non-SCSI disks on a SCSI disk interface (was Re: Space, the next frontier) - test-drb@ccmp.vtda.org

26 May 1999

Well . . . I'd really never considered using an SMD <=>SCSI bridge.  I used
to have a CDC LARK drive on my CP/M system because I've always loved
removable media.  That was back when my elder son wasn't tall enough to get
on the table, though.   Now I use SCSI drives in trays.  All of them are 1GB
3.5" drives.  The frames are set to hold the device ID, so the drives are,
by the grace of God, hot-swappable.  Those little frame/tray combo's cost
$15!  It's the best $15 I've spent, for sure!

I was aware of the ESDI drives, having used a number, and having them around
the house as doorstops, etc.  The most interesting ones are the 380 MB size,
which, in both MINISCRIBE and MAXTOR incarnations, allow their converson
...
 from ESDI to SCSI with the swap of a single board.

Complete software packages, e.g. FPGA/CPLD support software from
conceptualization to programming tools want more than that, particularly if
you want schematic entry software with it.  I find 1GB about right.
Libraries can be left on the server unless they need to travel to a client's
site.

I fought quite a bit with the MAXTOR 1140's.  They just didn't work reliably
with RLL/ERLL encoding, though they were rock solid when used with MFM.  I
don't know why this was . . . I bought two of these babies about ten years
ago for use with a PERSTOR (remember them?) only to find that the controller
and drives didn't like each other.

My system drives ( also removable ) are EIDE models.  I saw 10.5 GB drives
for $199 (new) at Costco this morning.  I'm sure one can do better, but that
certainly would discourage me from paying $150 for used SCSI drives.  I
guess I am just too frugal . . .

Dick

-----Original Message-----
From: CLASSICCMP(a)trailing-edge.com &lt;CLASSICCMP(a)trailing-edge.com&gt;
To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
Date: Wednesday, May 26, 1999 6:27 PM
Subject: Re: non-SCSI disks on a SCSI disk interface (was Re: Space, the
next frontier)

...
  I've had
decent results with the ADAPTEC 4070's too.  What I'm mainly
interested in is having a boxed drive, in this case, complete with bridge
controller, which moves from system to system, as I do with my native SCSI
drives.  Unfortunately, there aren't any MFM/RLL drives big enough to be
interesting. 
Someone should correct me if I'm wrong (I'd be interested in knowing that
I'm wrong!), but the largest capacity MFM geometry is that of the Maxtor
XT2190 (1024 cylinders * 15 heads), giving you just under 150 Mbytes (M=10**6)
...
 after formatting at 19 sectors/track.  And the RLL
version gets
another 30% or so of capacity.

Hitachi ESDI drives are available up to 1.5Gbytes or so, and work well on
Emulex ESDI<->SCSI controller.

All the above was assuming you meant size=capacity.  If you meant
size=cubic feet or pounds, I'm sure you could put a 14" CDC SMD drive
on the other side of a SMD<->SCSI controller.

Of course, large embedded-controller SCSI drives are readily available on the
...
 surplus market these days.  9 Gbyte drives start below
$150.00, and
2 Gbyte drives seem to get around $40.

--
 Tim Shoppa                        Email: shoppa(a)trailing-edge.com
 Trailing Edge Technology          WWW:   http://www.trailing-edge.com/
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