CSPPC and Mixing UltraWide and Fast Scsi Devices

[reflex]

Hello,

I have a quite expanded Amiga 4000 with a PPC and a lot of drives.

Here there is my chain:

- Termination
- Controller
- Quantum Atlas 9GB HD
- Fujitsu 76GB HD
- Acard 7730A with 120GB Sata SSD
- 68=> 50 pin adapter wit upper bites termination
- Iomega ZIP 100
- Iomega JAZ 2GB
- Sony 40X CD-ROM
- Yamaha 4x4x16 CD-Burner

The hard drive will be unmounted as soon as I copy everything on the SATA hard drive, i bought it as the other hard drives are way too noisy.

Anyway I read somewhere that mixing UW devices with SCSI-2 ones will slow down the whole chain to 10 mb/s speed, but this doesn't happen with UltraScsi ones.

But How can i understand what of my devices are SCSI-2, Fast Scsi or Ultra SCSI?

I guess that the iomega Jaz is an Ultra Scsi device but what about all the other ones?

Moreover will a Fast SCSI device slow down the whole chain too?

Any suggestion/advice is welcome.

[grelbfarlk]

I have a CSPPC with an UW 320 HDD, UW SCSI to IDE, U20 CF adapter, SCSI-II CDROM and it still does 30MB/s, so I don't know.

Jaz is SCSI-II Fast
Zip is SCSI-II
As far as the rest you'll have to look them up.

All I can suggest is benchmark your fastest drives.

Yes that is what they say, but I've never actually seen it work that way. On my WarpEngine I have a SCSI-1 CF reader with a SATA SSD and the SSD still performs near the max of the Warpengine SCSI-II Fast limit, ~9MB/s. Other systems are similarly mixing Ultra, SCSI-II Fast and SCSI-1 drives with no apparent slowdown to the lowest speed.

[reflex]

what is the best software to check system speed?
I use scsibench but it gives me extremely low values, something like 4mb/s that seems to me to be way too low.

Moreover did you switched all the drives to synchronous mode?

[Locutus]

Configuring SCSI chains....not a fond memory...

But for mixed 8/16bit mode SCSI your setup is correct.

Recommended is:

Active 16 bit terminator -> Controller -> <16bit devices> -> Terminate upper 8 bits -> <8 bit devices> -> terminate lower 8 bits.

[grelbfarlk]

Originally Posted by reflex

what is the best software to check system speed?
I use scsibench but it gives me extremely low values, something like 4mb/s that seems to me to be way too low.

Moreover did you switched all the drives to synchronous mode?

Yes, you say you have PPC, I guess you mean CSPPC? You need to run unitcontrol .... or whatever that Phase5 utility is to actually set faster modes, or configure it in the CSPPC BIOS. Yes I have Synchronous set-always. Sysspeed is pretty good, or RSCP.

[reflex]

Originally Posted by grelbfarlk

Yes, you say you have PPC, I guess you mean CSPPC? You need to run unitcontrol .... or whatever that Phase5 utility is to actually set faster modes, or configure it in the CSPPC BIOS. Yes I have Synchronous set-always. Sysspeed is pretty good, or RSCP.

I already used Unit control, but it tells me that all the devices are Scsi-2 even if I make a chain with UltraWide only devices plugged.

Anyway i'd like to get some suggestions about benchmarks, what is the best program to test the speed of the devices?

I used SpeedMonTools and ScsiBench but i have some doubts about the results they give.