>>> never get more than 3 drives to be "seen" by the o/s at the same time.

>>> There appear to be 2 IDE hosts in the unit. Here's what I've tried:
>>> - If I connect 2 drives to Host 1 I can see both of them.
>>> - If I connect 2 drives to Host 2 I can see both of them.
>>> - If I connect 2 drives to Host 1 and 1 drive to Host 2 I can see all 3
>>> drives
>>> - If I connect 2 drives to Host 1 and 2 drives to Host 2 I can only see 3 of
>>> the 4 drives.

>> You dont say anything about the actual drives themselves.

>> It may just be a pair that dont like coexisting on
>> one controller unless all 4 drives are identical etc.

>>> So for example in the following configuration
>>> I can "see" drives A, B and C:

>>> Host 1: Drive A, Drive B
>>> Host 2: Drive C

>>> ...but in the following configuration
>>> I can only see drives A, C and D:

>>> Host 1: Drive A, Drive B
>>> Host 2: Drive C, Drive D

>>> All four drives have been tested indivudually and are functional.

>>> At the rear of the unit are 4 firewire ports (2 for each IDE host).
>>> I have a cable connecting one of the ports on Host 1 to a port
>>> on Host 2 (I presume that this is correct, but don't actually know
>>> since the documentation with the enclosure was pretty non-existent).

>>> The drive is one of these:
>>> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW

>>> Can anyone shed some light as to why I can
>>> never see all four drives at the same time?

>> I'd test the coexistence on a single controller possibility.

> I've switched the drives around, and found that A and B
> co-exist fine until I add drive D to the 2nd host. Likewise C
> and D co-exist fine when I don't have A and B installed.

OK, what is the story on the power supply in that box
and what is the detail on the actual drive you are putting
in the box. What are their model numbers and sizes ?

 

[itm]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

On Mon, 1 Aug 2005 18:57:29 +1000, "Rod Speed" <rod_speed@yahoo.com>
wrote:

>ITM <nospam@ioxis.removethisbit.com> wrote
>> Rod Speed <rod_speed@yahoo.com> wrote
>>> ITM <nospam@ioxis.removethisbit.com> wrote
>
>>>> I have a quad-bay firewire IDE enclosure attached to an Athlon
>>>> machine running Windows XP SP2. I've tested drives in each of the
>>>> 4 bays and all appear to function correcty. The problem is that I can
>>>> never get more than 3 drives to be "seen" by the o/s at the same time.
>
>>>> There appear to be 2 IDE hosts in the unit. Here's what I've tried:
>>>> - If I connect 2 drives to Host 1 I can see both of them.
>>>> - If I connect 2 drives to Host 2 I can see both of them.
>>>> - If I connect 2 drives to Host 1 and 1 drive to Host 2 I can see all 3
>>>> drives
>>>> - If I connect 2 drives to Host 1 and 2 drives to Host 2 I can only see 3 of
>>>> the 4 drives.
>
>>> You dont say anything about the actual drives themselves.
>
>>> It may just be a pair that dont like coexisting on
>>> one controller unless all 4 drives are identical etc.
>
>>>> So for example in the following configuration
>>>> I can "see" drives A, B and C:
>
>>>> Host 1: Drive A, Drive B
>>>> Host 2: Drive C
>
>>>> ...but in the following configuration
>>>> I can only see drives A, C and D:
>
>>>> Host 1: Drive A, Drive B
>>>> Host 2: Drive C, Drive D
>
>>>> All four drives have been tested indivudually and are functional.
>
>>>> At the rear of the unit are 4 firewire ports (2 for each IDE host).
>>>> I have a cable connecting one of the ports on Host 1 to a port
>>>> on Host 2 (I presume that this is correct, but don't actually know
>>>> since the documentation with the enclosure was pretty non-existent).
>
>>>> The drive is one of these:
>>>> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW
>
>>>> Can anyone shed some light as to why I can
>>>> never see all four drives at the same time?
>
>>> I'd test the coexistence on a single controller possibility.
>
>> I've switched the drives around, and found that A and B
>> co-exist fine until I add drive D to the 2nd host. Likewise C
>> and D co-exist fine when I don't have A and B installed.
>
>OK, what is the story on the power supply in that box
>and what is the detail on the actual drive you are putting
>in the box. What are their model numbers and sizes ?
>
The power supply is an Mapower 300w unit, model no PP-3007A.

The drives are:
Drive A: 200gb Maxtor Diamondmax Plus 9 YAR41VW0 ATA/133
Drive B: 400Gb Hitachi Deskstar HDS724040KLAT80
Drive C: 200gb Maxtor Diamondmax Plus 9 YAR41BW0 ATA/133
Drive D: 80Gb Maxtor 98196H8

I also have drive cooling fans on two of the drives, as they tend to
run extremely hot otherwise. Could these be pushing the power supply
to the limit??

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

ITM <nospam@ioxis.removethisbit.com> wrote:
> On Mon, 1 Aug 2005 18:57:29 +1000, "Rod Speed" <rod_speed@yahoo.com>
> wrote:
>
>> ITM <nospam@ioxis.removethisbit.com> wrote
>>> Rod Speed <rod_speed@yahoo.com> wrote
>>>> ITM <nospam@ioxis.removethisbit.com> wrote
>>
>>>>> I have a quad-bay firewire IDE enclosure attached to an Athlon
>>>>> machine running Windows XP SP2. I've tested drives in each of the
>>>>> 4 bays and all appear to function correcty. The problem is that
>>>>> I can never get more than 3 drives to be "seen" by the o/s at the
>>>>> same time.
>>
>>>>> There appear to be 2 IDE hosts in the unit. Here's what I've
>>>>> tried:
>>>>> - If I connect 2 drives to Host 1 I can see both of them.
>>>>> - If I connect 2 drives to Host 2 I can see both of them.
>>>>> - If I connect 2 drives to Host 1 and 1 drive to Host 2 I can see
>>>>> all 3 drives
>>>>> - If I connect 2 drives to Host 1 and 2 drives to Host 2 I can
>>>>> only see 3 of the 4 drives.
>>
>>>> You dont say anything about the actual drives themselves.
>>
>>>> It may just be a pair that dont like coexisting on
>>>> one controller unless all 4 drives are identical etc.
>>
>>>>> So for example in the following configuration
>>>>> I can "see" drives A, B and C:
>>
>>>>> Host 1: Drive A, Drive B
>>>>> Host 2: Drive C
>>
>>>>> ...but in the following configuration
>>>>> I can only see drives A, C and D:
>>
>>>>> Host 1: Drive A, Drive B
>>>>> Host 2: Drive C, Drive D
>>
>>>>> All four drives have been tested indivudually and are functional.
>>
>>>>> At the rear of the unit are 4 firewire ports (2 for each IDE
>>>>> host).
>>>>> I have a cable connecting one of the ports on Host 1 to a port
>>>>> on Host 2 (I presume that this is correct, but don't actually know
>>>>> since the documentation with the enclosure was pretty
>>>>> non-existent).
>>
>>>>> The drive is one of these:
>>>>> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW
>>
>>>>> Can anyone shed some light as to why I can
>>>>> never see all four drives at the same time?
>>
>>>> I'd test the coexistence on a single controller possibility.
>>
>>> I've switched the drives around, and found that A and B
>>> co-exist fine until I add drive D to the 2nd host. Likewise C
>>> and D co-exist fine when I don't have A and B installed.
>>
>> OK, what is the story on the power supply in that box
>> and what is the detail on the actual drive you are putting
>> in the box. What are their model numbers and sizes ?

> The power supply is an Mapower 300w unit, model no PP-3007A.

Should be fine to power the drives below.

> The drives are:
> Drive A: 200gb Maxtor Diamondmax Plus 9 YAR41VW0 ATA/133
> Drive B: 400Gb Hitachi Deskstar HDS724040KLAT80
> Drive C: 200gb Maxtor Diamondmax Plus 9 YAR41BW0 ATA/133
> Drive D: 80Gb Maxtor 98196H8

> I also have drive cooling fans on two of the drives,
> as they tend to run extremely hot otherwise. Could
> these be pushing the power supply to the limit??

Nar, shouldnt be a problem.

Cant you measure the power supply output voltages with a multimeter ?

The most likely possibility is a bad power supply.

 

[itm]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

On Tue, 2 Aug 2005 06:06:02 +1000, "Rod Speed" <rod_speed@yahoo.com>
wrote:

>ITM <nospam@ioxis.removethisbit.com> wrote:
>> On Mon, 1 Aug 2005 18:57:29 +1000, "Rod Speed" <rod_speed@yahoo.com>
>> wrote:
>>
>>> ITM <nospam@ioxis.removethisbit.com> wrote
>>>> Rod Speed <rod_speed@yahoo.com> wrote
>>>>> ITM <nospam@ioxis.removethisbit.com> wrote
>>>
>>>>>> I have a quad-bay firewire IDE enclosure attached to an Athlon
>>>>>> machine running Windows XP SP2. I've tested drives in each of the
>>>>>> 4 bays and all appear to function correcty. The problem is that
>>>>>> I can never get more than 3 drives to be "seen" by the o/s at the
>>>>>> same time.
>>>
>>>>>> There appear to be 2 IDE hosts in the unit. Here's what I've
>>>>>> tried:
>>>>>> - If I connect 2 drives to Host 1 I can see both of them.
>>>>>> - If I connect 2 drives to Host 2 I can see both of them.
>>>>>> - If I connect 2 drives to Host 1 and 1 drive to Host 2 I can see
>>>>>> all 3 drives
>>>>>> - If I connect 2 drives to Host 1 and 2 drives to Host 2 I can
>>>>>> only see 3 of the 4 drives.
>>>
>>>>> You dont say anything about the actual drives themselves.
>>>
>>>>> It may just be a pair that dont like coexisting on
>>>>> one controller unless all 4 drives are identical etc.
>>>
>>>>>> So for example in the following configuration
>>>>>> I can "see" drives A, B and C:
>>>
>>>>>> Host 1: Drive A, Drive B
>>>>>> Host 2: Drive C
>>>
>>>>>> ...but in the following configuration
>>>>>> I can only see drives A, C and D:
>>>
>>>>>> Host 1: Drive A, Drive B
>>>>>> Host 2: Drive C, Drive D
>>>
>>>>>> All four drives have been tested indivudually and are functional.
>>>
>>>>>> At the rear of the unit are 4 firewire ports (2 for each IDE
>>>>>> host).
>>>>>> I have a cable connecting one of the ports on Host 1 to a port
>>>>>> on Host 2 (I presume that this is correct, but don't actually know
>>>>>> since the documentation with the enclosure was pretty
>>>>>> non-existent).
>>>
>>>>>> The drive is one of these:
>>>>>> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW
>>>
>>>>>> Can anyone shed some light as to why I can
>>>>>> never see all four drives at the same time?
>>>
>>>>> I'd test the coexistence on a single controller possibility.
>>>
>>>> I've switched the drives around, and found that A and B
>>>> co-exist fine until I add drive D to the 2nd host. Likewise C
>>>> and D co-exist fine when I don't have A and B installed.
>>>
>>> OK, what is the story on the power supply in that box
>>> and what is the detail on the actual drive you are putting
>>> in the box. What are their model numbers and sizes ?
>
>> The power supply is an Mapower 300w unit, model no PP-3007A.
>
>Should be fine to power the drives below.
>
>> The drives are:
>> Drive A: 200gb Maxtor Diamondmax Plus 9 YAR41VW0 ATA/133
>> Drive B: 400Gb Hitachi Deskstar HDS724040KLAT80
>> Drive C: 200gb Maxtor Diamondmax Plus 9 YAR41BW0 ATA/133
>> Drive D: 80Gb Maxtor 98196H8
>
>> I also have drive cooling fans on two of the drives,
>> as they tend to run extremely hot otherwise. Could
>> these be pushing the power supply to the limit??
>
>Nar, shouldnt be a problem.
>
>Cant you measure the power supply output voltages with a multimeter ?
>
>The most likely possibility is a bad power supply.
>
Thanks Rod - it seems like you were spot-on. I've used a supplementary
power supply for the 4th drive and now I can see all four!

I don't know whether the original PSU was faulty, or whether it's just
a poorly specified/designed unit. Maybe I'll run it by the eBay seller
and see what he has to say.....

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

ITM <nospam@ioxis.removethisbit.com> wrote:
> On Tue, 2 Aug 2005 06:06:02 +1000, "Rod Speed" <rod_speed@yahoo.com>
> wrote:
>
>> ITM <nospam@ioxis.removethisbit.com> wrote:
>>> On Mon, 1 Aug 2005 18:57:29 +1000, "Rod Speed" <rod_speed@yahoo.com>
>>> wrote:
>>>
>>>> ITM <nospam@ioxis.removethisbit.com> wrote
>>>>> Rod Speed <rod_speed@yahoo.com> wrote
>>>>>> ITM <nospam@ioxis.removethisbit.com> wrote
>>>>
>>>>>>> I have a quad-bay firewire IDE enclosure attached to an Athlon
>>>>>>> machine running Windows XP SP2. I've tested drives in each of
>>>>>>> the 4 bays and all appear to function correcty. The problem is
>>>>>>> that I can never get more than 3 drives to be "seen" by the o/s
>>>>>>> at the same time.
>>>>
>>>>>>> There appear to be 2 IDE hosts in the unit. Here's what I've
>>>>>>> tried:
>>>>>>> - If I connect 2 drives to Host 1 I can see both of them.
>>>>>>> - If I connect 2 drives to Host 2 I can see both of them.
>>>>>>> - If I connect 2 drives to Host 1 and 1 drive to Host 2 I can
>>>>>>> see all 3 drives
>>>>>>> - If I connect 2 drives to Host 1 and 2 drives to Host 2 I can
>>>>>>> only see 3 of the 4 drives.
>>>>
>>>>>> You dont say anything about the actual drives themselves.
>>>>
>>>>>> It may just be a pair that dont like coexisting on
>>>>>> one controller unless all 4 drives are identical etc.
>>>>
>>>>>>> So for example in the following configuration
>>>>>>> I can "see" drives A, B and C:
>>>>
>>>>>>> Host 1: Drive A, Drive B
>>>>>>> Host 2: Drive C
>>>>
>>>>>>> ...but in the following configuration
>>>>>>> I can only see drives A, C and D:
>>>>
>>>>>>> Host 1: Drive A, Drive B
>>>>>>> Host 2: Drive C, Drive D
>>>>
>>>>>>> All four drives have been tested indivudually and are
>>>>>>> functional.
>>>>
>>>>>>> At the rear of the unit are 4 firewire ports (2 for each IDE
>>>>>>> host).
>>>>>>> I have a cable connecting one of the ports on Host 1 to a port
>>>>>>> on Host 2 (I presume that this is correct, but don't actually
>>>>>>> know since the documentation with the enclosure was pretty
>>>>>>> non-existent).
>>>>
>>>>>>> The drive is one of these:
>>>>>>> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=167&item=5224421983&rd=1&ssPageName=WDVW
>>>>
>>>>>>> Can anyone shed some light as to why I can
>>>>>>> never see all four drives at the same time?
>>>>
>>>>>> I'd test the coexistence on a single controller possibility.
>>>>
>>>>> I've switched the drives around, and found that A and B
>>>>> co-exist fine until I add drive D to the 2nd host. Likewise C
>>>>> and D co-exist fine when I don't have A and B installed.
>>>>
>>>> OK, what is the story on the power supply in that box
>>>> and what is the detail on the actual drive you are putting
>>>> in the box. What are their model numbers and sizes ?
>>
>>> The power supply is an Mapower 300w unit, model no PP-3007A.
>>
>> Should be fine to power the drives below.
>>
>>> The drives are:
>>> Drive A: 200gb Maxtor Diamondmax Plus 9 YAR41VW0 ATA/133
>>> Drive B: 400Gb Hitachi Deskstar HDS724040KLAT80
>>> Drive C: 200gb Maxtor Diamondmax Plus 9 YAR41BW0 ATA/133
>>> Drive D: 80Gb Maxtor 98196H8
>>
>>> I also have drive cooling fans on two of the drives,
>>> as they tend to run extremely hot otherwise. Could
>>> these be pushing the power supply to the limit??
>>
>> Nar, shouldnt be a problem.
>>
>> Cant you measure the power supply output voltages with a multimeter ?
>>
>> The most likely possibility is a bad power supply.

> Thanks Rod - it seems like you were spot-on. I've used a supplementary
> power supply for the 4th drive and now I can see all four!

Great.

> I don't know whether the original PSU was faulty,
> or whether it's just a poorly specified/designed unit.

300W should be plenty. It might conceivably be some
dinosaur that is left over from the pre P4 and AMD days which
is a bit lacking in the 12V capability, but thats not that likely.

A fault is more likely in my opinion.

> Maybe I'll run it by the eBay seller and see what he has to say.....

Yeah, I would, since it basically doesnt do what it was claimed to do.