Ever ask yourself what you could do with a sixpack of beer, two servers, a bunch of data drives, and a collection of parts? 

Some of the following examples are based on a 9577 as a server. Note that the 85/95 series can use up to EIGHT SCSI adapters (NOT under W95 or Win 3.1x!). 

Still rooting for details on the software needed to run things in target mode. 

J. Clarke pointed out this High Availability Linux site 

Hacking NT4 Workstation for Fault Tolerance (file needed) 
   Registry Hack
Entry-Level Server
Server Using Disk Mirroring
Server Using Disk Duplexing
Server Using 3510 Enclosures
Server Using 3511 Enclosures
Backup Server using Two SCSI Adapters
Backup Server using One SCSI Adapter

Hacking NT 4 Workstation for Fault Tolerance
Original info from Systems Internals

   So you are bored. Significant other is gone for a while. No beer (or wine) in the fridge. Its dark, you're wearing sunglasses... 
   You have a pile of SCSI w/cache, an 85 or 95 class system, four SCSI drives (maybe more) and a desire to do something along the lines of RAID. Well, cheer up! I'm a gonna tell you how to become a RAIDer of the lost hack. 
   You need- a copy of NT 4 (original version is fine). Install and configure four SCSI controllers. Hang a drive seperately off each controller. Get the termination right! One drive will be for the system files (IML and/or program). Use three drives for data, program, or both. 
   You may also choose to run multiple drives off of one SCSI controller.This will work as well. Might even have performance benefits (only one drive controller is issuing commands, less overhead) look at the below illustrations and be imaginative. 
   Now you need a copy of FTEDIT.EXE from the NT Workstation Resource Kit. Place in Winnt\System32 or someplace on the path. Run FTedit. Choose Create FT Set. I'll have to diddle with the instructions some- this utility is crude. Add the other disks to the set. Save the change- write to the system. 

Registry Hack
   Use regedit32 (regedit is the one for 16 bit apps) Set HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\FtDisk\Start to 0. The next time you boot your workstation, the fault-tolerant drives you have created will be  functional. 
NOTE: Edit>DWORD and type 0 in the text box, leave Radix as Hex 
   Reboot. Don't use Disk Administrator, because the fault tolerant stuff will not be enabled. Run FTedit, and assign a drive letter to the stripe set. Close, and open "My Computer" (unmanly name. Insulting to the intelligence of both genders as well). Format the stripe set by choosing the drive letter you assigned. Stripe set should appear as a drive under Explorer. 

Entry-Level Server

 

This system has the programs, data and system files all on one disk. It cannot perform any special tasks like disk mirroring or duplexing. 
 
 
 
 
 

Server Using Disk Mirroring

 
 

All disks are attached to one SCSI controller, with the data being mirrored on the Primary and the Mirror drives. If the single controller fails, all data is inaccessible. 
 
 
 

Server Using Disk Duplexing

Disk duplexing is like Disk Mirroring, but each hard drive has it's own controller. This example shows an external drive being mirrored. Duplexing provides more fault tolerance than Mirroring because either drive or controller can fail and the data is still accessible. 
 
 
 

Server Using 3510 SCSI Enclosures

Advantages:
You can use disk mirroring. 

Fault tolerance can be increased by using disk duplexing. Duplexing allows you to access the data in the event of a disk or adapter failure 

You can turn off a storage enclosure and replace the hard drive without turning off the computer. 
 
 
 
 
 
 
 
 
 
 
 

Server Using 3511 SCSI Enclosures

Three of the four 3511 SCSI External Storage Enclosures contain seven SCSI hard drives. The fourth storage enclosure only has six SCSI hard drives because it's SCSI Adapter also supports the System Disk.. This example is for IML systems that require a System disk. A non-IML system could dispense with the system disk and use seven drives in each 3511. 

Backup Server using Two SCSI Adapters

In this example, one SCSI adapter in each computer is attached to the shared set of six 3510 SCSI Storage Enclosures. The other SCSI controller is attached to the system hard disk. 

NOTE the SCSI IDs for the shared disk set- the two SCSI controllers attached to the disk set have different SCSI IDs (ID 7 and ID 6). Also, the IDs for each SCSI device involved with this disk set range from 0 to 7. NO DUPLICATE IDs ARE ALLOWED!!! 

My question- Do you only terminate the adapters? Sure can't terminate any of the drives.. 

Backup Server Using One SCSI Adapter

 

In this example, both systems are attached to a set of SCSI disks in 3510 Enclosures. In both systems, the same SCSI adapter that is attached to the disk set also is attached to the system disk. NOTE that all devices connected to the disk set have SCSI IDs between 0 and 7. 

NO DUPLICATE IDs on SCSI devices attatched to the disk set allowed! amedico@calug.net  noticed a duplicate in the original diagram. He doesn't win anything, but he was right... 

   It seems that only the system disks have termination enabled. On IML systems, this setup REQUIRES the 44/45 SCSI BIOS and the enhanced complex BIOS (T1 and T2 need upgrade EPROM!). Note the SCSI adapter at ID6 and a system disk at ID4.