[Tfug] SCSI disks

[Bexley Hall]

--- John Karns <johnkarns at gmail.com> wrote:

> On 8/16/07, Bexley Hall <bexley401 at yahoo.com> wrote:
> > However, the LX uses "50 pin (SE) SCSI".  I've
> > never seen a 50 pin drive larger than 4G (but
> > I suspect they exist -- or existED!).  In any
> > case, I don't *have* such a device.
> >
> > *But*, I can probably find a *wide* SCSI drive
> > (non-SCA) of a larger size.
> 
> > But, is this as "simple" as getting a cable
> > with a 50 pin berg connector on one end and
> > a 68 pin wide scsi connector on the other?
> 
> Yes, I've done exactly that, connecting a 68-pin
> wide drive to an
> Adaptec 50-pin 1460 slim SCSI pcmcia card to read /
> write the drive.

Ah, OK.  But, how did you handle the termination on
the drive end of the cable?  ("Termination??  *What*
termination???  :>  )
 
> > I have just such a beast *but* I think it was
> > intended to go from a wide *host* to a narrow
> > *target* (i.e., there is a terminator on the
> > 50-pin end of the cable) -- not exactly what
> > I was looking for.
> >
> > Can I cut off the terminator (on the cable)
> > and, *if* the drive supports it, enable
> > termination on the drive?
> 
> I would say yes.  For me, for termination on the
> cable, I prefer a
> pluggable terminator anyway.  Aside: the 50 pin
> connectors, if you can
> find them anymore, are "instant install", in that
> they pierce the
> cable when pressed onto the cable, so you don't have
> to solder each
> connection.  This makes it practical to add a
> connector for a
> pluggable terminator, should you need it later on.

I have lots of IDC (e.g., Berg-style) connectors.
But, *my* problem is the cables that I have are

68W --------------- 50SE ----- terminator

I.e., they are expecting the "host" to be located
at the 68 pin end (with its on-board termination)
then, the narrow, SE drive on the 50 pin connector.
Finally, the terminator dangling off the end to
terminate the *drive* end of the cable.

I would cut off the terminator in my application
since that would be the "host" end of the cable
(and the host is already terminated).  *But*,
there is no way to "extend" the 68 pin end to tack
a terminator on there for the *drive* end of the
cable!  So, I would have to count on the drive
having termiation onboard, etc.  (I haven't looked
into this, yet)

> I found the SCSI specs are remarkably well thought
> out regarding maintaining backward compatibility.

Yes, though the standards have changed considerably
since their SASI origins.  :<  E.g., we don't deal
with "A" and "B" cables anymore... (thankfully)
 
> > Grrrr.... "Standards are great; everybody should
> > have one!"  :(
> 
> Hey, have you been talking to the MS people?  (OOXML
> vs ODF)  :)

<grin>


       
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