[Tfug] SCSI disks

[Bexley Hall]

--- johngalt1 <johngalt1 at uswest.net> wrote:

> IMHO this problem / thread is way too complicated.
> Granted, the topic can be pain in the ass.

Simple problems are hardly worth thinking about!  :>
 
> IIRC, the problem was find a SCSi drive to fit a 50
> pin 8bit narrow SCSI host adapter. Correct?

Yes, though there are also mechanical constraints
that make your adapter solution (below) probably
impractical (most adapters taht I have found add a
fraction of an inch to the length of the drive;
Sun lunch boxen don't have much wiggle room  :< )
 
> I have / had some SCA drive adapters that had
> connectors to attach 50 pin and 68 pin cables to.
> Also, IIRC the adapters had places for terminating
> resistors. Elliott had such things, (or was it, 
> Frys in phoenix?) Nevertheless, one can

I can try Elliot's next time I am down that way.
A drive to feenigs is out of the question (I can
get a whole new *machine* for less than the cost
of gas  :> )

> get cheap ($15) SCA adapters that make this problem
> easier
> than trying many of the alternatives, IMO. (think
> mail order)

I suspect SCA adapters will *not* fit -- given the
current size of the connector shell which would
then be "extended" by the height of the mating Berg
connector, etc.

> narrow SCSI drives are getting scarce due to their
> age, but
> one can find lots of cheap SCA drives. IMHO, one can
> use
> such a drive in a narrow 8 bit HBA application. Just
> terminate it appropriately.

That is the essence of the problem!  :>
 
> I used to toy with putting connectors on ribbon
> cables, but often that turned out to work poorly 
> in the long run. At first I used pliers to squeeze
> the connector on to the cable. And after that 
> didn't work reliably, I used a smooth
> jawed vice, which didn't consistently work well

I have a "press" for that sort of thing (I often have
to make wiring harnesses for prototypes that I build;
way too pricey to farm out "Quantity 1" production  :>

> either. I used to do manufacture of aircraft grade
> connectors and wire harnesses, but somehow attaching
> connectors to 'simple ribbon cables' was beyond me
> at times. (my excuse is that brand X taiwan
> connector applicability isn't guaranteed with
> brand Z ribbon cable)

Aircraft/mil connectors are usually much larger
and ruggeder (is that even a word?).  And, they don't
*melt* when you leave a soldering iron on a pin
"a triffle too long"  :>

I've a lot of experience with ribbon cable connectors
as a firm I worked at had the (smart?) idea that
COTS cable (ribbon) plus COTS gold-plated connectors
(IDC Berg's) were a much more reliable approach than
laying out a circuit board (i.e. backplane) to
connect boards together.  You'd be amazed how many
products we built and shipped with that technology
(everything from medical instruments to gas pumps!).

Of course, in those applications, the cable isn't
dicked with like it is in a "hobbyist" computer!  :>



       
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