A2091 and external Zip Drive

[k4lmp]

I asked about this on another thread, but didn't want to hijack the thread, so I started a new one.  We were discussing the external scsi connector on an A2091, and whether or not the on board terminators had to be removed to use the external db25 connector.  Also, if the internal 50 pin and external db25 could both be used together.  I have an external scsi zip drive I'd like to play around with on my A2000 with an A2091.  Has anyone ever done this, and if so, how well does it work?  I have several old zip disks laying around, and 100m would be a lot of storage for an Amiga.  I am wondering, if it would even work, if you could partition, and format the zip disk to be recognized as a HDD.

[Matt_H]

Yes, you should be able to use the internal and external connections simultaneously. I don't recall any termination challenges with the 2091, just make sure the Zip drive is terminated.

You should be able to install an RDB to a Zip disk and use it like any other hard drive. I say "should" because Zip disks have some extra hardware features that are software controlled, hence the program IOTools included in OS3.9 (and 3.5?). Not sure if there might be issues if you don't have that program available. Worth trying, though.

It was SyQuest drives that were popular amongst Amigans back in the day, which I know with certainty could be partitioned and formatted without issues (apart from the high defect rate of the cartridges).

[danbeaver]

I've done it with Jaz drives, both internal and external; just terminate each end of the bus. For the cost of storage, SCSI hard drives coming out of service (from servers) are 10 fold cheaper than Zip & Jaz drives

[mechy]

I asked about this on another thread, but didn't want to hijack the thread, so I started a new one.  We were discussing the external scsi connector on an A2091, and whether or not the on board terminators had to be removed to use the external db25 connector.  Also, if the internal 50 pin and external db25 could both be used together.  I have an external scsi zip drive I'd like to play around with on my A2000 with an A2091.  Has anyone ever done this, and if so, how well does it work?  I have several old zip disks laying around, and 100m would be a lot of storage for an Amiga.  I am wondering, if it would even work, if you could partition, and format the zip disk to be recognized as a HDD.

If you have no internal devices on the scsi chain and just plan to use the zip,then the controller should be terminated and the zip terminated. i.e. the controller is one end of the bus,and the zip the other end.
2091(terminated)----->external zip drive(terminated)


If you have BOTH internal and external devices, the terminators should be removed off the 2091 and the zip and internal drive should be terminated .In this case the internal scsi drive is one end of the bus and the zip is the other end,the controller is in the middle hence why its not terminated in this case.


internal hd(terminated)--->2091(unterminated)<----external zip(terminated)

Scsi is pretty simple,just remember the 2 ends of the chain always need to be terminated and middle drives do not. The 2091 is device #7 and sometimes its a middle device(when you have internal and external devices) and sometimes its one end of the chain(internal drive only or external only) depending on your config. Remember no middle chain devices should ever be terminated.
I hope that makes sense.

Mech

[k4lmp]

OK, so if I understand correctly, I am using my scsi card reader as an internal HD, along with a CDRW, which is terminated.  In order to use the external zip drive, I would have to remove the terminators on the A2091 board, and terminate the zip drive.  Since my internal drive is already terminated, it is OK.  I think that is how I understand it.

[Ral-Clan]

Also, try and get revision 7.0 ROMs for the A2091.  It might have problems with removable media devices otherwise.

[k4lmp]

Yeah, I had 6.6 roms, but replaced with the 7.0 already.  I also replaced the scsi controller chip to the latest revision, I got that chip from mechy.

[Azryl]

I have successfully used pcmcia scsi connectors and external zip drives

http://aminet.net/package/disk/misc/hdinst

which seemed to work reliably for removable media. You might need IDEfix software to allow the removable media to re-mount after a disk swap.

you might also need to use this util

http://aminet.net/package/disk/misc/ExistsSCSIDEV

and modify your startup-sequence to check if a valid disk is in your zip drive,
a simple if exists then mount else do nothing etc

Az