N
Norm Dresner
Guest
Here's my original posting
============ OP =============
I have a very large and complex rack-mounted box which contains a 14-slot
ISA bus passive backplane [physically divided into 2 separate PC segments]
and 12 cards of various sorts installed. The box has physical room for
mounting 3 drives in the front opening in which I have a floppy and 2
removable HD frames for one of the PC's and I have internally mounted a
permanent HD and made a cutout in the back panel for a floppy for the second
PC in the box. Everything works well ... Until I need to attach a CDROM
drive to one of the PC's. Currently I've got the cables from the secondary
IDE controllers and a power cable hanging outside the box and I simply hang
a CDROM drive (or a temporarily needed HD) from the cables. That's ugly
and, even though it's a very low traffic area, still quite unstable and
probably unsafe as well.
=================
Some people have helpfully suggested using an attachment method other than
IDE to accomplish what I want to do. Alas, there are several problems with
using any other attachment than IDE for the drives I want to use.
Here's additional background:
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.
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
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.
4. Finally, regardless of the availability of alternate technologies,
assume that for a variety of reasons I _must_ connect IDE devices which are
normally mounted internally in an external manner. If for no other reason,
it's the only way that seems to work consistently across the range of OS &
uses I have.
In each of the four rackmount chassis that I have, I've installed removable
HD carriers for the regular drives 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 problematic. 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. Also, MS-DOS doesn't (easily) support SCSI without
additional drivers which can wreck the memory configuration I'm trying to
preserve.
One solution I've tried is the following:
The removable HD sleds I use connect to the frames with 50-pin Centronix
connectors which carry both the normal 40-pin complement of IDE signals and
the power and ground. In an attempt to extend this outside of the box so I
could use an internally mounted drive sled frame with an external sled,
I've tried using a commercial SCSI cable to connect a sled outside 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 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.
Norm
============ OP =============
I have a very large and complex rack-mounted box which contains a 14-slot
ISA bus passive backplane [physically divided into 2 separate PC segments]
and 12 cards of various sorts installed. The box has physical room for
mounting 3 drives in the front opening in which I have a floppy and 2
removable HD frames for one of the PC's and I have internally mounted a
permanent HD and made a cutout in the back panel for a floppy for the second
PC in the box. Everything works well ... Until I need to attach a CDROM
drive to one of the PC's. Currently I've got the cables from the secondary
IDE controllers and a power cable hanging outside the box and I simply hang
a CDROM drive (or a temporarily needed HD) from the cables. That's ugly
and, even though it's a very low traffic area, still quite unstable and
probably unsafe as well.
=================
Some people have helpfully suggested using an attachment method other than
IDE to accomplish what I want to do. Alas, there are several problems with
using any other attachment than IDE for the drives I want to use.
Here's additional background:
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.
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
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.
4. Finally, regardless of the availability of alternate technologies,
assume that for a variety of reasons I _must_ connect IDE devices which are
normally mounted internally in an external manner. If for no other reason,
it's the only way that seems to work consistently across the range of OS &
uses I have.
In each of the four rackmount chassis that I have, I've installed removable
HD carriers for the regular drives 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 problematic. 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. Also, MS-DOS doesn't (easily) support SCSI without
additional drivers which can wreck the memory configuration I'm trying to
preserve.
One solution I've tried is the following:
The removable HD sleds I use connect to the frames with 50-pin Centronix
connectors which carry both the normal 40-pin complement of IDE signals and
the power and ground. In an attempt to extend this outside of the box so I
could use an internally mounted drive sled frame with an external sled,
I've tried using a commercial SCSI cable to connect a sled outside 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 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.
Norm
