Re: Externally connecting internal IDE drives
From: Paul Carpenter (paul$_at_pcserv.demon.co.uk)
Date: 11/30/04
- Next message: starfire: "Re: Cold Heat Solder"
- Previous message: Bob McConnell: "Re: Multi-threaded Sockets Application"
- In reply to: Norm Dresner: "Re: Externally connecting internal IDE drives"
- Next in thread: Hans-Bernhard Broeker: "Re: Externally connecting internal IDE drives"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Date: Mon, 29 Nov 2004 23:47:56 +0000 (GMT)
On Monday, in article
<hIKqd.72319$7i4.49323@bgtnsc05-news.ops.worldnet.att.net>
ndrez@att.net "Norm Dresner" wrote:
>"Hans-Bernhard Broeker" <broeker@physik.rwth-aachen.de> wrote in message
>news:310mlvF34m1ngU2@uni-berlin.de...
>> In comp.arch.embedded Norm Dresner <ndrez@att.net> wrote:
>>
>> > SO .. Does anyone know of a reasonable way to "mount" IDE internal
>> > HDs & CDROMs externally?
>>
>> Please note there isn't really any such thing as an "internal"
>> IDE/ATAPI device --- they're all internal by definition. The only
>> question to decide upon is "internal to _what_?" The design assumes a
>> PC or something like it, but there are alternatives, most prominently
>> in the form of separate boxes that hold an ide drive and connect it to
>> something else.
>>
.......
>Alas, there are several problems with using any other attachment than IDE
>for the drives I want to use:
> 1. I have to be able to boot and run a variety of OS on each of the
>computers including standard MS-DOS which doesn't (natively) support USB,
>Firewire, or Ethernet. As a general rule, if I need to attach something
>external, it has to be IDE here.
Well it is possible to create a Boot ROM for network cards so it could boot
off a remote system via Ethernet and the ethernet can be supported under
DOS. Boot ROM could detect if the controller has a physical link to
establish if it should carry on or relinguish control back to the BIOS
to boot harddrive(s).
USB can be supported under SOME newer DOS variants (as used by Norton Ghost).
> 2. I have to be able to (re)install OS like Linux and Windows onto the
>actual removable drives that are housed in the drive carriers. Neither of
>these OS installation programs support USB or Firewire. Ethernet to another
>PC on the network is possible, though not necessarily easy nor reliable
Ethernet would be easier and cope with longer distances.
> 3. I'm not looking for hot-swappability, but simple reconfigurability
>from time to time for almost exclusively attaching a CD-ROM drive -- though
>on a very few occasions I've needed to attach a secondary HD so I could do a
>drive copy.
>
>I have, in each of the four rackmount chassis that I have, installed
>removable HD carriers and have several (boot) drives for each computer that
>simply slip in and out [with power off, of course]. This takes care of the
>basic HD's, but attaching a CD-ROM drive from time to time is then
>problematic. I suppose I could install a SCSI card in each box and use an
>external SCSI CDROM drive I have, but I don't always want to have SCSI part
>of the computer configuration because I'm trying to match the exact setup of
>various embedded systems for which I've developed and for which I write and
>maintain software.
That is extra support and back configuration that may be awkward.
>The removable HD sleds connect to their frames with just 50-pin Centronix
>connectors which carry both the normal 40-pin complement of IDE signals and
>the power and ground. I've tried using a commercial SCSI cable to allow one
WHY??
Why put a SCSI cable onto a connector configured to drive IDE/ATAPI?
You may have exceeded distances for drive, let alone the fact that the
interfaces could be wired differently so ground/power commoning could mess
up the signals. Also the power may have been going down insufficient
conductor size causing power drops.
>of the sleds to be external to the frame but the computer wouldn't boot with
>it installed and I'm pretty sure it's because the cable manufacturer is
>taking shortcuts and running fewer than 50 wires by using a common ground
>wire or two in place of the several in the normal SCSI configuration. I
I am pretty sure it is because you used lipstick as superglue.
>haven't been able to find any compatible cables made with ribbon cable where
>I could be guaranteed of 50 separate wires. If anyone knows of a source of
>50-wire ribbon cables with one each male and female 50-pin Centronix
>connectors, I'd be very grateful because I think that this would solve my
>problem.
At one site several years ago a class was setup for doing imaging training
and to ensure the students did not load any nastys, I made up for the
customer several cables to take the floppy interface from the motherboard
to a connector mounted on a blanking plate. Added to the cable several power
and ground conductors. Then made a box with a floppy drive and a SHORT cable
to a connector. This way at the time any boot/driver floppies could be
loaded by the administrator.
If the following conditions can be met
1/ CD-ROM is the ONLY device on the secondary IDE interface,
AND 2/ all your motherboards have Primary AND SECONDARY IDE interfaces,
AND 3/ At least one spare slot on ALL target systems
within SHORT distance from SECONDARY IDE interface connector
Then consider making a SHORT internal cable to blanking plate connector
of many pins, with MANY pins also assigned to take the power and ground.
Get a USB 5.25" USB CDROM empty case, and modify it to take a cable to
mate with the other connector as 1-1 connection all separate wires.
Make the cable SHORT to keep the distance of cable less than a normal
IDE cable length about 14inches or less.
CDROM will always be behind the unit, ensure the unit will be supported
and not hanging on the cable, or make a bracket to hold the CDROM box.
If necessary use 50pin Centronics connectors I am sure you could probably
buy pre-punched blanking plates that will take a 50pin Centronics connector.
You only need a couple for the box end (keep a spare or two), and at least
one of the opposite type for the computer ends
-- Paul Carpenter | paul@pcserviceselectronics.co.uk <http://www.pcserviceselectronics.co.uk/> PC Services <http://www.gnuh8.org.uk/> GNU H8 & mailing list info <http://www.badweb.org.uk/> For those web sites you hate
- Next message: starfire: "Re: Cold Heat Solder"
- Previous message: Bob McConnell: "Re: Multi-threaded Sockets Application"
- In reply to: Norm Dresner: "Re: Externally connecting internal IDE drives"
- Next in thread: Hans-Bernhard Broeker: "Re: Externally connecting internal IDE drives"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Relevant Pages
|
