[RndTbl] SCSI cable length

[Adam Thompson]

IIRC the xx4x were bootable, the xx2x were not.
I don't recall what other differences there were, but the 2920 had a dramatically simpler PCB.
-Adam

On July 3, 2015 9:28:26 PM CDT, Hartmut W Sager <hwsager at marityme.net> wrote:
>Oops, I may have gotten something wrong.  Web information suggests that
>the
>AHA-2920 series cards are also bus-mastering, in which case, I can't
>remember what's different between AHA-2920 and AHA-2940.  But I do
>remember
>that I used a lot of AHA-2940 series cards.
>
>Hartmut W Sager - Tel +1-204-339-8331, +1-204-515-1701, +1-204-515-1700
>
>
>On 3 July 2015 at 21:16, Hartmut W Sager <hwsager at marityme.net> wrote:
>
>> Two of the most famous single-ended classic SCSI-2 host adapters of
>that
>> era, using this 50-pin dense connector, were the Adaptec AHA-2920
>> non-bus-mastering series and the Adaptec AHA-2940 bus-mastering
>series, for
>> PCI slot motherboards.  They also sported an internal 50-pin 2-row
>ribbon
>> connector for internal SCSI drives (and a 34-pin 2-row ribbon
>connector for
>> floppy drives in the case of the AHA-2922 and AHA-2942, I think).
>>
>> You could actually have both internal and external devices on the
>single
>> SCSI chain (card in the middle), as long as you disabled the
>terminating
>> resistor pack on the card itself.  You then had to be especially
>careful in
>> deciding which card/device would supply the terminating resistor
>power.  I
>> recall that Fujitsu hard drives were exceptionally problematic in
>these
>> configurations.
>>
>> I presume you (Trevor) know all about having to set each SCSI
>> drive/device, including the host adapter, to a unique SCSI ID, yes?
>>
>> Life with SATA and USB really is more pleasant.
>>
>> Hartmut W Sager - Tel +1-204-339-8331, +1-204-515-1701,
>+1-204-515-1700
>>
>>
>> On 3 July 2015 at 19:48, Hartmut W Sager <hwsager at marityme.net>
>wrote:
>>
>>> > I'm a big SCSI guy, but ...
>>>
>>> I too am an old SCSI fan, but my interest started to wane when so
>many
>>> SCSI signalling standards and connectors began to proliferate
>together with
>>> SCSI moving totally into the high-end server realm and away from
>"ordinary"
>>> peripherals.  Oh, and then there was that "termination power"
>headache
>>> (usually selected/deselected by jumpers).
>>>
>>> > The device has a standard dense 50-pin 2-row connector.  I thought
>at
>>> first that meant for sure LVD, but now I'm thinking it just means
>ultra.
>>>
>>> It doesn't even mean "ultra", let alone HVD/LVD.  That connector
>became
>>> the norm during the single-ended classic SCSI 2 generation - to my
>great
>>> chagrin, since the Centronics 50-pin connector was so much better.
>>>
>>> > Is there a way to know what signalling this device uses based just
>on
>>> the connector?
>>>
>>> No, but:
>>>
>>> > I checked all available interent specs, incl the original manual,
>for
>>> the device and *nothing* specifies anything other than "SCSI".
>>>
>>> Since the original manual (lucky you to have that!) doesn't specify
>>> anything other than "SCSI", it is a near certainty that this isn't
>LVD or
>>> HVD, but simply good old single-ended classic SCSI (of at least SCSI
>2
>>> generation).  It probably isn't "ultra" either, especially if it's a
>>> scanner or CD drive or similar slow device rather than a hard drive.
>>>
>>> Hartmut W Sager - Tel +1-204-339-8331, +1-204-515-1701,
>+1-204-515-1700
>>>
>>>
>>> On 3 July 2015 at 16:06, Trevor Cordes <trevor at tecnopolis.ca> wrote:
>>>
>>>> I have an external SCSI device that I'd like to plug in on a 10-15'
>>>> cable.
>>>> The device has a standard dense 50-pin 2-row connector.  I thought
>at
>>>> first that meant for sure LVD, but now I'm thinking it just means
>ultra.
>>>> I need LVD to get over 1.5M cable length, according to spec.  LVD
>lets me
>>>> go to 12M it appears.  If it's just ultra then I'm SOL, I guess.
>>>>
>>>> Is there a way to know what signalling this device uses based just
>on the
>>>> connector?  I checked all available interent specs, incl the
>original
>>>> manual, for the device and *nothing* specifies anything other than
>>>> "SCSI".
>>>>
>>>> I'm a big SCSI guy, but my memory on the subject is starting to get
>>>> hazy due to disuse...
>>>> _______________________________________________
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>>>> Roundtable at muug.mb.ca
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>>>>
>>>
>>>
>>
>
>
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